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1. 3 William Lonc Radio Astronomy Projects Third Edition 2006 Radio Sky Publishing page 32 4 Ibid pages 25 26 5 Ibid page 33 6 Chris Brown Computer Simulation of a Meridian Transit Radio Interferometer SARA Journal 1997 11 12 pdf pp 11 15 7 G W Swenson Jr An Amateur Radio Telescope Sky and Telescope May through October issues 1978 He has two other interesting articles 1 Antennas for Amateur Radio Interferometers Sky and Telescope April 1979 and 2 An R F Converter for Amateur Radio Astronomy Sky and Telescope November 1979 I got copies of those articles at a local university library 8 408 MHz Interferometer at 2013 SARA Conference October 2013 SARA Journal pages 70 73 Kenneth Kornstett holds a Masters of Physics degree from the University of Tennessee He has worked in various technical and engineering jobs for various companies in the US and overseas He once taught several three day microprocessor seminars in major cities across the US in the 70s He can be contacted via email at kennethk us yahoo com Please put cheap and simple interferometer in the subject line 35 STOW THIS CRATE OF FUNDAMENTAL FORCES IN THE HOLD FASTEN THE LIFEBOATS SECURE THE DECK AND HOIST THE SAILS A Higgs Bosun Cartoon by Nick D Kim Strange Matter net Used with permission 36 Phase Stability Loss Stability and Shielding Effectiveness Paul Pino Reprinted
2. RADIO AS TRONOMY Journal of the Society of Amateur Radio Astronomers September October 2014 radio asTronony org Ken Redcap SARA President Kathryn Hagen Editor Whitham D Reeve Contributing Editor Christian Monstein Contributing Editor Stan Nelson Contributing Editor Lee Scheppmann Technical Editor Radio Astronomy is published bimonthly as the official journal of the Society of Amateur Radio Astronomers Duplication of uncopyrighted material for educational purposes is permitted but credit shall be given to SARA and to the specific author Copyrighted materials may not be copied without written permission from the copyright owner Radio Astronomy is available for download only by SARA members from the SARA web site and may not be posted anywhere else It is the mission of the Society of Amateur Radio Astronomers SARA to Facilitate the flow of information pertinent to the field of Radio As tronomy among our members Promote members to mentor newcomers to our hobby and share the excitement of radio astronomy with other interested persons and organizations Promote individual and multi station observing programs Encourage programs that enhance the technical abilities of our members to monitor cosmic radio signals as well as to share and analyze such signals Encourage educational programs within SARA and educational outreach initiatives Founded in 1981 the Society of Amateur Radio Astronomers I
3. software education research strategies philosophy and observing efforts and methods are welcome Formal proceedings will be published for this conference If presenters want to submit a paper or a copy of their presentation we will make them available to attendees on CD Basic schedule Our first day will include a visit to the KIPAC facilities at Stanford Linear Accelerator Center SLAC The next two days meetings will take place on the Stanford University campus and will include presentations by members and guest speakers Getting there Fly into San Jose or San Francisco airports and rent a car to drive to Palo Alto Registration Registration for the 2015 Western Regional Conference is just USS55 00 This includes breakfast and lunch on Saturday and Sunday Payment can be made through PayPal www paypal com by sending payment to treasurer radio astronomy org Please include in comments that the payment is for the 2015 Western Regional Conference You also can mail a check payable to SARA 2189 Redwood Ave Washington IA 52353 USA Please include an e mail address so a confirmation can be sent to you when we receive your payment Hotel reservations TBA What to wear Our conference settings are casual Saturday night dinner We will make a group dinner reservation at a local restaurant for Saturday night Additional Information Additional details will be published online at www radio astronomy org meetings and in the SARA journal R
4. superstorm just missed Earth in 2012 or time to build your underground shelter and stock up on canned chili and AA batteries http www cbsnews com news solar super storm just missed earth in 2012 Original newsreel story dedication of the Jim Creek VLF transmitter NLK in 1953 U S Navy opens 1 megawatt transmitter in Cascade Mountains of Washington known as Radio Jim Creek https archive org details LargestR1950 See also http www navy radio com commsta jimcreek htm Spectrum Management for Radio Astronomy Proceedings of the IUCAF Summer School Green Bank 2002 http www iucaf org sschool procs 74 Radio quiet please protecting radio astronomy from interference http arxiv org abs 0906 2268v1 Sky amp Telescope magazine October 2014 issue Discovering the Radio Sun The wartime discovery of radio emissions from the Sun gave birth to the field of solar radio astronomy http www skyandtelescope com sky and telescope magazine inside october 2014 issue Primers from Marki Microwave Balun Basics http www markimicrowave com Assets appnotes balun_ basics primer pdf Mixer Basics http www markimicrowave com Assets appnotes mixer_ basics primer pdf Power Dividers and Couplers http www markimicrowave com Assets appnotes microwave_power_dividers_and_couplers_primer p df Radio News Radio amp Television News Radio amp TV News magazines from 1919 through 1959 Electronics World magazine from
5. 15 found that he needed to use bandpass filters in front of them But in general they work quite well especially considering that they cover the huge range of frequencies from 950 to 2150 MHz Figure 6 12 Now it was time to say goodbye to software timed sampling and the parallel port for several reasons Software loops can only run uninterrupted on simple operating systems like DOS A software loop cannot be synchronized to an external clock as needed for VLBI The parallel port is too slow only sampling rates below a MHz or so are possible There is no parallel port on modern computers After pondering about several interfacing options like FireWire and PCI I decided to use USB because it is widely available has an adequate bandwidth and it looks I hope like it won t be obsolete very soon In its 2 0 version is has a theoretical maximum raw throughput of 480 Mbit s In practice with moderate sized FIFOs first in first out high speed data buffers on the device side about 100 to 200 Mbit s can be pumped through it continuously without losing data due to OS latencies In 2007 made an USB interface 17 and a simple sampler 18 that could sample at up to 40 MHz on four channels two interferometer channels with I O each upgraded and ported the software to Linux gcc and did the first table top tests with SIDI v1 2 But then got married and Pavle started a start up so SIDI v 1 2 got sidelined for some years
6. Figure 4 Left The 4 in sewer line is laid in a trench from the new building location The vertical pipe in the middle of the picture is a cleanout near the new building The tower foundation is seen at upper right Right The septic tank is almost completely buried in this picture The two vertical black pipes are vents and inspection ports Part of the turquoise line to the drain field and a monitor tube can be seen in the background Images 2014 W Reeve 4 Foundation looked at two alternative foundation types one using buried Sonotube concrete forms and another using a driven metal helix post system By now was tired of mixing concrete so contracted with Techno Metal Post Alaska to install helix posts A special diesel powered wheeled vehicle is used to hydraulically screw the posts into the ground figure 5 Each post is driven until a predetermined torque limit is reached The torque is related to the load rating of the post as determined from engineer certified load charts and tables The post layout is simple figure 6 The helix posts are 3 5 in diameter x 8 ft long If a longer length is needed to achieve the desired driving torque a 7 ft pipe section is welded to the first with a coupling for alignment and driving continues This process is repeated as necessary until the needed torque is reached Any excess lengths are simply sawed off In my installation because of the extremely hard ground underneath the top soils on
7. o Filter out DC offset and image freguencies Average together several files o Slow down the fringes o Apply additional time averaging o Show the FFT spectrum of the fringes o Show a spectrogram over the whole duration of a file o Show fringe amplitude and phase 13 5 Some results of the first observations with SIDI v1 2 e Pavle has put many of the daily recordings onhis webpage 20 where they can be downloaded e Fig 7 shows a section from one of the first recorded files with only pulse blanking and DC image filtering applied The fringes are from a group of unresolved sources at 1720 0058 with a total flux of about 55Jy1720 0058 with a total flux of about 55 Jy e Fig 8 shows the same data after a slowdown of 13 mHz The slowdown is a simple freguency conversion done by multiplication with a complex sinusoid Now additional averaging over 127 points can be applied with the results shown in fig 9 Figure 8 Figure 9 14 On the second of April an interesting side catch appeared in the recording At first thought it was just terrestrial QRM manmade radio interference but later next day when saw people discussing a solar burst on the SARA mailing list checked the timing and it was dead on Time goes vertically from top to bottom and fringe frequency is on the horizontal axis The bright crescent is the quiet Sun coming in through the sidelobes a few degrees off the main beam The crescent shape comes
8. only one circle may appear as shown here otherwise two appear The two circles at bottom middle are archive movies from the previous several days The movies cover a full day often with gaps and each reguires about 12 minutes to run Sometimes radio freguency interference is seen along the edges of the circles The aerial image of the LWA at lower left is fixed and text on right changes depending on normal or beam pointing view of the live image Image source http fornax phys unm edu lwa trac wiki EPO 5 Installation and Operation Notes This section provides information that will help first time users It is focused on the LWA TV application Software installation The brief instructions here assume the reader is using a Windows PC to install the LWA TV GUI software on the memory card 1 Install 7 Zip 7 Zip SD Formatter SDFmt and Win32 Disk Imager WDlmg on the Windows PC When running the latter two programs run them as Administrator 2 Put the memory card in a card reader see Note below connected to the PC and use SD Formatter to format the card In SD Formatter set the Options to Format Type Full Erase and Format Size Adjustment On 3 Download the LWA TV GUI software image for the RPi from LWASoft The file is compressed so decompress it with 7 Zip to a raw image file img This will take a few minutes 4 Write the software image to the memory card with Win32 Disk Imager using its default settings This will take a few
9. 1959 through 1972 and more http www americanradiohistory com Radio News Master_Page_Guide htm dB or Not dB Everything You Ever Wanted to Know About Decibels But Were Afraid to Ask http techonline com electrical engineers education training tech papers 4127502 dB or not dB Everything You Ever Wanted to Know About Decibels But Were Afraid to Ask RF Electronics Engineering Blog let us know what you think of this https jaunty electronics com blog 75 Online Resources British Astronomical Association Radio Astronomy Group http www britastro org baa CALLISTO Receiver amp e CALLISTO http www reeve com Solar e CALLISTO e callisto htm CALLISTO data archive http e callisto org Deep Space Exploration Society http dses org index shtml European Radio Astronomy Club http www eracnet org GNU Radio http www gnu org licenses gpl html Inspire Project http theinspireproject org NASA Radio JOVE Project http radiojove gsfc nasa gov Archive http radiojove org archive html National Radio Astronomy Observatory http www nrao edu NRAO Essential Radio Astronomy Course http www cv nrao edu course astr534 ERA shtml Pisgah Astronomical Research Institute http www pari edu SARA Web Site http radio astronomy org SARA Email Forum and Discussion Group http groups google com group sara list Understanding Engineers H4 Radio Astronomy Supplies http www radioastronomysupplies com Radio Sky
10. 4 Current state of SIDI development e n January 2014 dusted off SIDI v1 2 fig 6 and restarted work on it Pavle has some nice 3m dishes so made a couple of simple cantenna feeds from 4kg cans of peppers and pickles acquired in the cafeteria at my work e n March I visited Pavle and we set up a baseline of around 42m E W with two 3m dishes One of them was just laid on sloping ground and fixed with some sticks and ropes 19 It determined the fixed declination of about 0 5 degrees at which the setup then ran in drift scan mode for about a month e The signals were fed into the house via two equally long cables made of low loss satellite TV coax the one with foil shielding and foam dielectric The cables had about 15dB of loss and the NAs had gt 35dB of gain leaving about 20dB to cover the tuner noise This is somewhat marginal considering that the tuner s 3000K still contributed 30K to the system noise about the same as the LNAs and the antenna noise estimated the total system noise to be around 100K e Sampling ran at 20MHz and the observation software averaged 16M 2 samples in real time for each correlation value recorded into the file This gave a recorded data rate of 1 2Hz creating a 3 5MB file in 24 hours e The recorded files can be later reviewed with a special viewing and filtering program called isci_ fringe means search for fringes in Slovene which can o Remove impulsive noise pulse blanker
11. 49 me Pull Configuraton Eamc options for your Fu I TY session d oo Specify the dewination pou went bo connect bo _ END Fest Mame ur F edcress Poil r Rey Eel 100021 22 Fab me Connection byeu E Wr Rew C Tena Alegn SSH C Seia gych Load save or delete a anrec sason Translation sawed Sasaona Selector Colour 45 i E Connector ee Se _ boed Data Save r gt Proxy Tel Dalea r Regi FF 55H Serial ose window on gt Aways C Never L om Cmen IF Dry on dean ad of pifhvatugui Lagin aa Ed Linux lwatwmui 2 127 26 707 PREEMPT Sat Aug 3D 17 29 13 BST 2 The programs included with the Debian GU Linux system are frm che sxacr diatriboucian terms for each progran are described in individual files in fuer share desc copyright eblan GEUZ LEUR comes with ABSDLLIELY MO WARRANTY to the permitted by applicable law Last Login Hon Sen 3 10 35 22 piBlwaregul f RETI 2014 from 10 0 0 TE PuTTY Security Alert E x The server s host key is not cached in the registry You A hare no guarantee that the server is the computer you thins rt i The server s rsa key fingerprint is saree MHE 09245 52501 37 ba c ad 2b 24 beicd 4c an gr 6 If you trust this host hit Yes te add the key to PUTT Y s cache and carry on connecting Ef you want to carry an connecting just once without adding the key to the cache hit Mo If you do nat trust this host hit Cancel
12. CENTS per foot odd lengths from 13 to 19 All are plus shipping Will consider offers Items are surplus and all proceeds go to support the SARA Stanford SuperSID project Contact Bill Lord 319 591 1131 or email supersid radio astronomy org 77
13. Events data see Figure 5 In Figures 2 and 5 the cosmic ray light curve has distinct dips which appear to match to the solar maximum times and cosmic ray maximum peaks which appear to match to the solar minimum times cosmic_ray smoothing splines _fay cosmic ra 45 50 55 60 65 70 75 440000 444000 448000 452000 jdt Figure 5 might also show that there are other phenomena than active region group counts or solar flares recorded as SID Events which are being modulated by the sun 1998 H Mavromichalaki et al and see Neutron Monitor Database http www nmdb eu sites default files NMDB Brochure 1 pdf So what do the statistics show The first step is to take the first difference of the group counts data and the first difference Climax Neutron Monitor data And also take the difference of the SID Events data These first differences one data element subtracted from the next data element in the time series http people duke edu rnau 411diff htm can then be compared to a normal distribution From this we can draw regression lines and do a pairwise comparison to look at positive or negative slopes 24 Welch Two Sample t test data VLF and CR t 0 0059 df 6361 541 p value 0 9953 95 percent confidence interval Da ODD 074984591 sample estimates mean of x mean of y OS00USTT56LL O 200119 S50 59 it i i TE TE TE TE TE TE TR TE EE EE TR TE HE TR TR TR EE EEE EE data group and CR t 0
14. Melinda Lord at treasurer radio astronomy org There is no charge to place an ad in Radio Astronomy but you must be a current SARA member Ads must be pertinent to radio astronomy and are subject to the editor s approval and alteration for brevity Please send your For Sale Trade or Wanted ads to editor radio astronomy org Please include email and or telephone contact information Please keep your ad text to a reasonable length Ads run for one bimonthly issue unless you request otherwise For sale RFSpace SDR 14 S N KI001026 new in box asking 975 Price negotiable includes postage Contact Dave Typinski davetyp typnet net For sale Items listed below Send request to SARA by email to supersid radio astronomy org For more information http www radio astronomy org pdf sid brochure pdf Description items for sale by SARA Price USS SuperSID VLF receiver assembled 48 00 PCI soundcard 96 kHz sample rate 40 00 Antenna wire 24 AWG 120 m 23 00 Coaxial cable Belden RG58U 9 m 14 00 Shipping United States 10 00 Shipping Canada Mexico 25 00 Shipping all other 40 00 For sale Description items for sale by SARA Price USS New in box twist on male TNC Connector for RG 58 cable 23 available S1 00 each New Berk Tek twist on male TNC Connector for RG 59 cable 10 available S1 00 each New twist on male BNC connector 1 Piece 50 ohm for RG 6 cable 21 available 1 00 each Belden RG58U Coax 25
15. Observatory NRAO in Green Bank WV The following excerpt is from WVU website I m an astronomer interested in compact objects black holes neutron stars and white dwarfs which I study using radio pulsars rapidly spinning highly magnetized neutron stars Pulsars are great fun to study and have lead to a lot of exciting adventures over the years A nice behind aie scenes ade describing how this work is carried out can be found here I arrived at WVU in May 2006 from the Jodrell Bank Pulsar Group where I worked as a Royal Society Research Fellow Before that was at Arecibo Observatory 1998 2001 and at the MPIfR in Bonn 1995 1998 My research revolves around surveys for radio pulsars and what they tell us about the population of neutron stars This work is carried out with many collaborators and uses some of the classic radio telescopes around the world Of particular interest are young energetic pulsars and binary systems where the orbiting companion is a white dwarf a main sequence star another neutron star and perhaps soon a stellar mass black hole February 13 15 2015 Hamcation Orlando Florida http www hamcation com March 20 22 2015 SARA Western Conference at Stanford University Palo Alto California http www radio astronomy org node 177 May 15 17 2015 Hamvention Dayton Ohio http www hamvention org index ph June 21 24 2015 SARA Annual Conference at National Radio Astronomy Observatory in Green Bank
16. Publishing http www radiosky com RF Associates Richard Flagg rf hawaii rr com 1721 1 Young Street Honolulu HI 96826 RFSpace Inc http www rfspace com Shirleys Bay Radio Astronomy Consortium marcus propulsionpolymers com Simple Aurora Monitor Magnetometer http www reeve com SAMDescription htm SETI League http www setileague org SkyScan Science Awareness Meteor Detection http www skyscan ca getting_started htm Stanford Solar Center http solar center stanford edu SID UK Radio Astronomy Association http www ukraa com www SARA Facebook page https www facebook com pages Society of Amateur Radio Astronomers 128085007262843 SARA Twitter feed https twitter com RadioAstronomy1 What is the difference between mechanical engineers and civil engineers Mechanical engineers build weapons Civil engineers build targets 76 For Sale Trade and Wanted Sara Polo Shirts SARA has polo shirts with the new SARA logo embroidered No pocket These are 50 cotton and 50 polyester machine washable Currently in Size Color Small Navy Royal Blue Medium Navy Dark Green Royal Blue Large Maroon Black Navy Royal Blue X Large Maroon Black Navy Royal Blue XX Large Maroon Black Navy Dark Green Royal Blue XXX Large Black Navy Dark Green Royal Blue stock Price is 15 with free shipping in the USA Additional cost for shipping outside the USA Other colors and sizes available contact SARA Treasurer
17. Radio Telescope where he listed mistakes to avoid 2 My main objective was to detect fringes at a minimum cost cheap but did not expect to encounter dumb mistakes in the process The topic will be examined in four steps system description fringe data analysis declination calculation and final comments During the paper decisions assumptions and mistakes are listed 2 Brief system description To detect fringes one uses an interferometer system The simplest radio interferometer sums the output of two antennas to get interference fringes knew that needed two antennas minimum to get fringes and had read somewhere the spacing between the antennas interferometer baseline should be at least 8 wavelengths William Lonc in his book gives an interferometer spacing rule of thumb the more the better 3 However he warned that for an extended source like the sun some baselines can cause the visibility function to be zero which would prevent observing fringes 4 The block diagram of the cheap and simple interferometer described and used in this paper is shown in Figure 1 ra LNBF cr Y y amp yr amp o signal summer satellite finder digitizer laptop A power inserter Figure 1 Cheap and Simple Interferometer Block Diagram 28 Notice on the block diagram there are two antennas which are summed then the resultant signal is detected with a satellite finder The digiti
18. Raspberry Pi The Raspberry Pi abbreviated RPi throughout this article is a small computer platform designed for educational purposes by the Raspberry Pi Foundation RPi The RPi is low cost about 35 USD 40 USD with memory card and has HDMI video Ethernet LAN and USB interfaces figure 3 It is euphemistically advertised as credit card size but actually is much larger It can be plugged into an ordinary computer monitor or TV and can use a Wi Fi wireless access device for LAN and internet access and wireless or wired USB keyboard and mouse i F263 TG howls sie EF oes Figure 3 Raspberry Pi model B and B hardware The model B is shown in the middle with an optional clear plastic enclosure The model B on the left is in an optional milled aluminum enclosure and is shown with a Bluetooth USB dongle The model B on the right is in a molded clear plastic enclosure and rotated to show the opposite end The interfaces vary slightly between the model B and B Enclosure dimensions are approximately 100 x 65 x 25 mm Image 2014 W Reeve The RPi hardware usually runs an operating system derived from Linux and as of this writing has become available in three versions original model A model not generally available in North America model B and model B The model B and B are compared table 1 For the LWA TV application there is no advantage of one over the other model have not tried the RPi model A and initial
19. a hot source like a semiconductor noise source hot part of the Milky Way galaxy the sun or any other hot broadband radio source to obtain lhot The smallest change in noise temperature amp T that we can observeis eguivalent to the standard deviation or root mean square rms value of the noise source noise ace which we can calculate from the statistics of the pot data The last part of equation 3 follows from equation 2 The advantage of this approach is we do not need to know the actual noise temperature or received flux because SNR is dimensionless In my case for the Callisto receiver the radiometric bandwidth is in the order of 300 KHz and the integration time is 1 ms Therefore the SNR should be about Y 5DU 17 3 This will be compared to actual measurements shown in figures 1 through 4 5 Sun observation off on off made raw data 1 Figure 1 A typical light curve of a telescope movement through the position of the sun witha 5 m parabolic dish at 1152 MHz The intensity is un calibrated and expressed in digits read from Callisto s analog digital converter ADC Intensity ADC units o vr o o rT o 0 100 200 300 _ 400 500 600 700 800 Time s 19 a Sun observation aff on aff mode detector voltage 1 1750 1700 Figure 2 The same data as in figure 1 but now 2 1650 expressed in mV as measured by the ADC where 4600 the ADC s full scale range is 2500 mV i 1550 1500 I _ digits
20. chamber 38 wn The following test procedure was employed as seen in Diagram 2 Fr lt left The cable assembly was coiled with loops approximately 1 termination foot in diameter The coiled assembly was placed atop a non SITE conductive pedestal in the middle of the mode stirred chamber In this configuration two sets of test data were collected One data set was collected while the cable assembly connectors were wrapped in a fine grade steel wool another set collected while the cable assembly connectors were left unwrapped Steel wool serves as a supplementary shielding material when wrapped YND DU around the cable assembly connectors this technigue is used Non conductive pedestal shown purely for test purposes By comparing the shielding effectiveness performance of an assembly with connectors wrapped versus unwrapped one may more easily determine if the major contributor to RF leakage is connector or cable Cable assembly connector Test lead As a final test the cable assembly was hung in loose loops over a nonconductive line strung within the mode stirred chamber Test conditions were as stated above Data was collected for tests with and without connectors wrapped in steel wool 5i clurm Cable termination ass r s connector ext bead Looped Test Configuration Non conductive Line and pedestal shown ps CONCLUSION Phase Stability and Repeatability Figure 1 illustrates the phase stability
21. good display With many settings had no display at all soent about one full day trying different port settings on the monitor and RPi finally gave up and settled on using only the monitor s HDMI port This monitor works very well at 1440x900 pixel resolution with the VGA interface on the lab PC also tried our Philips 47 in LCD television set This TV has three HDMI ports and supports several resolutions 480p 720p 1080p and 1080i I found I could obtain a nice picture using RPi settings for 720p hdmi_group 1 hdmi_mode 4 and overscan overscan_right 40 overscan_left 40 overscan_top 16 overscan_bottom 16 figure 11 Although this TV supports 1080p and 1080i I could not find any RPi overscan settings that provided a properly positioned horizontal display Based on my experience so far think the video interface implementation is the RPi s biggest shortcoming the video implementation is separate from the LWA TV GUI Perhaps with enough time and experimentation could make it work better at different resolutions 51 Mews for Seer 8 Bol ws ic A la a i e W i ost uo Figure 11 Philips 47 in LCD television set connected through one of its HDMI ports to the RPi The RPi HDMI port was set for 720p resolution see text Image 2014 W Reeve As a final video test connected a Dynex 19 in LED LCD TV that I use in the lab This is a small set designed as a kitchen counter TV with a wide range of video inp
22. illustrates the phase repeatability of the cable assembly Providing a practical example will highlight the importance of repeatability The 50 foot test assembly is uncoiled and connected to its respective instrumentation The necessary calibration procedures are followed and phase is noted at 10 GHz after which the assembly is disconnected coiled and stored for future use A short time later the cable assembly is uncoiled and reconnected to this same instrumentation and phase is noted Referring to Figure 2 the user can expect to observe a change in phase of approximately 0 400 degrees at 10 GHz 20 degrees Celsius ambient temperature Loss Stability and Repeatability Figure 3 depicts the loss stability of the test assembly when going from a coiled to an uncoiled state At 10 GHz a 0 080 dB change is indicated which correlates to 0 54 of the test assembly s insertion loss at this frequency At 2 GHz a 0 015 dB changes is indicated correlating to 0 24 of the test assembly s insertion loss at this frequency Change ln ios from Initia coiled state dB H 060 n 050 1 040 URIET U uzu UU LU 0 000 gaii 0 020 I nan Haai Insertion Loss Repeatability 50 ft Assembly Return to Coiled State TM MH HN LA oo o o 7 WN TWN WYW NA we 2 4 G 10 Frequency GHz GHz 20 degrees Celsius ambient temperature 40 12 Aei tr Twrw 16 Th Figure 4 illustrate
23. j Pi 1 SW Figure 2 Image from LWA TV as seen on the internet The two circles represent the sky seen by the LWA at radio freguencies in this case 37 80 MHz The horizon is along the circle edges and the zenith straight up is in the middle of each image Dark blue is the background and brighter areas in order of increasing radio intensity blue green yellow red are the Milky Way galaxy and spots are radio sources The locations of some of the brighter celestial radio sources are labeled The images show total intensity left and intensity of circularly polarized radio waves right Image source http www phys unm edu lwa lwatv html Although LWA TV can be watched in near real time on any PC with internet access observers may want to setup a dedicated monitor for LWA TV and then use the PC with their own radio telescope For example one could observe Jupiter or the Sun with their own radio telescope using Radio SkyPipe RSP or Radio Sky Spectrograph RSS while watching for activity on LWA TV This allows confirmation or correlation of observations Of course the radio sources would need to be in common view of the LWA and the observer s radio telescope Another application is radio astronomy club outreach The setup could be used at meetings conventions and 43 conferences It should be noted that LWA TV itself does not allow real time access to the actual data nor does it store any of the individual real time images 3
24. last line except the minutes and hour crontab e The crontab function also can be used to temporarily stop and then restart the LWA TV application software at regular intervals to reduce network usage For example you could use a stop process at a specified time say 2200 in the evening and then a start process the next morning at 0700 The stop and start times can be set as required and are easy to change depending on observation activities Each hour the software is suspended will reduce network usage by about 91 MB It will be necessary to coordinate the start and stop times with the movie update time discussed above To use the suspension feature add the following three lines to the cron table using the cron table editor crontab e The lines shown here will start the program at 0700 and stop it at 2200 DISPLAY 20 0 7 python pi LWATV lwatv3 rpi py O 22 6 S DREeLL WL cSTD LD When using this feature the RPi must be running and connected to the network Simply delete the lines if you later change your mind about using the suspension feature WiFi and static IP Instructions for changing the RPi to a static IP address and adding WiFi access can be found on the internet but like a lot of things on the internet there is more useless than usable information I found these procedures worked for me these are the same links as given on the LWA TV website RPiWi Fi and RPilP The RPi works fine with both the Ethernet
25. mass and energy output E mc Over timescales of tens of thousands of years that energy migrates to the star s photosphere where it s emitted out into the universe as starlight There s only a finite amount of fuel in there and when stars run out the interior contracts and heats up often enabling heavier elements to burn at even higher temperatures and causing sun like stars to grow into red giants Even though the cores of both hydrogen burning and helium burning stars have consistent steady energy outputs our sun s overall brightness varies by just 0 1 while red giants can have their brightnesses vary by factors of thousands or more over the course of a single year In fact the first periodic or pulsating variable star ever discovered Mira omicron Ceti behaves exactly in this way There are many types of variable stars including Cepheids RR Lyrae cataclysmic variables and more but it s the Mira type variables that give us a glimpse into our Sun s likely future In general the cores of stars burn through their fuel in a very consistent fashion but in the case of pulsating variable stars the outer layers of stellar atmospheres vary Initially heating up and expanding they overshoot equilibrium reach a maximum size cool then often forming neutral molecules that behave as light blocking dust with the dust then falling back to the star ionizing and starting the whole process over again This temporarily neutral dust absorbs t
26. minutes After the Write operation is finished the memory card is ready to use in the RPi Be sure RFi power is OFF and insert the card Note Some micro SD cards and card readers are incompatible so it is best to install the micro SD card in a full size SD card carrier insert the carrier into the reader and then format the card and load the software image 48 Network Connection Error 2014 01 28 20 05 19 UIC 3 Figure 8 If there is a network connection problem the live globes are gray and warnings appear During normal operation the Error Downloading Image message may momentarily appear but it is nothing to worry about if it happens only occasionally Image 2014 W Reeve The RPi model B uses an ordinary push to insert pull to release slot connector whereas the model B uses a push to insert push to release slot connector When the RPi is powered ON the software will load and run automatically RPi console In order to make changes to the RPi setup described later in this section it is necessary to log into the RPi console This may be done from a Windows PC that is on the same network as the RPi or through a wireless or wired keyboard The RPi uses secure shell SSH for console communications so it is necessary to install an SSH client application such as PuTTY or TeraTerm on your PC if using the network connection To use SSH first determine the IP address assigned to the RPi by your internet router Procedure
27. of the test assembly when going from a coiled state to an uncoiled state It may also be noted that the behavior is essentially linear through 8 GHz Choosing an arbitrary frequency of 10 GHz the indicated phase change from an initially coiled state is 11 0 degrees If one considers that a 10 GHz continuous wave signal will cycle through 219 546 degrees over a 50 foot cable the 11 0 degree figure represents 0 005 of the assembly s phase length A high performance microwave cable assembly must possess excellent phase repeatability Phase Figure 1 Normalized phase repeatability refers to an assembly s ability to duplicate its original or response of uncoiled cable initial phase behavior when the cable assembly Phase Stability 50 ft Assembly Uncoiled has been flexed or disturbed then returned to its original unflexed or undisturbed uni 4 A E O00 state E T oS one a e A Tidd p an IJ es zm a 11 000 a 12 000 i 15 OH H m AR a of Lid i J i i 4 iti Fa IU lz l4 1b ti Frequency GHz 39 coiled state deg Change in loss from initial tolled state dB LELEI IEE weti I HO TI HI response of cable p r when returned to coiled state Phase Repeatability 50 ft Assembly Return to Coiled State Frequency Hz ae a 1a ooo Insertion Loss Stability 50 ft Assembly Uncoiled Frequency GHz Figure 2
28. other words just let the RPi run and never rebooted it If you suspect your WiFi connection confirm connectivity as described in the previous item Backup You will want to backup your memory card after any major changes You will need this backup if you corrupt the program so badly that it will not boot There are several ways to run a backup If you are a Windows user you can use Win32Disklmager the same program used to Write the image to the memory card in the first place However to backup you will Read the image This method reguires removing the SD card from the RPi 53 and then inserting it in a card reader connected to the Windows PC Be sure to shutdown the RPi before removing the memory card see next item Shutdown the RPi To avoid corrupting the RPi software the system must be properly shutdown before removing power just like a Windows PC This may be done from a keyboard connected to the RPi by pressing CTRL ALT F1 to invoke the console directly on the display or by using an SSH client on a PC Log into RPi at the prompts and then enter sudo shutdown h now or sudo halt The display will indicate the shutdown process All LED indicators except the red power LED on the RPi board will extinguish when the shutdown is complete Power may then be removed If you are at the console and change your mind before entering the shutdown commands press CTRL ALT F7 to return to LWA TV References and Web Links 7 Zip http w
29. pdf You can also open a template to write your article http www radio astronomy org publicat RA JSARA Article Template doc Let us know if you have guestions we are glad to assist authors with their articles and papers and will not hesitate to work with you You may contact your editors any time via email here editor radio astronomy org Please consider submitting your radio astronomy observations for publication any object any wavelength Strip charts spectrograms magnetograms meteor scatter records space radar records photographs examples of radio freguency interference RFI are also welcome Guidelines for submitting observations may be found here http www radio astronomy org publicat RA JSARA_ Observation_Submission_Guide pdf Tentative Radio Astronomy due dates and distribution schedule Issue Articles Radio Waves Review Distribution Jan Feb February 12 February 20 February 23 February 28 Mar Apr April 12 April 20 April 25 April 30 May Jun June 12 June 20 June 25 June 30 Jul Aug August 12 August 20 August 25 August 31 Sep Oct October 12 October 20 October 25 October 31 News Mark Your Calendar 2015 Annual Conference Keynote Speaker Announced Vice President Tom Hagen announced today that Duncan Lorimer from West Virginia University Department of Physics and Astronomy has agreed to be the Keynote Speaker at the 2015 Annual SARA Conference to be held June 20 to 24 at the National Radio Astronomy
30. with permission from the December 2012 issue of In Compliance Magazine www incompliancemag comhttp www incomliancemag com This article addresses phase stability loss stability and shielding effectiveness in cable assemblies exceeding 20 feet Stability and shielding effectiveness behavior of long length assemblies are not well documented and lack standardized test procedures Phase and loss repeatability is addressed within this writing as a sub topic of Stability This document offers basic performance information pertaining to one specific type of microwave coaxial assembly which would typically be used in a test environment where occasional coiling uncoiling and random movement would occur Information contained within this piece is for reference purposes only and does not constitute a performance specification for any particular microwave RF cable assembly TEST SUBJECT Testing was performed on a microwave RF Test assembly 50 feet in length having the following specifications Cable Type internally ruggedized enhanced phase stability cable 18 GHz maximum frequency Nominal cable outer diameter 0 305 inches Stranded center conductor Minimum bend radius 1 0 inches Crush strength 250 lbs linear inch Connectors Connector A side precision 3 5 mm pin Connector B side precision 3 5 mm socket Assembly Length 50 feet measured from connector A side reference plane to connector B side reference plane TEST EQUIPMENT Te
31. work has been with Landsat and AVHRR Satellite data classifying agriculture crop land images for the US Department of Agriculture I ve been a SARA member for about 15 years and started out recording VLF data in 1999 now do much of the analysis for the Solar lonospheric Detection SID detections for the American Association of Variable Star Observers AAVSO Solar Section which is responsible for collecting and recording the Very Low Frequency VLF SID events caused by solar flares http www aavso org solar sids SID event submissions come from VLF radio solar observers around the world 27 Cheap and Simple Demonstration Radio Interferometer By Kenneth Kornstett Abstract A demonstration interferometer is described with both data and simulation results presented The initial objective was an inexpensive and simple interferometer to detect interferometer fringes Design decisions assumptions and mistakes are documented 1 Introduction The title for this paper comes from the SARA Google Group where an interesting comment was found just to get interferograms out the other end cheap and stupid works remarkably well 1 Hence the title for this paper comes from that statement but with the word simple used for stupid Also mistakes to avoid are included to help other experimenters create a better system by avoiding my mistakes That is similar to Cliff Bates A Basic Primer on Setting up an Amateur
32. 1 2 index htm 19 S57RA SIDI photo gallery http lea hamradio si s57ra index php radio astronomy galer 20 S57RA SIDI recorded data http lea hamradio si s57ra index php radio astronomy radio sources recorded with sidi 21 EGNOS wiki http en wikipedia org wiki Egnos 22 ERAC VLBI Yahoo group https groups yahoo com neo groups erac vlbi info 17 List of figures fig 1 fig 2 fig 3 fig 4 fig 5 fig 6 fig 7 fig 8 fig 9 fig 10 fig 11 18 SIDI v 1 0 hardware Radio source in Cygnus detection with SIDI v1 0 Center peak is DC Cygnus A is the small peak to the left red arrow SIDI v 1 1 hardware SIDI v 1 0 Synthesized radio image of GPS satellites The double decker DSP_FFT award SIDI v 1 2 hardware Raw fringes from recorded file The declination value shown is wrong it was about 1 degree Fringes after a 13mHz slowdown Fringes after slowdown averaging Sun burst on 02 Apr 2014 24h spectrogram 9 files averaged Born 1959 in Ljubljana then Yugoslavia Graduated 1984 from the faculty of electrical engineering University of Ljubljana Until 1986 worked in the antenna laboratory at the faculty on antenna measurement automation etc 1986 1993 worked at the ISKRA company developing ESM and ELINT systems for the Yugoslav army air force until 1991 then worked on telecom microwave links Since 1993 with the MOD Slovenia as an expert in radars and related systems Leisure activit
33. 1197 df 9354 027 p value 0 9047 95 percent confidence interval 0 0402109 02042 76506 sample estimates mean of x mean of y O 2 00L 537806 0200193 50 6 From the two sample t test Welch it looks as though the VLF SID Events frequency counts are NOT as anti correlated as are the sunspot group counts Here s another statistical test Pearson s product moment correlation data VLF and CR t 1 2899 df 6296 p value 0 1971 95 percent confidence interval U 008447782 0 040935 190 sample estimates cor 001625362 TE YF at ae ae a TE TF TF TF Ae ea TE TF Hee E E E E E E E E E EEE data group and CR t 1 4756 df 6296 p value 0 1401 95 percent confidence interval 0043272259 006106656 sample estimates cor 0 01859412 The Pearson s correlation test also shows that the SID Events data are not as anti correlated negative correlation as the AAVSO group counts data Figure 6 shows regression lines drawn through the pairwise scatter plots 25 45 55 65 75 440000 448000 25 15 cosmic_ray 45 55 65 75 440000 448000 05 15 25 Figure 6 looking at both left and right side of the diagonal scatter plots the VLF SID data do not show as negative a slope as the sunspot group active region regression line 0 5 10 15 20 25 aavso_g 0 5 10 15 20 25 Ww M 65 cosmic_ray 55 45 45 55 65 75 Figure 7 shows a blow up of the slopes for data tes
34. 2500 mi 1450 SE 255 4 1400 100 200 300 500 600 700 800 400 Time s Sun observation off on off mode dB Figure 3 The same data as in figure 2 but now expressed in dB as calculated by the specification for the AD8307 logarithmic detector Intensity dB o MN 5 am 100 200 500 500 600 700 800 400 Time s Sun observation off on off mode linear Fituese 10 Mar 6 6x10 2 E 8 eot Figure 4 Still the same data but now the plot is 5 converted into a linear scale by 2 Z 2x105 Oo 100 200 300 200 600 700 800 400 Time s When we finally get the data in linear form we can apply statistical functions to it To get the signal itself that is Tsys We need the average of the hot part Ihot and the average of the cold part loia To get the rms noise of the hot part we calculate the standard deviation of it leading to Ono In my case based on Callisto observing the sun at 1152 MHz get 40286 45055 _ 16 0 AE CP oo 2 725 7 As shown above we expect from theory an SNR of 17 3 which is 7 5 higher than the measured value but acceptable This error can be explained by non ideal construction of the time constant T in the integration circuit as well as imperfect Knowledge of the bandpass filter s eguivalent noise bandwidth Conclusion With a simple hot and cold measurement the sensitivity of a nonlinear receiver can be checked with res
35. A i Ta r i ma n sig ife red y m E 1 Ca P a okt Figure 7 Left This view looking down the driveway was taken shortly after the ten helix posts were installed Right The next day installed pressure treated outdoor wood beams for the building to rest on This view is looking up the driveway toward the original Cohoe cabin The foundation was lined up with the driveway so the building could be delivered on a trailer Images O 2014 W Reeve 61 TW i ine Figure 8 Upper Observatory building resting on its foundation the day after delivery The stairs have not yet been built but all other exterior work is completed The green metal roofing sheds snow very easily so an ice bridge will be built between the tower and building cable entrance to protect the coaxial and rotor control cables to the tower Lower left View of the observatory building from the end of the driveway The tower can be seen on the right Lower right Inside view of unfinished building looking toward the front The roof is made from built up trusses and the cavities between floor joists are sealed and insulated The usable interior floor space is approximately 250 ft and walls are 8 ft high Images 2014 W Reeve 6 Next Step The next step consists of indoor work including bathroom construction and installation of associated plumbing electrical wiring and wall and ceiling insulation an
36. LWA TV software uses mountain daylight time MDT but both the time zone and movie cache update time can be changed See Date time and time zone in section 5 for these and a method to suspend the software at night or outside normal observation times to reduce network usage 47 Latest LWATV Image image Description 2014 03 07 00 25 40 UTC ee ie These breages show the sky albowe ne first LA sigder Bia The update aver iome saconcs and Itig mage isni uO dso nant inow Es pribati Deca We we iuning laa girwcnred amser 4eich we fer mare leo JE Bas Pe Tub Sey rat LC tl PROM al i sedan The lef shows the total intensity ad the kemat ol cr cat pobrized redo wi can 5EP Ce aera Cee O Tee PTS Oer F LTE wher swich Mean Tir BG WE ATS ail is gl aS ee Hugem ferrin ip nr ant a letical galima abi i ate there wl sometre ter than hese Ape P Eg I FE ESS ADs JME radia frequency Brief m ai rr a z eg other men ine sky Th a ea e ira aa Mm es gan ch m p Hipag OT By pege HF DT oe YN H aa he a PS Clore Ray SET A git 5pmethrg mew fares from Hot jupiter ar magnetara m Te Ceres to graa ay Uusi a sre To nA and LI ceed Lur COIFERLITETH mill DE mMmanbornig hes mines 3 let os now when Sor Bi rF r A3 A The OWAL Site Located By the VLA Movie for February 27 2014 Figure 7 LWA TV screen The live image at top left shows one or two circles depending on the current LWA operating mode When LWA is setup for beam pointing
37. RA Journals from 1981 through 2013 SARA Mentor CD compiled by Jim Brown i SARA Navigator IBT CD and DVD compiled by Jon Wallace Prices US dollars including postage Members Each disk 15 00 Disk 1 year membership extension 30 00 Non members Each disk 25 00 Disk 1 year membership 30 00 Non USA members Each disk 20 00 airmail Disk 1 year members extension 35 00 Already a member and want any or all of these CD s or DVD s Buy any one for 15 00 or get any three for 35 00 SARA Store http www radio astronomy org e store 68 SARA offers the above CDs DVDs printed Proceedings and Proceedings on CD and other items at the SARA Store http www radio astronomy org e store Proceeds from sales go to support the student grant program Members receive an additional 10 discount on orders over 50 US Payments can be made by sending payment by PayPal to treasurer radio astornomy org or by mailing a check or money order to SARA c o Melinda Lord 2189 Redwood Ave Washington IA 52353 SARA Online Discussion Group SARA members participate in the online forum at http groups google com group sara list This is an invaluable resource for any amateur radio astronomer SARA Conferences SARA organizes multiple conferences each year Participants give talks share ideas attend seminars and get hands on experience For more information visit http www radio astronomy org meetings Facebook Like SARA on Fac
38. Reviewers Whitham Reeve amp Stan Nelson Most readers who have been involved in radio astronomy will recognize the author s name Francis Graham Smith Smith who along with Ryle discovered Cygnus A in the 1940s has written numerous books over the years In Unseen Cosmos Smith is both entertaining and explanatory with very little mathematics Smith shares with us historical current and future views of the future from his perspective as a pioneer in radio astronomy For the beginning amateur radio astronomer this British book should give you a good grasp of the terminology and concepts in mostly laymen s language While the book does not discuss amateur radio astronomy specifically it would be a valuable starting point for the amateur Smith s book is broken up into 11 chapters The first chapter Radio Noise from Space discusses the early pioneers Karl Jansky and Grote Reber The next 10 chapters cover topics about the sun and planets our galaxy cosmic rays radio galaxies and guasars supernovae and pulsars pulsar clocks and relativity cosmology dishes and arrays The final chapter addresses the major new radio astronomy arrays called LOFAR ALMA and SKA arrays We found figures such as 11 and 12 on pages 27 and 28 a little confusing due to the use of a and b that don t correlate well with the two illustrations The print is large with decent line spacing for easy reading The book is well illustrated with black and white photos an
39. West Virginia www radio astronomy org meetings Do you have an event to share with SARA members Send information to editor radio astronomy org to be included in the next issue L to R Visitor Bill Dean Bill Lord and Jim Thiemanat 2014 Dayton Hamvention 2015 SARA Western Regional Conference Palo Alto California USA on 20 22 March 2015 The 2015 SARA Western Regional Conference will be held at Stanford University in Palo Alto California on Friday Saturday and Sunday 20 22 March 2015 The meeting will include a visit the Kavli Institute for Particle Astrophysics and Cosmology KIPAC Call for papers Papers are welcome on subjects directly related to radio astronomy including hardware software education and tutorials research strategies observations and data collection and philosophy If you wish to present a paper please email a letter of intent including a proposed title and abstract to the conference coordinator at westernconference radio astronomy org no later than 31 December 2014 Be sure to include your full name affiliation postal address and email address and indicate your willingness to attend the conference to present your paper Submitters will receive an email response typically within one week Presentations and proceedings In addition to presentations by SARA members we plan to have speakers from the Stanford University faculty and possibly KIPAC Papers and presentations on radio astronomy hardware
40. acture took away from my time at Cohoe However as described in more detail in the following sections the building is in place and ready for interior work and thus the major construction activities are done 2 Driveway contracted a local company to build a 100 ft driveway from the existing built up area to the new building location adjacent to the tower described in Parts 2 and 3 The soil at the site consists of about 6 in of peat on 2 to 3 ft of red sandy clay top soil and hard compacted sand and gravel to a depth of 15 ft the latter being very good road foundation material For the driveway the top soils were removed and replaced with imported sand and gravel Starting at the built up area the excavator removed the roots and top soil and placed them aside figure 1 A dump truck then emptied a load of sand and gravel material into the excavated area The dump truck stayed inplace while the previously excavated top soil and root masses were loaded into the empty dump figure 2 When full the dump truck left to dispose of the material and pick up a new load of sand and gravel Meanwhile the new material was spread by a small tracked front end loader This process was repeated for the full length of the 10 ft wide driveway figure 3 The job required about 12 dump truck loads and including the utilities described in the next section 1 5 d work time 56 Figure 1 An excavator with a wide bucket removes the top soils from the ha
41. adio Astronomy as we get closer to the conference date Please contact conference coordinator David Westman if you have any questions or if you would like to help with the conference westernconference o radio astronomy org RASDR2 Update The RASDR development team and Beta testers have been hard at work testing the new RASDRViewer 1 2 software with the RASDR2 hardware The new RASDRViewer not only offers Continuum for detection of radio astronomy sources plus spectrum analysis for HI detection in our Galaxy and the ability to detect OH and other radio spectrum The RASDRViewer 1 2 software has performed very well during the Beta test and is quite stable One of the key to differentiators of RASDR is its ease of use Just add an antenna LNA and coax along with a Win PC and you have a working radio telescope Paul Oxley is currently looking to add Pulsar detection to the RASDRViewer If this can succeed with the small radio dishes amateurs use it will herald a new era of amateur radio astronomy The RASDR hardware is ready to go the team is in the process of finalizing the changes to the boards in order to reduce cost without giving up any function The team is currently finalizing the final steps in manufacturing RASDR2 and you may expect an announcement of RASDR2 availability and pricing by mid November we are planning on having the RASDR hardware available in the second guarter of 2015 with final pricing which we expect to be under fiv
42. aid out in a large U shape across the laboratory floor The connection at port 2 was then restored and sparameter data was collected This data set was labeled Uncoiled Data The cable assembly was disconnected from port 2 of the network analyzer and again coiled with loops approximately 1 foot in diameter Re coiling was performed in the same direction as was done when the cable assembly was initially coiled The connection at port 2 was once again restored and s parameter data was collected This data set was labeled Return Coil Data The uncoiled and return coil s parameter data were normalized by the initial coil s parameter data set Phase and loss information was extracted from the normalized s parameter data By choosing the initial coil data set as a baseline one may observe how the phase and loss characteristics of the cable assembly deviate from a known state Any deviations are assumed to have resulted from physical manipulation of the cable assembly under test SHIELDING EFFECTIVENESS TESTING Shielding effectiveness testing was accomplished through the use of Gore s own mode stirred chamber Tests were conducted from 1 0 to 18 0 GHz 1 GHz steps in accordance with MIL STD 1344A method 3008 The noise floor of the test environment was verified before each test as was instrument dynamic range Efforts were made to keep the bulk of the test cable and its connectors within the working volume of the mode stirred
43. ame simulations For example the 12 GHz simulation is over the real data peak at point A but the 10 GHz simulation is close to the 33 peak at point B In Figure 8 shifted the data curve one point to the right and the 10 GHz simulation lined up more over the two points A and B 10 GHz simulation with 10 June 2010 data shifted one point to right C Xi tt i TiK a y 4 Fa 4 i P Y T i 4 y 1 i Fi j 1 if a _ a N i 2 j S i i 2 i l i a i i i i aT j i i i i 1 j i a hi 1 3 i i i i i i i j i j i i UR 1 j i I i i L i 4 i j l m i i i i E a L i i i i i i att oe i i i Ly iy r l i i i Y i y i 7 ra T NR Y aa k Mr ey LU T r r ne e T ae z ee T r H E N 4 i IG AJ 24 Pris Fa F ET ei Fn Tr T ix gt i Time 15 second points Figure 8 10 GHz Simulation with 10 June 2010 Data Curve Shifted One Point to Right The data is still the red curve with the solid black curve being the 10 GHz simulation curve Next the declination calculation will be addressed 3 Declination calculations My original declination calculation was bad for two reasons First I used too high a freguency for the wavelength value Upon gra
44. and WiFi connections enabled and it is not necessary to unplug one when using the other You will need a WiFi dongle figure 12 I purchased one from Adafruit It should be remembered that a wireless dongle derives power from the RPi USB port and this power is in addition to that reguired by the RPi itself The dongle should be plugged into the USB port before power is applied to the RPi otherwise the RPi will reboot because of the momentary voltage drop on its power bus This is a design deficiency in the RPi t Figure 12 WiFi dongle provides wireless access and uses one USB port found the distance from the RPI to the wireless access point to be surprisingly good gt 3 m in spite of its very small antenna Image source unknown The following commands can be used to check the quality of the wireless connection after it has been setup sudo iwlist wlan0 scan or sudo iwconfig Downtime Sometimes the LWA TV does not seem to be working or the display does not properly render the archive movies or live presentation You may see Error Downloading Image and Network Connection Error on the display for brief periods This does not appear to be a fault with the RPi but possibly with the network connection or the UNM server and related maintenance activities It also may occur during the transition from normal view to beam pointing view The outages do not last long maybe tens of minutes at most and always self corrected in
45. and the monitor A keyboard with or without a mouse might be handy but is not necessary No changes are required to the RPi platform but it should be installed in an enclosure A Secure SHell SSH terminal generally is used to communicate and manage RPi from another computer on the same network This is described in more detail in section 5 Figure 4 HDMI to VGA converter allows the RPi to be used with most computer monitors The ones shown here cost about 10 USD The RPi reguires a full size HDMI connector seen on the left converter An adapter will be needed If the converter has a mini HDMl connector as seen on the right converter Image 2014 W Reeve The power requirements of the RPi are modest about 5 W for the model B and 3 W for the B assuming no current is being drawn from the USB ports Because these powers are more than supplied by a standard USB port on a PC it is necessary to use an external power supply or power adapter If no USB peripherals are used the RPi can be powered by a well regulated low ripple electrically guiet power source rated gt 1 0 A at 5 0 Vdc gt 5 W If the RPi USB ports are to supply power to peripherals then a 10 W or higher power source should be used Using a poor guality power supply will lead to unreliable operation so be sure it meets these reguirements One of the most common problems users have with the RPi is inadeguate power supply current To minimize electrical noise it is recommended t
46. arted in Radio Astronomy 72 Education Links 74 Online Resources 76 For Sale Trade and Wanted Sara Polo Shirts 77 For sale 77 Radio Waves President s Page Thank you to all SARA members who attend the conferences contribute to the Journal and support this organization Our recent Green Bank conference was educational and enjoyable many thanks to planners who booked two Nobel laureates and members who presented papers We hope you ll make plans to attend these upcoming conferences e The 2015 Western Conference will be held at Stanford University in Palo Alto California March 20 through the 22 SARA is soliciting papers for presentation at the conference More information is in this Journal as well as on line at http www radio astronomy org meetings e The Eastern Conference is set for June 21 to June 24 2015 at the National Radio Astronomy Observatory in Green Bank West Virginia Dr Duncan Lorimer Ph D will be our keynote speaker He s an astronomer at West Virginia University astro wvu edu people dunc More details will be made available on line at http www radio astronomy org meetings and in upcoming Journals It may seem a long way off but we need to be thinking about officers Secretary and Treasurer and directors 2 Directors and 2 Director At Large nominations If you are interested in serving as secretary treasurer or director please let me know Also take a minute to look at the responsibilities and d
47. as the most influence on modulating cosmic rays reaching the Climax Neutron counters The VLF SID Events from solar flares or the sunspot active regions counted as groups by AAVSO visual observers It will take some statistics to determine which has the tightest anti correlation If we graph cubic spline fits to these different data we can see how similar and different they are for example the SID Events data are recording the effects of solar flares on the Earth s ionosphere Figure 3 And the sunspot group counts measuring white light active regions are observations made from small telescopes These active regions may or may not cause solar flaring however they do seem to show a more distinct maximum and minimum Figure 4 aavso_VLF smoothing splines cc I co u ha gt O 8 8 co cc C CO 440000 444000 448000 452000 jdt Figure 3 shows how the daily frequency counts of VLF SID events which seems to have a lot of variability from cycle 20 thru cycle 23 23 aavso_g smoothing splines o a o o o o o o o OO o_op oD Ei ooo aD O O TD GOD TaD CDD CORED CHED TRD O ib HED TE i o h o D w gt o w o 440000 444000 448000 452000 jdt Figure 4 shows how the group counts begin to scatter during the peak in solar activity And these 4 solar cycles show bi modal peaks The Climax cosmic ray flux data also shows some variability from solar cycle to solar cycle but not as much as the SID
48. beam width The wide beam width was design decision 2 This brings up mistake 1 LNBFs had internal down conversion Down conversion meant a local oscillator is used to convert the frequency down to a lower frequency range If I used two LNBFs I would have to phase lock the two oscillators together to avoid losing phase information did not want to have to open up the LNBFs to get access to the two local oscillators to phase lock them wanted to use off the shelf items when possible At this point made assumption 1 perhaps if only one antenna frequency was down converted then fringes could still be obtained if the other antenna signal was not down converted As suspected it worked For a signal source decided to use the sun design decision 3 The sun s RF signal would be stronger and make up for not using the dish which had gain too This brings up mistake 2 had forgotten that the sun has 11 year sun spot cycles and the quiet sun is not as strong signal wise as an active sun In low sun spot activity the sun s quiet signal would be weaker My next decision was what to use for a second antenna The LNBF down converted the frequency to around the 1 GHz range so would need an antenna in that frequency range to make an interferometer Fortunately had already made several working wire antennas VHF and UHF using welding rods decided to use a three element Yagi since had built and had been using a home made three e
49. c in 1999 and has worked with various groups including Gore s Signal Integrity Lab the Planar Cable Team and the Fiber Optic Transceiver Team For the past 10 years he has worked within the Microwave Cable team 41 LWA TV on the Raspberry Pi Whitham D Reeve 1 Introduction This article describes how to use the tiny and inexpensive Raspberry Pi computer with the Long Wavelength Array in New Mexico to observe celestial radio sources in near real time LWA1 figure 1 The application was developed by the University of New Mexico UNM as part of LWA Education and Public Outreach It is a good way to Abbreviations DHCP Dynamic Host Configuration Protocol DVI Digital Visual Interface GUI Graphical User Interface HDMI High Definition Media Interface IP Internet Protocol LAN Local Area Network LWA Long Wavelength Array RPi Raspberry Pi UNM University of New Mexico VGA Video Graphics Array become familiar with the LWA LWA TV and the Raspberry Pi all at the same time The LWA TV program does not allow user control only observation and it runs out of the box with no user programming whatsoever Figure 1 The Long Wavelength Array in New Mexico consists of a forest of 257 crossed dipole tied fork antennas Beams are formed through signal processing to observe specific celestial radio sources or areas of the sky Image 2014 W Reeve One of the advantages of the approach described here is tha
50. ce April 2014 NOAA s Space Weather Prediction Center SPWC has sought feedback from stakeholders and customers via a survey on the beta release of the new website We will continue to respond to feedback from stakeholders and customers regarding issues of content or behavior of the new site as we go through this transition to operational status For questions or feedback regarding this action please use our feedback form http origin WWw swpc noaa gov content contact us or contact Dr Steven Hill Space Weather Prediction Center Boulder CO 80305 303 497 3283 steven hill noaa gov Of particular interest to SARA members is one of the dashboards designed especially for soace weather enthusiasts http origin www swpc noaa gov communities space weather enthusiasts Frequency Agile Solar Radio Telescope http www ovsa njit edu fasr Would you please make up your mind Voyager spacecraft might not have reached interstellar space http news agu org press release voyager spacecraft might not have reached interstellar space See also So Where the Heck IS Voyager 1 Anyway http time com 3023509 where is voyager 1 And finally Is Voyager in Interstellar Space http www pddnet com news 2014 08 voyager interstellar space et_cid 4111701 amp et_rid 210447177 amp location top Science Graphic of the Week Jupiter s Huge Crazy Magnetic Field http www wired com 2014 07 science graphic jupiter magnetic field Solar
51. computer controls the ADC and sends the digitized data to the laptop computer I changed the sampling time from 1 minute to 15 seconds in the microcomputer software for the cheap and simple interferometer The laptop stored the time the data was received time stamped and the interferometer data in a file use a six line header in that data file to store details about the data run because system configuration often gets fuzzy over time I also keep a log of the configuration details such as number of amplifiers antenna baseline weather conditions attenuation if run was good or bad and etc The data was 32 plotted using a spread sheet Data processing was accomplished using 3 point smoothing Later would use averaging and simple low pass filtering in software By using the Ku band intensity radio telescope was able to build a working interferometer cheaply The only cost to build the interferometer system was the signal summer about 15 including shipping plus about 32 for several short RG 6 coax cables had extra surplus brazing rods that used to build the Yagi antenna The other parts came from my tool box If you need a satellite finder one can be obtained for less than 10 plus shipping while the inline amplifiers can be purchased for as little as 5 plus shipping With the cheap and simple system described the data obtained will be compared to simulated data 2 Fringe data obtained compared to simulations The
52. d diagrams There are 17 color plates in the middle of the book We both found the separation between B W illustrations and color images a little annoying especially when the text referred to both to explain a phenomenon It would have been nice if all illustrations were presented in order However publishers often bind the color images in the middle of the book separately to keep production costs down This book is a very broad overview that mentions every aspect of professional radio astronomy i e big science but sometimes too briefly A few explanations were so brief they were difficult to follow but it is difficult to explain extremely complex physics in a non technical way However for the most part the book is well written and easy to follow One underlying theme of everything written about radio astronomy including Unseen Cosmos is that discoveries are enabled by new technology not just bigger telescopes Radio astronomy really took off after WWII mainly because lots of state of the art radio equipment became available cheaply But it wasn t long before new discoveries could be made only by continually advancing the state of the art There is a relatively comprehensive and quite interesting discussion of the several different types of pulsars including the discoveries made by Joe Taylor and Russel Hulse Taylor gave a very interesting talk at the 2014 SARA summer conference on these discoveries 64 In one section on page 71 Sy
53. d frame construction and is 24 ft long x 12 ft wide plus a 4 ft porch figure 8 It was prebuilt to order by a company called Sterling Supply in the town of Sterling about 35 road miles away When ordered the building specified window sizes and locations and door location and with finished exterior but unfinished interior My order also included exterior sheathing below the floor joists and foam insulation in the joist cavities After completed the foundation Sterling Supply delivered the building to Cohoe on a special trailer The trailer was maneuvered into position and the building lowered onto the foundation beams The delivery truck and trailer were on site lt 30 min was unable to be on site during delivery so have no pictures of the process The main source of heat will be a small air tight wood stove which will be installed when the interior is finished in summer 2015 The stove will be used only when the observatory is occupied and the inside temperature is uncomfortably low The observatory radio equipment will be installed in a cabinet and self heated 60 4 0 24 0 Dubie cissi e dimension nduding Lisplabe Figure 6 Plan view of the foundation showing the post and beam structure and building walls Additional strength is provided by beams in the building floor structure not shown Image 2014 W Reeve Re ie E m gt a S a nl z L N uh a eE E Ti t 5 a a d i ae
54. d wall floor and ceiling finishing 62 7 References Reeve1 Reeve2 Reeve3 Reeve4 8 Units of Measure Conversion Reeve W Radio Freguency Interference Survey at Cohoe Radio Observatory Alaska Radio Astronomy Society of Amateur Radio Astronomers September October 2013 Reeve W Cohoe Radio Observatory Alaska Part 2 Guyed Tower Foundation Construction Radio Astronomy Society of Amateur Radio Astronomers November December 2013 Reeve W Cohoe Radio Observatory Alaska Part 3 Guyed Tower Installation Radio Astronomy Society of Amateur Radio Astronomers January February 2014 Reeve W Cohoe Radio Observatory Alaska Part 4 Callisto Antenna System Radio Astronomy Society of Amateur Radio Astronomers May June 2014 Many unit converters can be found online http www digitaldutch com unitconverter volume htm but for convenience conversions of the non metric units used in this article are shown below 63 Convert from acre inches in feet ft mile mi pound Ib To Multiply by sguare kilometer km 0 004 millimeter mm 25 4 meter m 0 305 kilometer km 1 6 kilogram kg 0 454 Book Review Title Unseen Cosmos the universe in radio Author Francis Graham Smith Publisher Oxford University Press ISBN 978 0 19 966058 2 Date Published 2013 1 edition Length 238 pages chapter notes and index Status See text Availability Hard cover Amazon USS34 95
55. e Eimmc cai AC Power Adapter z DEGAU s TD o LESU rr CMI Figure 6 Block diagram and equipment list for the RPi when setup for LWA TV See text for description of each item Before applying power to the RPi make all connections and turn on power to the monitor or television set Image 2014 W Reeve When connected LWA TV downloads a daily average of approximately 25 kB s 91 MB h or 2 2 GB d The internet traffic is split between the real time images and archived movies The LWA station processes the data and prepares images in near real time The LWA TV GUI checks for and downloads a new image every 5 s Each image includes the total radio energy received during the 5 s interval so transient emissions lasting less than 5 s are recorded The images are about 120 kB each so the average network traffic load is about 24 kB s The archived movies are downloaded in the evening and are usually around 100 MB each Downloading uses whatever internet bandwidth is available If your internet service has download limits and imposes penalties when exceeded it would be wise to monitor your usage closely If you want to reduce the internet usage overnight or other times you can simply unplug the Ethernet cable rather than shutting down the RPi If you use a wireless network connection you will need to use a software method to stop network usage The LWA TV application updates the movie archive cache at 1830 in the time zone used by the RPi By default the
56. e hundred dollars 500 00 For more information on RADR2 please take a look at http radio astronomy org rasdr We are planning on building a minimum of one hundred units which gives us a good price point for wholesale purchasing of the components and are asking for a one hundred dollar 100 00 deposit Please contact the SARA Treasurer treasurer radio astronomy org for methods of paying the deposit Many thanks to the SARA Board and members who helped make this project a success The RASDR Team Feature Articles SIDI the Simple Digital Interferometer Marko Cebokli S57UUU s57uuu hamradio si Reprinted by permission of the British Astronomical Association Radio Astronomy Group The RAGazine Vol 2 Issue 1 Aug 2014 SIDI is my attempt at a contribution to the ERAC s ALLBIN European Radio Astronomy Club Amateur Linked Long Baseline Interferometer Network project 1 whose main goal is to group several amateur radio telescopes into a VLBI very long baseline interferometry capable system started working on it around 2002 Currently in its third version v1 2 capable of detecting radio sources down to about 1 Jy with two 3m dishes at 1420 MHz Here describe the philosophy behind it the history of its development and some results obtained with it 1 Introduction Before starting with the development of SIDI spent a lot of time thinking trying to answer the question what is the simplest high performance VLBI capable in
57. e supplies the power from the power inserter The cable with the yellow connector is a RCA audio cable which connects the satellite finder meter to the digitizer A picture of the digitizer is shown in Figure 5 and the digitizer schematic is shown in Figure 6 31 4 Figure 5 Picture of Digitizer The digitizer consists of an interface circuit an Analog to Digital Converter ADC chip and a microcomputer Notice the breadboard and 9 volt battery The RCA cable is connected to the satellite finder meter and the RS 232 cable transmits the digital data from the digitizer to the laptop computer um ellibe Endrer bly E B HD m L 4 d eee a dTe O Bae ad FETTET Jin FILE z o 2 oM Mn WM mat RE CHD Et AD Il Figure 6 Digitizer Schematic The satellite finder meter was interfaced to the digitizer through an inverting operational amplifier The gain was selected to produce five volts output when the satellite finder analog meter was at full scale The output was fed to a buffer amplifier to avoid loading effects on the ADC chip input Only two of the four operational amplifiers of a cheap LM324 were used The ADC chip was a cheap 8 bit integrated circuit which had a maximum input of five volts The microcomputer board converts the 9 volt battery voltage to five volts for the BasicStamp 2 microcomputer the LM324 amplifiers and the ADC chip The LM324 only uses a single 5 volt supply The micro
58. ebookhttp www facebook com pages Society of Amateur Radio Astronomers 128085007262843 Twitter Follow SARA on Twitter radio astronomy1 What is Radio Astronomy This link is for a booklet explaining the basics of radio astronomy http www radio astronomy org pdf sara beginner booklet pdf 69 70 THE ELECTROMAGNETIC SPECTRUM Waeelength im oie wr gg gp hn ikti ire ol a y l i i i S z al ry Fawn i ma ht roar cot waw rear Lal 1 WO ET AED N RANS WC ET Fyn a 2 RAF Cae EN YU Tis r l F wm To tot go po do po gol go w wo ol w ve pot ic mm ee den o Co 1o iki Administrative Officers directors and additional SARA contacts The Society of Amateur Radio Astronomers is an all volunteer organization The best way to reach people on this page is by email with SARA in the subject line SARA Officers President Ken Redcap president radio astronomy org 1 248 630 6810 Vice President Tom Hagen vicepres radio astronomy org 1 248 650 8951 Secretary Bruce Randall secretary radio astronomy org 1 803 327 3325 Treasurer Melinda Lord treasurer radio astronomy org 1 319 591 1130 Past President William Lord tod radio astronomy org 1 319 591 1131 Founder amp Director Emeritus Jeffrey M Lichtman Jeff radioastronomysupplies com 1 954 554 3739 Board of Directors Name Term expires Jim Brown 2015 Chip Sufitchi 2015 Carl Lyster 2016 Step
59. eded to write or modify an application Notepad is perfect for this purpose and is free Notepad but Windows Notepad will also work The advantage of Notepad is that it automatically formats and indents the code to make it easier to read and work with The main piece of software in the LWA RV GUI is lwaTV3rpi py about 16 5 kB of text Examining the code shows that it includes four command line switches or options which may be used to customize the GUI The program operates normally with its default settings and there is no compelling reason to change them except for experimental purposes Using these options reguires knowledge of the operating system and I will not discuss them further 4 LWA TV on Raspberry Pi The setup for LWA TV is very simple figure 6 By default the LWA TV GUI uses the wired network interface Ethernet built into the RPi and acguires a network IP address automatically using dynamic host configuration protocol DHCP You can change this to a static IP address and add a WiFi interface However to eliminate many potential problems I recommend first running the LWA TV GUI in its default configuration to become familiar with it before making any changes See section 5 for some changes that you might find useful With the programmed memory card installed make all connections before applying power to the RPi 1 HDMI connection to your monitor or television set be sure it is turned on 2 Ethernet connection to
60. es in a secluded valley with the nearest neighbor a couple of km away behind a hill He does EME and is also interested in radio astronomy so all the following experiments with SIDI were done at his location There we were able to get the first fringes from SIDI using small antennas and simple S53MV style 0 4 dB NF low noise amplifiers 8 By changing the baseline we successfully measured the angular diameter of the Sun which could be received even with small 10 cm dipoles with reflectors With 16 dBi short backfire antennas 9 SBFA diameter 48cm Aef 0 17m2 we were just barely able to see the big Cygnus A source by using FFT fast Fourier transform on the fringes see fig centre peak is DC Cygnus A is the small peak under the red arrow Figure 2 2 8 dBediuv HERE ra TOE N TREA E AAG a Le eee CR a An 3 2 Version 1 1 The main goal of the second version was to see if the synthesizers in the satellite TV receivers are stable enough for interferometry have used tuners from old SkyStar computer DVB digital video broadcasting boards A few modifications were needed 10 like skipping the demodulator chip replacing the reference crystals with external inputs and changing the I2C address of one tuner Adding a couple of TBA120 old Siemens chip used in analog TV sound channels based limiting IF strips printed circuit boards with IF filters amplifiers limiters a TCXO temperature compensated crystal oscilla
61. eur astronomer looking for a new observing challenge or perhaps a student looking for a unigue science fair project Or maybe you re a K through college formal or informal educator looking for space science related projects to engage your students or ways to integrate engineering practices into your curriculum The largest coalition of amateur astronomy organizations in the world the Astronomical League AL and the National Radio Astronomy Observatory NRAO have teamed up with support from Associated Universities Inc to begin a new astronomy badge program You may have gazed at the stars enjoyed meteors streaking across the sky or looked at the massive planet Jupiter through a telescope but most people don t think about the invisible universe we miss by using our eyes alone Unlike most AL observing programs the new Radio Astronomy Observing Program RAOP encourages explorers of all ages to gaze to the cosmos and see the invisible radio universe Many objects in space e g the Sun Jupiter gas and dust in the Milky Way etc emit radio waves RAOP is designed to introduce and encourage observations in the radio part of the electromagnetic spectrum as well as the construction of various types of radio telescopes and observing instruments RAOP focuses on five major observing projects including 1 Space Weather 2 the Sun 3 the planet Jupiter 4 Meteors and 5 Galactic Radio Sources Each of the projects can be comp
62. first light for this interferometer was on 10 June 2010 The interferometer data and simulation data are plotted in Figure 7 The interferometer data curve is in red and the time was from 12 56 00 to 1 11 30 The astute reader may notice that the laptop time may have been slightly off intended to start the data run much earlier but a wire had come loose on the digitizer By the time got the problem fixed it was almost too late Mistake 3 was to use a breadboard rather than solder the digitizer circuit together Another mistake was to not continue the data run longer mistake 4 Notice that fringes are present For comparison on that chart three simulations curves are shown in black for 10 12 and 12 5 GHz with difference lines for the simulation curves The data sample rate was a sample every 15 seconds and the interferometer baseline was 1 485 meters The simulation beam width was 45 degrees The simulation curves were created using Chris Brown s interferometer program to create the simulation curve 6 Simulations vs 10 Jun 2010 data L20 m a a 100 Signal Simuleton value 10 Jun 2010 data Ku LNBF and 1 GHz Yagi interferometer Y 15 M 5 EI 5 5 59 55 l 55 An 7 ED Tame 15 second pomts Figure 7 2010 Ku LNBF and 1 GHz Yagi Interferometer Data and Simulation Data Notice on the graph that the data fringes at points A and B do not line up with the s
63. from the changing fringe frequency as the projection of the baseline is changing The vertical string of blobs through the left part of the Sun s crescent are the sidereal sources at the fringe frequency that corresponds to meridian transit with the given baseline The source shown in the preceding three figs is the topmost blob with a red core The solar burst is the bright horizontal line below the Sun crescent To be sure it is not ORM I checked the phase history and it is quite smooth fitting well with a source at the Sun s position The wide spread over the frequencies is caused by the strong amplitude variations during the burst s duration Figure 10 Combining files from multiple scans can improve the sensitivity Fig 11 shows the spectrogram of an average of nine files recorded end of March 2014 Figure11 On the fringe frequency there is almost no place without some activity meaning that we have increased the sensitivity to the point of reaching the confusion limit 15 6 Plans for the future In SIDI version 1 2 both the sampling clock and the tuner synthesizer references are derived from the same oscillator so it is already suitable for VLBI experiments So the very next thing planned is some experiments in this direction The plan is to use two SIDIs with free running oscillators and record a reference signal on one of the channels at each side For the reference signal plan to use EGNOS European Geostationary Navi
64. gation Overlay Service 21 This is a GPS like signal but transmitted from geostationary satellites For our application it has several advantages over normal GPS The same satellite is visible over a very wide area Does not rise and set can be locked on continuously Doppler correction is much smaller and simpler A directional antenna can be used for better S N On the hardware side the next step will probably be to put the sampling interface into a CPLD and make a small board that can be piggybacked on some commercial USB2 breakout board Next would like to replace the tin box tuners with single chip tuners like MAX2112 This would ultimately allow a small production run of SIDIs to be made because the clumsy tuner modifications wouldn t be needed any more Pavle has the idea of making fiber optic extensions using the dual fiber optical LAN cables That would permit connected mode operation with baselines up to a few hundred meters The receivers and samplers would be located at the antennas The uplink fiber would carry a reference frequency and tuner commands and the sampled data would be multiplexed onto the downlink fiber One Gb s optical transceiver modules are available cheaply and first experiments have shown that they are quite easy to interface For the latest news about SIDI development check at the ERAC VLBI Yahoo group 22 7 References 1 Project ALLBIN http www eracnet org workshop allbin html 2 Hans M
65. gi on the left and the summer The LNBF is on the right Notice that the LNBF does not have a dish and both the Yagi and LNBF are pointed straight up The LNBF has three feed horns and used the center feed horn the other two feed horns point off center The sun at that time of year would be in view of the two antenna beam widths Figure 2 Picture of the Cheap and Simple Interferometer Antennas Setup Notice that the Yagi antenna is mounted on a piece of wood with a pointed end It was cheap as the wood was really a left over wood stake The physical dimensions of the 1 GHz Yagi antenna are shown in Figure 3 30 Yagi dimensions element Ti tot mlmmamnt Llar SIE E rr rwELmcEcr apariy Figure 3 1 GHz Yagi Antenna Dimensions A picture of the power inserted and satellite finder is shown in Figure 4 The homemade power inserter bias tee has a switch to turn on power to the coax cable center wire for the upstream satellite finder LNBF and inline amplifiers The voltage was supplied by a lawn mower 12 volt battery I know that the LNBF should have a minimum of 13 5 volts but had used it with 12 volt before Later built a wall wart power supply with two reversed biased diodes to drop the voltage down to 13 5 volts The satellite finder is the small black box with a meter on the front The black coax on the left side of the satellite finder comes from the signal summer while the white coax cabl
66. hat ferrite beads be installed on the power cable figure 5 Figure 5 AC wall power adapter with 5 V 2 4 A 12 W output purchased at BestBuy One or more clamshell ferrite beads on the dc power lead help reduce radio freguency interference from the switchmode power supply This image shows one bead on the right with three windings of the power lead The Raspberry Pi uses a micro USB connector for power Image 2014 W Reeve 45 Software The RPi uses a software image that includes the operating system and applications The RPi image developed by UNM for the LWA TV GUI is based on a Raspbian distribution The software must be user installed on a memory card Installation is not difficult but it is done in a way that is not obvious to most Windows PC users UNM provides links to web pages with the necessary procedures see LWA EPO These procedures also are briefly listed in the Software installation part of section 5 To make this process a little simpler I can provide a preprogrammed micro SD card in an SD card carrier to interested readers See Contact information at the end of this article With this memory card the system truly is plug and play When running the LWA TV GUI software the RPi can be used only for that purpose However the software is written in Python and may be modified by users if they feel adventurous Python is an interpreted language and therefore is not compiled so nothing more than a text editor is ne
67. he visible light from the star and re emits it but as infrared radiation which is invisible to our eyes In the case of Mira and many red giants it s Titanium Monoxide TiO that causes it to dim so severely from a maximum magnitude of 2 or 3 clearly visible to the naked eye to a minimum of 9 or 10 requiring a telescope and an experienced observer to find Visible in the constellation of Cetus during the fall and winter from the Northern Hemisphere Mira is presently at magnitude 7 and headed towards its minimum but will reach its maximum brightness again in May of next year and every 332 days thereafter Shockingly Mira contains a huge 13 light year long tail visible only in the UV that it leaves as it rockets through the interstellar medium at 130 km sec Look for it in your skies all winter long and contribute your results to the AAVSO American Association of Variable Star Observers International Database to help study its long term behavior Check out some cool images and simulated animations of Mira here http www nasa gov mission pages galex 20070815 v html Kids can learn all about Mira at NASA s Space Place http spaceplace nasa gov mira en 66 Images credit NASA s Galaxy Evolution Explorer GALEX spacecraft of Mira and its tail in UV light top Margarita Karovska Harvard Smithsonian CfA NASA s Hubble Space Telescope image of Mira with the distortions revealing the presence of a binary companion l
68. hen Tzikas 2016 David James 2016 Curt Kinghorn 2015 Keith Payea 2016 Stan Nelson 2015 Other SARA Contacts All Officers Annual Meeting Coordinator All Radio Astronomy Editors Radio Astronomy Editor Radio Astronomy Contributing Editor Radio Astronomy Contributing Editor Radio Astronomy Contributing Editor Educational Outreach Grant Committee International Ambassador Librarian Membership Chair Mentor Program Navigators Technical Queries Webmaster 71 Email starmanjb comcast net ciprian sufitchi com ctlyster bellsouth net Tzikas alum rpi edu dave ogreenover net curtkinghorn gmail com kbpayea bryantlabs net stannelson cableone net Vice President Kathryn Hagen Christian Monstein Whitham D Reeve Stan Nelson Jon Wallace Tom Crowley Jon Wallace Tom Crowley David Westman Ciprian Chip Sufitchi officers radio astronomy org vicepres radio astronomy org editor radio astronomy org kathryn hagen gmail com monstein astro phys ethz ch whitreeve gmail com stannelson cableone net education radio astronomy org grants radio astronomy org membership radio astronomy org mentor radio astronomy org tomcrowley mindspring com technical radio astronomy org webmaster radio astronomy org Resources Great Projects to Get Started in Radio Astronomy Looking for a Winter Astronomy Observing Project Think Radio By Tim Spuck AUI STEM Education Development Officer tsouck aui edu Are you an amat
69. ichlmayr s wavelab http wavelab homestead com 3 A brief history of the IRO radio interferometer http www ukaranet org uk projects index htm doc1 4 1 4GHz NRAO VLA Sky Survey at vizier http vizier u strasbg fr viz bin VizieR source VIII 65 5 SIDI main page http lea hamradio si s5 7uuu astro sidi1 index htm 6 SIDI v1 0 http lea hamradio si s57uuu astro sidi1 sidi10 htm 7 SS3MV packet RTX http lea hamradio si s53mv archive p024 pdf 8 SS3MV LNA http lea hamradio si s53mv archive a136 pdf 9 SS3MV SBFA http lea hamradio si s53mv wumca sbfa html 10 SAT tuner modification for SIDI http lea hamradio si s5 7uuu astro sidi1 1 tuner htm 11 SIDI v1 1 description http lea hamradio si s57uuu astro sidi1 1 index htm 12 SIDI 1 1 first fringes http lea hamradio si s57uuu astro sidil 1 firstf index htm 16 13 SIDI 1 1 radio imaging http lea hamradio si s57uuu astro sidi1 1 imaging index htm 14 ERAC congress 2006 An introduction to SIDI http lea hamradio si s57uuu astro sidil 1 sidi intro pdf 15 Kimmo Lehtinen s SIDI presentation http www helsinki fi kklehtin seminar SIDI pdf 16 Alex Plaha forum posts http www astronomy ru forum index php topic 88024 0 html http www astroclub kiev ua forum index php page 100 17 The UUUSB board http lea hamradio si s5 7uuu uuusb index htm 18 SIDI v1 2 description http lea hamradio si s57uuu astro sidi
70. ies Have a HAM license since 1979 was active mostly on 10GHz EME under the call SS7UUU SETI league regional coordinator for Slovenia since 2000 In 2006 became a fellow of the ERAC for the work on SIDI Currently playing with radio interferometry together with Pavel S57RA How to Verify the SNR of a Receiver Based on the AD8307 Logarithmic Detector Christian Monstein HB9SCT As a designer of radio astronomical receivers I am always thinking of ways to prove that the signal to noise ratio SNR of a receiver fits with theory as introduced by John D Kraus Kraus 1986 in his radiometer eguation for a total power receiver om ly ae 1 where T js the system sensitivity or smallest change in antenna temperature that can be measured in kelvins Tsys is the system noise temperature also in kelvins B is bandwidth in hertz and is the integration time in seconds Equation 1 shows that the sensitivity of a radio receiver is proportional to the system temperature Tsys and inversely proportional to the square root of the bandwidth B times the integration time We can avoid any calibration in terms of noise temperature by rearranging equation 1 or dyr 7 Er 2 fays The ratio f is equivalent to the radiometer SNR therefore er Fhot 3 The system noise temperature T s in equation 3 can be found by a simple observation of a cold noise source such as a resistance termination at room temperature to obtain leoa and of
71. il monstein astro phys ethz ch Approximate location of Utopia s sun A planet about 10 million light years away in the Andromeda galaxy where they don t even have a word phrase for the term boy bands Cartoon by Nick D Kim Strange Matter net Used with permission 21 Using AAVSO VLF SID Events data the Climax Neutron Monitor records and AAVSO sunspot group counts to look into the anti correlation of the sunspot cycles and cosmic ray flux Rodney Howe The AAVSO Solar Section has collected data from sunspot observers since 1944 All these daily data are currently located on the NOAA NGDC site under American sunspot numbers http www ngdc noaa gov stp space weather solar data solar indices sunspot numbers american The question being asked here is not a new one it has been known for a long time 2013 Marius S Potgieter that cosmic ray counts from various observatories show an anti correlation of the cosmic rays with the 11 8 year solar cycle Data chosen here come from the Climax Neutron Monitor station in the Climax mine at Leadville Colorado ftp ulysses sr unh edu NeutronMonitor DailyAverages 1951 txt Climax Version 4 8 21 December 2006 National Science Foundation Grant ATM 0339527 Also there are Very Low Frequency VLF Sudden lonosphere Disturbance SID data that has been collected by the AAVSO VLF observers since 1958 http www ngdc noaa gov stp space weather ionospheric data sids aa
72. ingle bit sampling and maximum bandwidth This is also the main reason why SIDI uses none of the commercially available SDR software defined radio platforms like USRP universal software radio peripheral or RTLSDR TV dongles used as general purpose SDR receivers 2 4 Open system Another important decision made early on was to make SIDI fully open all of the schematics PCB layouts and software sources should be published on the web 5 under GNU or similar licenses People should be able to experiment with their own ideas for improvement and further development 3 History of SIDI development 3 1 Version 1 0 The main goal of this version was to see if the direct conversion one bit sampling correlation in software idea is viable I made a simple interferometer SIDI v1 0 6 out of some modules that I had lying around fig below from Matjaz Vidmar s packet radio system 7 The sampling was done with a DOS computer over the parallel port with a simple software loop that could run at about 600k samples per second The low pass filters on the IF boards were set to about 150 kHz giving about 300 kHz of bandwidth with I O sampling It worked on a fixed freguency in the 23 cm amateur band the LO local oscillator being a simple crystal oscillator followed by freguency multiplication This proved to be a problem as it was impossible to evade interference by changing the freguency Luckily my friend Pavle Reberc S57RA liv
73. lement Yagi to receive a 479 MHz UHF television signal know I could easily make a Yagi to operate at little over twice that frequency That was design decision 4 use an easy to build three element Yagi antenna Ideally an antenna should be followed by a good Low Noise Amplifier LNA By good mean a low noise figure The first amplifier after an antenna should have a low noise figure Without proof decided that early interferometers probably did not have good LNAs assumption 2 Thus decided to avoid the expense of a good LNA for the Yagi antenna Since the LNBF produced around 30 dB gain I decided to use inline amplifiers which are used with satellite TV systems because they were cheap and had several available knew that inline amplifiers have a high noise figure often oscillated and could impact the phase used two inline amplifiers with about 20 dB of gain each design decision 5 However from William Lonc s book knew that some gain differences between each antenna leg could be tolerated and still produce fringes 4 did try to keep the coax cable about the same length for both antennas to avoid introducing phase into the system 29 It should also be noted that inline amplifiers may have different bandwidths For example I have two inline amplifiers types one type has 40 to 2150 MHz while another type has 950 to 2400 MHz System bandwidth is important because as the bandwidth decreases so the signal
74. leted using various instruments that either individuals or small teams construct themselves or existing radio telescopes at the NRAO facilities or elsewhere Projects range from beginner to advanced levels and are open to amateur astronomers K through college educators and learners of all ages Participants earn a bronze certificate awarded by the Astronomical League for completing a single observing project a silver certificate and silver pin for completion of two projects and those who complete four observing projects are awarded the RAOP gold certificate and pin In addition to getting people to think about astronomy in a new light the RAOP can help bring together educators and amateur astronomers to address critical needs in science technology engineering and mathematics STEM education The U S Federal STEM 5Year Strategic Plan calls for the Nation to increase and sustain youth and public engagement in STEM by supporting a 50 percent increase in the number of U S youth who have an authentic STEM experience each year prior to completing high school In addition the Next Generation Science Standards NGSS call for the integration of engineering practices in science learning K through 12 Amateur astronomers are known for the excellent education and public outreach work they do and through the Astronomical League s 10 000 members and collaboration with NRAO the new RAOP will work to address these national priorities Begin e
75. lists 61 sources stronger than 10 Jy and 2206 sources stronger than one Jansky It is close to the 23cm amateur band There are quite a few radio hams that do EME earth moon earth on 23 cm and have big fully steerable antennas for the band Many of them are interested in radio astronomy It is close to the GPS band Being able to receive GPS with the same hardware with the same time base is very desirable for VLBI experiments n a guiet location bandwidths up to a few tens of MHz should be possible 2 2 Direct conversion In interferometry the local oscillators in all of the freguency conversions must be coherent To keep the hardware simple it makes sense to reduce the number of oscillators to the minimum possible one Once upon a time such direct conversion receivers were considered inferior but today a single I O in phase quadrature down conversion followed by a powerful DSP digital signal processing engine can have excellent performance and is the design of choice in many professional radio systems like GSM global system for mobile GPS etc 2 3 One bit A D analog to digital conversion The signals at the input of radio astronomy receivers are well below the noise level so sampling them with high precision doesn t make much sense In fact when a limit on the available bit rate is given by the digital hardware the best strategy is to trade precision for bandwidth and the most sensitive receiver is the one with s
76. ly a few posts needed an extension of a few feet The posts varied from 5 to 10 ft depth with compression load ratings of 13 000 to 20 000 Ib TMP Alaska used two hydraulic motor heads one for initial driving of the ten posts and a second with a different gearing arrangement and more torque that turned slower for the final driving Changing the motor reguired only a few minutes Upon completion of the post driving operation the posts were marked with a laser level and cut with a portable band saw TMP Alaska s trailer included a self powered arc welder and the final operation consisted of welding U brackets to the top of each post for the beams figure 7 The complete job reguired a total of 6 h from the time TMP Alaska arrived at Cohoe to their departure 59 Figure 5 The self powered post driver called R2D was brought to the site in an enclosed trailer hauled behind TMP Alaska s pickup truck The machine has local and wireless controls and uses a diesel engine with hydraulic pump An 8 ft post with helix at the bottom can be seen hanging from the geared hydraulic motor ready for installation The posts are galvanized steel and covered with green plastic sleeves The sleeve eliminates frost heaving due to adfreeze of the steel posts and the ground during winter Image 2014 W Reeve 5 Observatory Building The observatory building will house all radio and electronic equipment and living quarters The building uses conventional 2x4 woo
77. ly could not get the LWA TV software image provided by UNM to work on the RPi B was successful only with the RPi B All the information available from the Raspberry Pi Foundation for the model B insists that it is software compatible with the model B but found there were problems that affected the LWA TV GUI These were resolved in September 2014 and the software image now available from UNM works fine on both the B and B Table 1 Comparison of Raspberry Pi Model B and B Hardware Description RPi B RPi B RAM 512 MB 512 MB Memory card SD micro SD Processor system BCM2835 SOC BCM2835 SOC 44 Video 1 connector Standard HDMI Standard HDMI Video 2 connector RCA Composite 3 5 mm audio Composite Audio connector 3 5mm see Video 2 USB connector 2 4 Power connector micro USB micro USB GPIO connector 26 pin 40 pin Network connector 10 100 Ethernet 10 100 Ethernet Power 5V 5 W 5V 3 W Dimensions 85x56x21 mm 85x56x21 mm Mounting 2 holes 4 holes Cost 35 USD 35 USD Hardware The Raspberry Pi can be purchased from any number of suppliers worldwide It is necessary to add a Secure Digital SD to the model B or micro SD memory card to the model B for the LWA TV software image Sometimes the vendor supplies a card with the RPi purchase A card with 8 GB minimum capacity is recommended but 4 GB is sufficient Also an HDMI monitor is needed A VGA monitor may be used if an HDMIto VGA converter figure 4 is connected between RPi
78. mateur Radio Astronomers have teamed up to produce and distribute the SuperSID Sudden lonospheric Disturbance monitor The monitor utilizes a simple pre amp to magnify the VLF radio signals which are then fed into a high definition sound card This design allows the user to monitor and record multiple frequencies simultaneously The unit uses a compact 1 meter loop antenna that can be used indoors or outside This is an ideal project for the radio astronomer that has limited space To request a unit send an e mail to supersid_at_radio astronomy_dot_org SiS TAP OR ECDL ore FADAD RSTRHYMD WWF OG 73 Education Links Space Weather Prediction Center Announces New Website On Tuesday October 14th NOAA s Space Weather Prediction Center will transition its new website into operational status From this date forward www spaceweather gov and www swpc noaa gov will link to the new website that is currently in final beta release at origin www swpc noaa gov SWPC s legacy website will be available to all users for a transition period of at least 60 days The legacy website will be located at legacy www swpc noaa gov Please note that if you have bookmarks or automatic links to pages on the old website these links will no longer work Most of the content will be available on the new site under new links and we will work with customers who bring up specific content issues to ensure that their links are re established on the new site Sin
79. nc is a membership supported non profit 501 c 3 educational and scientific corporation Copyright 2014 by the Society of Amateur Radio Astronomers Inc All rights reserved On the Cover Outgoing President and Vice President Bill Lord 1 and Tom Crowley r with Keynote Speaker Nobel Laureate Dr Joe Taylor at 2014 Green Bank Conference Radio Waves President s Page 3 Editor s Notes 4 News Mark Your Calendar 5 2015 SARA Western Regional Conference 7 RASDR2 Update 8 Feature Articles SIDI the Simple Digital Interferometer Marko Cebokli 9 How to Verify the SNR of a Receiver Based on the AD8307 Logarithmic Detector Christian Monstein 19 Using AAVSO VLF SID Events data the Climax Neutron Monitor records and AAVSO sunspot group counts to look into the anti correlation of the sunspot cycles and cosmic ray flux Rodney Howe 22 Cheap and Simple Demonstration Radio Interferometer Kenneth Kornstett 28 Phase Stability Loss Stability and Shielding Effectiveness Paul Pino 37 LWA TV on the Raspberry Pi Whitham D Reeve 42 Cohoe Radio Observatory Alaska Part 5 Observatory Infrastructure and Building Whitham D Reeve 56 Book Review Title Unseen Cosmos the universe in radio 64 Space Place partner s article Twinkle twinkle variable star 66 Membership New Members 68 SARA Membership Dues and Promotions 68 Administrative Officers directors and additional SARA contacts 71 Resources Great Projects to Get St
80. nchrotron Radiation Graham Smith writes about Hannes Alfen s discovery of the connection between laboratory synchrotron radiation and cosmic radio waves This helped to solve the mystery of the origin of Karl Jansky s discovery of radiation from the Milky Way The book does not list references at the end of chapters or end of book Instead there are eight pages of notes at the end of book that often include references to original scientific journals Unfortunately scientific journals usually are not accessible to ordinary readers and probably would not be of any use to them anyway It would have been nice if the author had provided a recommended reading list for readers wanting a little more depth without the opaque math and physics of a scientific journal paper For readers wanting to expand their radio astronomy knowledge this book is definitely worth adding to your collection 65 Space Place partner s article Twinkle twinkle variable star September 2014 By Dr Ethan Siegel As bright and steady as they appear the stars in our sky won t shine forever The steady brilliance of these sources of light is powered by a tumultuous interior where nuclear processes fuse light elements and isotopes into heavier ones Because the heavier nuclei up to iron Fe have a greater binding energies per nucleon each reaction results in a slight reduction of the star s mass converting it into energy via Einstein s famous equation relating changes in
81. o that used by electric utilities and carries the necessary UL listing for my application installed a metal junction box at an existing cabin and rerouted the existing electric distribution line in flexible conduit to it tapped the new electric line into the existing at this location At the observatory end the electric line was installed in a flexible conduit to a load center which installed inside The new observatory building has no metallic paths to other grounding systems at the Cohoe site so National Electrical Code allows the grounded circuit conductor neutral in the feeder and the electrical equipment to be bonded to a local earth grounding electrode system Using a 10 lb sledge hammer the arm strong method drove an 8 ft x 5 8 in ground rod outside and below the load center In addition to the load center bonded this rod to the tower ground rod about 10 ft away at the tower base The observatory electrical system will include circuits for lighting convenience receptacles radio equipment water heater and ventilation 58 The septic system consists of a 2 chamber septic tank and associated drain or leach field Two 4 in sewage lines were laid in separate trenches from a Y connection one to the new observatory building and the other to the cabin where the water and electric lines are tapped figure 4 The septic system includes clean outs vents inspection ports and other features required by State of Alaska regulations
82. oblem 34 Obviously using two different frequencies and down converting only one of the frequencies was a mistake mistake 7 In my defense it seemed logical at the time and only wanted to obtain fringes However was surprised at the small declination error when 10 GHz was used in the calculation A final thought is that Bruce Randall in a SARA Journal article 8 listed several reasons why the interferometer in his article should not work Therefore cheap and simple stupid often works well as suggested at the beginning of this article In summary a cheap and simple demonstration interferometer was briefly described fringe data from the interferometer was compared to simulation data a declination calculation was performed and final comments presented Not only did the simple and cheap interferometer detect fringes but a reasonable declination calculation was made In addition the goals of both cheap and simple were obtained In the process the design decisions assumptions and mistakes were documented hope this article encourages other people to build an interferometer think it is better to build a system rather than wait and build a perfect system suspect perfect systems often do not get built References 1 Marcus Leech in the SARA Google group on 9 13 08 2 http thehuwaldtfamily org jtrl other Basic 20Primer 200n 20Setting 20Up 20an 20Amateur 20Radi o9620Telescope 9620Bates pdf
83. ocessor chip 50 Enclosure Many different types of enclosures are available for the model B and B RPi but the enclosures for one model do not fit the other Most enclosures are plastic and provide no shielding whatsoever This might be of concern where the RPi is used near a radio telescope antenna or receiver An expensive aluminum enclosure is available for the model B and it should provide better shielding Radio frequency interference took some measurements with a spectrum analyzer and a shielded magnetic loop probe and electric field probe and found several spectral spikes in the high MF and low HF ranges about 1 5 to 8 MHz or so These were apparent only when the probes were held against the clear plastic enclosure of the model B check up to several hundred MHz but found no other indications did not make any measurements with the aluminum enclosure on the model B It should be noted that conducted interference in connecting cables often is radiated because the cables act like antennas so each installation will have different RFI characteristics and it may be necessary to install ferrite beads on all connecting cables Video monitor The RPi uses a standard HDMi connector for video It may be used with a monitor or TV with an HDMI input It also may be used with a VGA monitor by using an HDMI to VGA converter or with a DVI monitor or TV with an HDMI to DVI converter experimented with the HDMI and VGA interfaces on monitors and
84. ower left public domain image of Orion the Pleiades and Mira near maximum brightness by Brocken Inaglory of Wikimedia Commons under CC BY SA 3 0 lower right 67 Membership New Members Please welcome our new or returning SARA members who have joined since the last journal If your name is missing or misspelled please send an email to treasurer radio astronomy org We will make sure it appears correctly in the next Journal issue As of October 14 2014 Gary Evans Sebastopol CA USA N6PAW Michael Hollock Hampton VA USA Anthony Kroes Pulaski WI USA Jack Lobingier Houston TX USA J Lee Varvaro Gillette WY USA SARA Membership Dues and Promotions Membership dues are 20 00 US per year and all dues expire in June Student memberships are 5 00 US per year Members joining from June to December of 2014 will renew their membership June 2015 Members joining January to June 2015 will renew June 2016 Or pay once and never worry about missing your dues again with the SARA Life Membership SARA Life Memberships are now offered for a one time payment of twenty times the basic annual membership fee currently 400 US Journal Archives amp Other CDs Promotion The entire set of The Journal of The Society of Amateur Radio Astronomers is available on CD It goes from the beginning of 1981 to the end of 2013 over 5000 pages of SARA history Or you can choose one of the following CD s or DVD Prices are US dollars and include postage j SA
85. pect to theory Equations 4 through 6 can be easily combined into one equation and applied to any observation 20 Further information and reading Kraus 1986 John D Kraus Radio Astronomy 2nd Ed Powell OH Cygnus Quasar Books 1986 More information about the instrument Callisto and the network e Callisto can be found here http e callisto or Meet the author Christian Monstein is a native of Switzerland and lives in Freienbach He obtained Electronics Engineer B S degree at Konstanz University Germany Christian is a SARA member since 1987 and is licensed as amateur radio operator HB9SCT He has experience designing test systems in the telecommunications industry and is proficient in several programming languages including C and C He presently works at ETH Zurich on the design of digital radio spectrometers frequency agile and FFT and is responsible for the hardware and software associated with the e CALLISTO Project He also has participated in the European Space Agency space telescope Herschel HIFI European Southern Observatory project MUSE for VLT in Chile and NANTEN2 delivery of the radio spectrometer for the Submillimeter Observatory at Pampa la Bola Chile Currently he is guite involved to prepare the radio telescopes for cosmological test observations He plays also the role of a coordinator of Seti League in Switzerland and he is representing Switzerland within Commission for Radio Astronomy Freguencies CRAF Ema
86. phing the simulation plots I used the wavelength for 10 GHz because Figure 8 showed that 10 GHz came closer to being near the two fringe peaks Second I had incorrectly measured the interferometer baseline I had measured from antenna center to antenna center I realized that error while reading G W Swenson Jr s interferometer construction articles 7 If I had thought about it I should have realized that the baseline measurement went to opposite edges of the antennas because the way I measured it a half of an antenna was on each side So another mistake was in not measuring the real baseline mistake H5 With the wavelength and the correct baseline I measured the time between the A and B peaks measured fringe time The equatorial time calculation is the wavelength divided by the baseline The result multiplied by 57 3 converts radians to degrees Multiplying the degrees by 4 converts degrees to minutes on the eguator The arccosine of the eguatorial time divided by the measured time is the declination angle of the radio source producing the fringes The sun s declination on 10 June 2010 was 23 024 degrees from the internet and the calculated declination for 10 GHz was 22 17 degrees error of 3 796 4 Final comments Unfortunately only one run was made for this configuration increased the interferometer baseline the next day and accidently connected the power inserter battery backwards mistake 6 I have since corrected that pr
87. power decreases which is bad Next the two antenna signals needed to be summed together used a DC pass signal summer so that the power inserter would pass voltage through the summer to the inline amplifiers and the LNBF circuit The summer used Channel Vision HS 4 has a frequency range from 5 MHz to 1 GHz This reduced the LNBF output even more The satellite finder operates as a band pass filter amplifier and detector The bandwidth of the satellite finder was 1100 MHz 950 2050 MHz The system bandwidth was 50 MHz 950 to 1000 MHz because of the summer upper frequency limit The satellite finder has a 25 to 75 dBm input level Since the original Ku band radio telescope had worked with the dish before but without the summer the RF link budget was essentially still good especially since was looking at a stronger RF source The receiver link budget considers the signal source system gains and losses in decibels To work the system has to have more gain than the signal source The satellite finder has an audio tone which I had already disconnected too noisy and distracting The satellite finder analog meter was used to input to the digitizer The power inserter supplied voltage for the satellite finder LNBF and inline amplifiers It was just a bias tee with the voltage supplied with a battery A picture of the cheap and simple interferometer antennas is shown in Figure 2 Notice the two inline amplifiers between the Ya
88. rd pan sand and gravel mixture while the contractor s helper looks on Image 2014 W Reeve a Figure 2 Left After dumping a load of sand and gravel backfill the dump truck is loaded with the roots and top soils to be disposed of Right A small tracked front end loader spreads compacts and levels the backfill in the driveway Images 2014 W Reeve 57 Figure 3 The completed driveway is 100 ft long and 10 ft wide The tower can be seen in the back at the right Image 2014 W Reeve 3 Utilities A water well recreational septic system and electrical distribution were built in 2011 for one of the existing cabins and a camping trailer on the Cohoe site The well is to be reused but built a new larger septic system to serve the new observatory and existing and future cabins A new 1 in diameter HDPE water line and 2 AWG aluminum underground residential distribution URD electric cable were trench laid on one side of the new driveway from the new building location to an existing cabin where the new lines are to be connected to existing A joint trench for these lines was dug by the excavator with a narrow bucket after the driveway was completed This method kept the structural soils from being mixed with the unusable top soils The URD cable consists of three triplex conductors each with an extremely tough cross linked polyethylene XLPE insulation designed for direct buried applications The cable is identical t
89. s the test assembly s loss repeatability Changes in loss from the initial coiled state vary no greater than 0 030 dB from 0 066 GHz through 18 GHz The practical example provided for phase repeatability can be applied to loss repeatability as well one may expect a change in loss of approximately 0 010 dB at 10 Shielding Effectiveness 50 ft Assembly Shielding Effectiveness Shielding Effectiveness S E was the only area where a standardized test procedure was used see Diagram 2 for details Referring to Figure 5 the S E performance of the test assembly is recorded for several different configurations In all configurations the S E values of test assembly were consistently at or approaching those of the chamber noise floor Shiehding Effectiveness UB 10 12 14 Th 18 Frequency GHz Performance through 18 GHz was notable producing in excess of 100 dB of shielding effectiveness Figure 6 was provided to demonstrate that data supplied in Figure 5 was merely nota measurement of the chamber ambient noise level Figure 6 displays the contrast in S E Figure 6 Contrasting shielding effectiveness of cable assembly with connector torqued and loosened turn behavior when one connector at the test assembly test lead interface is properly torqued versus loosened by one quarter of a turn University of De die in 2000 after a long career in the automotive industry He joined W L Gore amp Associates In
90. s vary widely and it is best to read your router user manual or search for online help The RPi host name is Iwatvgui without quotes and will be identified as such in your router s local network status screen An alternate and perhaps guicker method is to download and install on a Windows PC a network scan program as described at RPiNet For PuTTY place the RPi IP address into the Host Name or IP address field and click Open figure 9 After authentication you will see the RPi login prompt The default username is pi without quotes After you enter the username RPi will ask for the password For obvious reasons will not publish the password here but it can be obtained by emailing the address given at the very bottom of LWA EPO Updates To update the LWA TV software and archived movie cache send the following commands one at a time using the SSH terminal described above Wait for each process to complete before entering the next command It is necessary to send these commands only upon first use of the LWA TV GUI image cd LWATV syn update updateMovies py v Sudo rpi update Sudo reboot It is a good idea to routinely update the Raspbian software distribution as well Send the following commands with an SSH terminal to update the non LWA TV software these updates and upgrades can require tens of minutes if new distributions have become available after the last update sudo apt get update sudo apt get upgrade
91. sting was conducted using the following equipment Vector Network Analyzer Agilent Technologies 8510C with 8517B S parameter test set Calibration Kit Agilent Technologies 85052B 3 5 mm kit with Agilent Technologies 911E and Agilent Technologies 911D sliding loads 3 26 5 GHz frequency range Vector Network Analyzer Cables utilized on port 2 of the network analyzer Spectrum Analyzer Agilent Technologies 70000 series 37 Mode Stirred Chamber Custom built by Global Partners in Shielding Inc Chamber dimensions 8 feet x 8 feet x 8 feet Note all tests were performed at ambient temperature approximately 20 degrees Celsius and pressure sea level WNA Assembly 3 Return Coil Test Configuration PHASE AND LOSS STABILITY TESTING Stability testing was conducted using the following procedure as seen in Diagram 1 left A full 2 port calibration of the network analyzer was performed using a stepped frequency range of 0 066 GHz to 26 5 GHz 801 points The cable assembly was coiled and uncoiled several times before being tested to simulate normal handling Finally the cable assembly was coiled with loops approximately 1 foot in diameter The coiled cable assembly was connected to the network analyzer 3 5 mm socket to port 1 3 5 mm pin to port 2 and s parameter data was collected This data set was labeled Initial Coil Data The cable assembly was disconnected from port 2 only then uncoiled and l
92. t no hardware construction or software programming is required off the shelf hardware and software is all that is needed Another advantage is that the software for the LWA TV graphical user interface GUI is pre packaged by UNM and available for free When started working on this project August 2014 UNM s software worked only with the Raspberry model B 42 contacted Jayce Dowell at UNM and he updated the software to run on both the model B and B the B is the latest Raspberry Pi hardware version Although the LWA TV software is plug and play there is room for some customization which describe in section 5 started writing this article to answer most of the questions that might arise while setting up the LWA TV application and ended up writing a reference manual The first half provides general descriptive information and the second half contains setup details 2 Long Wavelength Array The LWA is used to study celestial objects or areas of the radio sky in the Note Internet links in braces frequency range 10 to 90 MHz Its primary purpose is scientific but and references in brackets education and public outreach are important parts of its government funded are provided in section 6 mission One of the features of the LWA website is LWA TV a near real time visual representation of the data produced by the array figure 2 2014 08 30 04 39 21 UTC 37 80 MHz V 5 hr m Lf i 7 F i
93. ted with the Welch and Pearson s statistical tests The AAVSO group and VLF SID data show a positive slope and correlation however both data sets show some anti correlation with the cosmic ray counts from the Climax Neutron Monitor data with the strongest anti correlation between groups active regions an cosmic ray flux So it seems that from these statistical tests there is a tighter anti correlation between the AAVSO group counts of solar active regions than with the flaring activity recorded from the AAVSO SID Events data References General reading on cosmic ray cycles http www nmdb eu sites default files NMDB Brochure 1 pdf 1998 H Mavromichalaki et al Simulated effects at neutron monitor energies evidence for a 22 year cosmic ray variation http ruby fgcu edu courses twimberley EnviroPol EnviroPhilo Simulated pdf 2013 Marius S Potgieter Solar Modulation of Cosmic Rays http arxiv org pdf 1306 4421 pdf AAVSO Solar SID Databases http www aavso org sid database 26 R statistical package http www r project org And help from Dr Jamie Riggs www spannedsolutions com These AAVSO data come from our most consistent AAVSO solar sunspot observers from all over the globe who contribute monthly sunspot counts data and SID Events data from VLF observer s submissions all over the globe have a Masters Degree in Remote Sensing Geographical Information Systems GIS Colorado State University 1997 my occupational
94. televisions but did not attempt to use DVI For portable use say at a convention a small screen monitor would be handy Many compatible types are available for example search monitor at Adafruit to see a variety of 5 6 7 and 10 1 in monitors with HDMI inputs have not tried any monitors TVs except those discussed below initially connected the RPi to the HDMI port on a Hannspree HF 199 monitor The HF 199 has HDMI and VGA input connectors and its maximum resolution is WXGA 1440x900 pixels 16 10 aspect ratio found that the displayed image was slightly elongated horizontally when using the LWA TV GUI default settings To change the video settings it is necessary to edit the config txt file in the boot folder of the RPi It is best to do a little research on the internet before making any changes Use nano to edit the file nano is a simple text editor built into the software image sudo nano boot config txt After making the desired changes and saving the file reboot the RPi sudo reboot I tried changing the RPi video settings to different screen resolutions and eventually found that only one HDMI mode provided a better display and that was at the monitor s maximum resolution 1440x900 hdmi_ group 2 hdmi_mode 47 However at this high resolution the real time display and archive movies sometimes would momentarily stall or skip then tried an HDMI to VGA converter on the monitor s VGA input and could not obtain a
95. terferometer that can think of Simplicity this refers mainly to the hardware It was to be kept as simple as possible mainly by putting as much processing as possible into the software Keeping the hardware simple also makes it cheaper and accessible for self construction by those who like the smell of the soldering iron High performance it should at least match the performance of the best existing amateur analog interferometers like those by Hans Michlmayr 2 or IRO Indian River Observatory 3 VLBI capability this is the long term goal as set by ALLBIN The plan with SIDI is to see how far the fancy phase locking hardware and disciplined clocks could be replaced with software in post processing 2 Basic design choices 2 1 Choice of operating frequency Most celestial sources are stronger on lower frequencies and VLBI synchronization also gets simpler as one goes lower in frequency But on the other hand the density and levels of undesired interference also increase rapidly with decreasing frequency and the available bandwidth gets smaller decided to choose the well known 21 cm band for several reasons Devices like filters LNAs low noise amplifier feedhorns etc are widely available from several sources Cheap satellite TV coax cable has low enough loss for baselines up to 50 m Cheap satellite TV line amplifiers are available There are enough bright sources in the sky for example the VLA 1 4 GHz survey 4
96. the Raspberry Pi model B or B The cost is 15 USD including postage to any US destination and most other countries About the Author Whitham Reeve has been a director of SARA and presently is a contributing editor for the SARA journal Radio Astronomy He worked as an engineer and engineering firm owner operator in the airline and telecommunications industries for more than 40 years and currently manufactures solar radio spectrometers and accessories 55 Cohoe Radio Observatory Alaska Part 5 Observatory Infrastructure and Building Whitham D Reeve 1 Introduction This article series describes construction of a new radio observatory in Cohoe Alaska The current part Part 5 describes the construction work undertaken during summer 2014 The previous four parts in this series are it Part 1 Radio Frequency Interference Survey Reeve1 Note References in brackets Part 2 Guyed Tower Foundation Construction Reeve2 a lprovidedintseetion 7 fr tx Part 3 Guyed Tower Installation Reeve3 it Part 4 Callisto Antenna System Reeve4 The latest work consisted of construction of a driveway and the installation of water sewer and electric lines building foundation and the building itself The building exterior is finished but the interior is not The activities are individually described in the following sections My original plan was to have this entire project completed by end of summer but demands for radio equipment that manuf
97. to abandon the commecton vee mo ca Figure 9 Upper left Screenshot of PUTTY configuration window with the IP address for one of my setups Upper right Upon first connection PuTTY asks for authentication Lower left When PuTTY is connected the window changes to a simple command line interface After login you can make changes to the RPi Images 2014 W Reeve Documentation Online documentation for the Raspberry Pi including troubleshooting information is available at RPiDoc and RPiHub There also are numerous forums that have information related to RPi The only documentation that exists for the LWA TV application is this article and information at LWA EPO Keyboard mouse The LWA TV GUI has built in drivers for a USB keyboard and mouse but they are not required for normal operation However a keyboard is nice to have if you need to directly access the RPi or cannot access it indirectly using SSH as described above Small wired or wireless keyboards with or without a mouse figure 10 are available from Adafruit Figure 10 Wireless keyboard and mouse uses a Bluetooth connection The keyboard is about 285 mm long A Bluetooth dongle is included and requires one USB port as seen on the left of the RPi model B in the image Image 2014 W Reeve Heat The RPi processor normally runs warm but not hot While using LWA TV measured about 30 C using an infrared non contact thermometer pointed at the pr
98. tor and a simple parallel port based I2C interface gave a nice compact unit 11 fig 3 Sampling was still done with a software loop on a DOS machine and the filters were chosen for a 400 kHz bandwidth At Pavle s location we tried for some fringes from the Moon but got an unknown satellite signal in the first try This gave me the idea to play a little with the GPS signals 12 since these were planned to be used as a reference in the future This led to the next experiment Figu re 3 which was to make an image of the GPS birds in the sky Using two small active GPS antennas and moving one manually through the 256 positions in a regular 16x16 grid drawn on the tarmac in front of the house 13 we succeeded in getting some images fig 4 presented SIDI 1 1 at the 2006 ERAC congress in Germany 14 and it won a special double decker version of the ERAC s FFT DSP award fig 5 At least two other people have successfully built their versions of SIDI 1 1 15 16 The conclusion after experimenting with SIDI v1 1 was that sat TV tuners are well suitable for interferometry They have a few weak points like poor selectivity and a relatively high noise figure The noise figure worsens rapidly when their gain is reduced via the AGC automatic gain control pin To get the NF below 10 dB they have to be run at maximum gain making them very prone to overloading by off freguency signals Kimmo Siditiri2 gt Lehtinen above
99. uties of these positions at http www radio astronomy org pdf operating procedures pdf The editorial staff of the Journal is working very hard to publish a guality publication for our members They welcome articles about observations member projects designing eguipment software used for observing book reviews and analyzing data Please think about taking some time to write and tell us about what you are doing This will enhance the Journal for all of our readers This will be the first issue of the SARA Journal with Kathy Hagen as the editor She has big shoes to fill as Melinda steps down as the editor May your noise figure be low Ken Redcap KR5ARA Editor s Notes We are always looking for basic radio astronomy articles radio astronomy tutorials theoretical articles application and construction articles news pertinent to radio astronomy profiles and interviews with amateur and professional radio astronomers book reviews puzzles including word challenges riddles and crossword puzzles anecdotes expository on bad astronomy articles on radio astronomy observations suggestions for reprint of articles from past journals book reviews and other publications and announcements of radio astronomy star parties meetings and outreach activities If you would like to write an article for Radio Astronomy please follow the Author s Guide on the SARA web site http www radio astronomy org publicat RA JSARA_Author s_ Guide
100. uts After using the TV menu to select the HDMI port the screen immediately showed the correct display made no changes in the RPi video settings 720p used with the 47 in TV previously described Date time and time zone By default the Raspbian distribution uses Network Time Protocol NTP to automatically set the RPi time when it is connected to the internet The RPi does not have a real time clock or battery backup so it must be running and connected to the internet to correctly set time and date To confirm the date time and time zone enter the following at the RPi prompt on the SSH terminal date To change the time zone enter the following The displayed instructions will lead you through the reconfiguration sudo dpkg reconfigure tzdata To confirm the scheduled download time for the daily LWA TV movie archive update enter the following to see what is in the cron table cron is a utility that runs automatically in the background at specified times crontab l You should see a number of comments with the last two lines as follows m h dom mon dow command 30 18 python pi LWAIV updateMovies py The last line is the scheduled event with a time of 1830 in the system time zone It is shown in crontab with minutes before the hour To change the scheduled time enter the following to edit the cron table This will 52 invoke the default editor and allow you to change the time in the table Do not change anything on the
101. vso In taking a look back through these AAVSO solar data with the American relative index data it is possible to de convolve the raw Wolf numbers W 10g s into group g and sunspot s counts Once we have the group counts data we can compare those with both the SID freguency counts and the Climax Neutron Monitor flux counts Averages Output 140 Counts 20 40 60 50 100 0 0 1000 2000 3000 4000 5000 6000 aavso_VLF red aavso_g green Cosmic Ray blue Figure 1 shows the group counts in green bottom line the VLF freguency counts in red and the Climax Neutron Monitor flux counts flux 60 in blue These data cover 4 solar cycles from 1966 thru 2006 when the collection of Cosmic Rays from Climax were shut down The X axis is in days It s easy to see that when the group and SID event data reach their maximum that the cosmic ray flux approaches its minimum This is what is meant by the anti correlation The guestion though is does the cosmic ray counts data anti correlate more closely with the AAVSO group counts data or with the AAVSO SID Events data These data streams are stacked as in Figure 2 to show visually how each compare to the other Note the Y axis is different for each data stream 22 Averages Output jdt 450000 250 40 80 m00 cosmic ray aavso_g aavso VLF 15 45 55 65 750 5 0 1000 2000 3000 4000 5000 6000 Time Figure 2 shows how the anti correlation is not guite so obvious Which h
102. ww 7 zip org http www 7 zip or Adafruit http www adafruit com http www adafruit com LWA LWA TV LWASoft http fornax phys unm edu lwa trac downloads http fornax phys unm edu lwa trac downloads L Notepad http notepad plus plus org http notepad plus plus or PuTTY http www putty org http www putty or RPi http www raspberrypi org http www raspberrypi or RPiDoc http www raspberrypi org documentation http www raspberrypi org documentation RPiHub http elinux org RPi Hubhttp elinux org RPi Hub RPiNet http www cpdforteachers com resources finding the ip address of your raspberry RPilP RPiWi Fi raspberry pi via the command line SDFmt https www sdcard org downloads formatter_4 https www sdcard org downloads formatter 4 TeraTerm http ttssh2 sourceforge jp index html enhttp ttssh2 sourceforge jp index html en WDimg http sourceforge net projects win32diskimager http sourceforge net projects win32diskimage r Acknowledgement Jayce Dowell at UNM helped me immensely with this project and I hereby extend my thanks and appreciation The ratio of Jayce s knowledge of the Raspberry Pi and LWA to my knowledge is very close to infinity zero Contact Information for Preprogrammed Memory Card 54 Orderlnfoj reeve com A preprogrammed micro SD memory card may be ordered by emailing The micro SD card includes an SD carrier and will work in either
103. xploring the invisible radio universe today Check out the new Radio Astronomy Observing Program online at http www astroleague org programs radio astronomyhttp www astroleague org programs radio astronomy observing programobserving program 72 JE amp fPlanetary Radio A Astronomy for IIN The Radio Jove Project monitors the storms of Jupiter solar activity and the galactic background The radio telescope can be purchased as a kit or you can order it assembled They have a terrific user group you can join http radiojove gsfc nasa gov The INSPIRE programuses build it yourself radio telescope kits to measure and record VLF emissions such as tweeks whistlers sferics and chorus along with man made emissions This is a very portable unit that can be easily transported to remote sites for observations http theinspireproject org default asp contentID 27 Sky Scan Awareness Project When a meteor passes through the Earth s atmosphere it ionizes the atmosphere which improves its ability to reflect radio waves This allows you to briefly hear a far away radio station that you normally couldn t detect In this project you can install an antenna use an FM radio receiver computer software and learn to observe meteor showers using this very simple radio telescope For more information about this project please visit http www skyscan ca getting started htm SARA Stanford SuperSID Stanford Solar Center and the Society of A
104. your internet router and 3 micro USB connection to an ac power adapter When power is applied the RPi system automatically starts and the display will show lines of text that scroll by rather guickly Upon completion of the boot up process the display will momentarily blank and then the LWA TV GUI will appear The LWA TV GUI shows the real time images plus archived movies figure 7 If the program is running but does not have a proper network connection you will see Error Downloading Image and Network Connection Error on the display figure 8 An archived movie may be running but the live portion of the display will be gray The LWA TV GUI connects within a second or two after the network connection is established I did not have to make any changes in my internet router for LWA TV but if you have network connection problems your router and its firewall are the first place to start troubleshooting after checking that the cable is plugged in If everything seems to be working okay it is a good idea to update both the software and the archived movies upon first use Log into the RPi console as discussed in the RPi console part of section 5 and execute the commands given in the Update part 46 wo 5 Monitor m Hayk WN eneth Ty Raspberry Pi Mu Sr patti i ip in i odet ree cease Mode 6 or E 7 Se Station 1 New Mexiunu KY ras Pr LL Re s Mmm y Bee a Z EN YY Cel na y nni bara wr TY HAN colle
105. zer converts the detected analog signal to digital data which is stored ona laptop computer file The voltage for various blocks is supplied by the power inserter More detail will be presented later but let us look at some system requirements The first design decision was the operating frequency Since had already made several intensity radio telescopes Ku band 2 4 GHz quad on a dish and 1 4 GHz helical it seemed obvious cheaper to migrate one of those systems to an interferometer system The Ku band radio telescope seemed a possibility design decision 1 It accepted frequencies from 12 2 to 12 7 GHz Ku band and down converted to 950 to 2150 GHz 1200 GHz bandwidth The Ku band system included a dish a Low Noise Block Down converter Feed horn LNBF a satellite finder a homemade digitizer and power inserter to supply power to the LNBF and satellite finder decided to use the LNBF without the dish for three reasons First had only one Ku TV satellite dish and LNBF and did not want to scrounge up another one or worse yet buy one The second reason was that thought it would be difficult to aim the two dishes I have since realized that is not a problem one uses small mirrors to focus the sun s reflection on the proper feed horn of the LNBF for each dish The final reason was that without the dish the LNBF would have a large beam width The dish has a narrow beam width while the LNBF probably has greater than 45 degrees

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