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RAGazine - British Astronomical Association

1. 4 British T stronomical Asso tranamy Gral stro org radio The X RAGazine The quarterly newsletter of the British Astronomical Association Radio Astronomy Group BAA RAG BAA Burlington House Picadilly London WIJ ODU 44 207 734 4145 Reg charity 210769 co ordinator Hyde RAGazine editor Dave James The RAGazine is published in primarily electronic form for download in low and high resolution pdf formats For a free subscription to The RAGazine send an e mail request with RAGazine subscribe in the header to the editor at dave greenover net Publication is around the first day of Sep Dec Mar and June Subscribers receive an e mail alert containing the download links when each new issue is available A small number of paper copies may be made available on request We solicit items of news articles on construction and observing projects on outreach and educational areas book reviews historical descriptions anecdotes etc which are of potential interest to amateurs in radio astronomy and geophysics We also encourage inclusion of relevant individual and commercial adverts for sale and wanted and volunteer appeals all at no charge The deadline for contributions is 3 weeks before the publication date To contact the editor dave greenover net 01769 561 002 Most common file and picture formats are acceptable where possible please contact
2. Left The Group has two display stands for poster presentations and material covering Sudden lonospheric Disturbances magnetometry solar radio bursts hydrogen line reception and a selection of amateur radio astronomy antennas Below Paul Hyde presenting the first talk of the day on a beginners guide to amateur radio astronomy In addition to the practical demonstrations the RAG team provided two short lectures on radio astronomy The Beginner s talk was very well attended despite being the first lecture of the day and the opening minutes were taken up with a frantic doubling of the number of seats available The Advanced talk proved less popular either due to exhaustion on the part of the audience or perhaps an intimidating title Nevertheless feedback on both talks was very positive The RAG team John Cook Paul Hyde Andrew Lutley lan Williams was supported by Neil Breckell of Farnham Astronomy Society demonstrating and talking about Jupiter reception and Bob Kerswill of Basingstoke Amateur Radio Club covering VLF reception and meteor scatter We were all encouraged by the interest shown by visitors and there were several lengthy discussions on observing targets and techniques The TNMOC team headed up by Sheridan Williams were excellent hosts providing the support for _ setting up the demonstrations presentations plus providing a continual supply of tea and coffee An excellent day all round
3. Fr MERC cA s be Left ATC channels as seen SDR Sharp a we v Once you have verified that the un iss receiver and antenna are Gua working and SDR is displaying SIGNALS you can search for meteor pings The following SDR settings are recommended Radio Demodulation Frequency Centre Frequency USB upper sideband 143 049 000 Hertz 143 047 000 Hertz should be OFF unchecked and FFT Resolution 32768 32k or 65536 64k Other settings should remain at their default values or as recommended in the FCD User Manual e g the Correct IQ and Swap amp Q boxes should remain checked You now need to wait for a meteor reflection Activity generally peaks in the early morning hours but there should be sporadic events throughout the day During meteor showers you may see an event every minute or so even during the afternoon and evening periods ee ee hasi ele Left Meteor trail event as seen using SDR Sharp 1 See www radios uk com airfrequencies htm RAGazine Sep 13 Detailed monitoring work or similar SDR applications are good for proving out the system and for using the FCD for receiving signals other than meteor scatter However for detailed work you need Wolf Buscher s Spectrum Lab This is a freeware spectrum analyser application which has been developed over many years to support various inv
4. C i jm 1 i CoU c ment d Above Two happy collaborators after successful observation of solar emissions at 12 GHz RAGazine Sep 13 Amateur Radio Astronomy Group tracks Milky Way Hydrogen emission New RA project team A group coordinated by Gordon Dennis is starting a new project to make precision low noise observations of hydrogen emissions from the Milky Way Commencing in the autumn of 2013 the project will use Brian Coleman s 3 7m parabolic dish telescope located near Andover The dish itself was originally used for the development of satellite television with the feed system low noise amplifier LNA receiver and tracking system designed and built by Brian himself Recent improvements to the H Line feed and LNA arrangements have yielded a system noise temperature of about 56K Amateur astronomers will be able to drive the telescope remotely over the Internet in much the same way that professional astronomers are able to control telescopes at other observatories including the University of Manchester s Jodrell Bank Amongst other things this will enable those without radio experience to be able to map structures in the Milky Way Gordon has been set the task of bringing together a small team of amateurs to identify observing objectives and help develop analysis techniques The aim is to do serious precision science managed along professional lines Volun
5. We did some rough and ready measurements and estimated the forward gain in free space to be 9dB referenced to a dipole The response at 90 degrees that is off the edge of the tin open end lip was approximately 20dB referenced to the main lobe To the left are the two preamplifiers 3 we used for the experiments The first larger enclosure has a measured noise figure of 0 45dB at 1420MHz and 32 5dB gain The second one on the right has a 0 95dB noise figure and also 32 5dB gain Each is powered using a bias tee feed at the receiver end see below The remaining parts of the system are shown here The cable is approx 10m long with a loss of 8 5dB at 1420MHz The bias tee splitter have a through loss of 4dB The FUNcube Dongle 4 perhaps be familiar RAGazine Sep 13 We measured the FUNcube Dongle Pro noise figure at 5 1dB 1420MHz LNA on and mixer high Even with a sky directed antenna it s best not to use unnecessary gain when optimising the capabilities of your first stage preamplifier The tables here show the gain required from the first stage preamplifier to ensure the specified noise figure is achieved for your down stairs ee ae receiver input oe n o Ting 0 9 Our feed cable plus bias tee n splitter together have a loss of 12 5dB Each preamplifier has a gain of 32 5dB so the net gain at the RX port is 20dB From the upper table we c
6. ETIN NOMEN MER moh JAipparirm F HPT h M i 1 i D 80 48 Lene M b i a T F i I Li Apparent ST As soon as the clock is running the Clocks Tab shows all of the time systems available which all calculated on the fly from the basic timer running in the computer s clock The most useful will probably be UniversalTime UT and LocalMeanSiderealTime LMST If you prefer to see other times then the control panel of the ObservatoryClock may be configured to display any two of these time systems There are several other generic Tabs on the user interface UI but one which is more specific to the clock is the Ephemeris generator Here you can select one of several target objects and given a time step and a location calculate the coordinates of the target as shown below It is straightforward to change the list of ephemeris targets to include a few of your own or to remove those that are unwanted RAGazine Sep 13 Ephemeris of the Moon The above output shows the position of Earth s Moon every 300sec for the Observatory location This output may be exported or printed so a variety of documents may be generated for use during an observation Note that the clock must be running and the Observatory Metadata must contain the Observatory s locati
7. PCB Antenna A range of low cost high quality PCB Log Periodic Yagi antennas covering 400MHz to 11GHz Prices vary from 5 to 20 according to antenna type and whether a connector is supplied Further details including my e mail address are available on my web page www g4ddk com Sam Jewell RAGazine Sep 13 Meeting of the Radio Astronomy Group Oct 27 2012 at the National Space Centre Leicester Diane Swan Some 120 participated in this 2012 meeting on a cold but sunny morning at the National Space Centre in Leicester The NSC s conference suite offered increased capacity this year but even so the event was once again over subscribed The assembly was greeted with an array of demonstrations of equipment from group members including an impressive steerable parabolic dish A number of presentation screens around the room displayed a fascinating mixture of historic photographs and images from previous RAG meetings Paul Hyde Coordinator of RAG introduced Karen Holland as chair person for the day Interferometric detection of an extra galactic radio source In this first presentation Dr David Morgan considered the use of radio interferometers for observing M87 in the constellation of Virgo This elliptical galaxy has an active nucleus which produces an enormous lobe of high energy material emitting broadband synchrotron radiation Targets such as these represent a challenge for the amateur due t
8. This is sufficient for full SNR detection and temperature measurement of galactic hydrogen with moderate angular resolution in both latitude and RAGazine Sep 13 longitude The FFT frequency resolution as described does not require antenna tracking and is sufficient to indicate and separate the galactic arms Increased demand for better angular resolution requires larger dish apertures Better frequency resolution requires longer dwell times and therefore accurate tracking of the antenna pointing direction References 1 http www britastro org radio projects Measurement_of Neutral Hydrogen Velocities pdf 2 http www britastro org radio projects An SDR Radio Telescope pdf 9i http www yagicad com YagiCAD YagiCAD htm 4 http www g4ddk com 5 http www wa4dsy net cgi bin idbpf 6 http www ussc com uarc utah atv interdigital1 html 7 http www funcubedongle com 8 http www moetronix com spectravue htm 9 http www sdrsharp com index php downloads 10 http rtlsdr org softwarewindows 11 http sdr osmocom org trac wiki rtl sdr 12 http inst eecs berkeley edu ee123 fa12 rtl sdr html 13 http www y1pwe co uk RAProgs RadAst htm 14 http www y1pwe co uk RAProgs RAFFT exe 15 http astro u strasbg fr koppen ISGH5 index html 16 Burke BF Graham Smith F An Introduction to Radio Astronomy Second Edition 2002 Appendix Post processing Both OsmoCom rtl tools and the FFT averager are
9. After six years of trying to outwit and defeat German engineering Ryle could now profit from it It is sobering to think how life has changed since those times and how the radio spectrum has filled so greatly was intrigued to notice for example that the picture on the front cover see figure above is that of one of the antennas used by Hey s group and which helped lead to the discovery of the discrete radio star Cygnus A But where was it sited In Richmond Park London If you don t know London well this public park has an area just about the size of the Bois de Boulogne in Paris or some three times that of New York s Central Park oummary For me this is the definitive book to chronicle the early days of radio astronomy in all its facets One can gain some greater insight into radio astronomy and geophysics too unless you are already an astronomy professional This is digestible scholarship of the highest order Beg borrow or steal a copy but not mine Editor s note This review also appears in the Jul Aug 2013 issue of Radio Astronomy J of SARA T T Ste x INN Uu We sent a message to any extraterrestrial beings in deep space was picked up an observatory in Great Britain They didn t understand it RAGazine Sep 13 VLF Quarterly Observing Report to July End 2013 John Cook jacook jacook plus com The VLF flare activity chart Fig 1 below sho
10. makes this a poor receiver choice for hydrogen line work If the software FFT size were reduced to 32 points 3kHz bins RAGazine Sep 13 this would give 8 fold reduction in noise much improving the data quality and receiver sensitivity To get an equivalent improvement by alternatively extending the observation time means an increased dwell time from 100sec to more than 1 75hrs Option B 15 The Realtek RTL2832U DVB TV dongle RTL This is compatible with SDR software and needs the Zadig driver for WINDOWS For Hydrogen line astronomy the SDR spectrum displays are not very useful containing only time constant variable attack and decay on FFT bins There is however the facility to record formatted files of I Q samples at clock rates typically 2 048MHz offering a 2MHz analysis bandwidth suitable for processing off line OsmoCom have produced an rtlsdr library and capture tool The capture tool produces files bin containing raw IQ data for later analysis and can be viewed using programs such as hexdump exe A good description of the rtlsdr tools and data analysis procedure is given in reference 12 As an alternative a Java applet and exe programs have been written to accept OsmoCom captured data to average FFT spectrum results and to output text files that can be further processed and viewed in Excel or MathCad The Java applet is useful for quick assessment of shortened r
11. recover their responses and feed some values into subsequent Commands thus building complex control routines RAGazine Sep 13 Expert User Now is probably a good time to invest in a new pair of open toed sandals and to grow an unreasonable amount of facial hair mentioned earlier that the SimplePlatformClock may or may not be accurately synchronised What happens if you use the computer s clock just as it comes Well unless you are very lucky it will drift The recording below shows how my computer clock drifted relative to time obtained from the network via Network Time Protocol or NTP Clearly after a very short time the clock would become useless for anything other than the simplest observations The amount and rate of drift will depend on many things and if you try this experiment your results may be very different Offset between local clack and network time Leto gt aite T P 32004 eia C T acto Sm 2800 D LEN E ki t 26 s 5 eb e 5 Li Unadjusted clock AS 4730 3L0 1920 1645 18ID 1815 3805 2EDS MM 2045 2120 1145 2030 2046 2215 hr ira drift vs time mz se haliman nca a tins So we need some way of ensuring that the ObservatoryClock presents an accurate time to all observatory instruments but without asking for user intervention if possible Some operating systems
12. 2 3 3 003903 ERO a CCCB CCCC CCC CMC CMXC CCCC CCC CBC 2430 1 2431 2432 2433 2434 2435 2436 2437 2438 2439 2440 2441 5 26 7 28 7 EES 1 _ sina MMMX wem MMMM CCCC MMCC CCCC CCCC MCCC 2442 2443 17 20 gt 2 eee F CMCM MCCM 2444 CCCC CCC CCCC 2012 November 12130 2 21 22 24 o NE 231 2 3 2445 BAA Radio Astronomy Group 2446 2447 2448 2449 2450 2451 2452 2453 2454 2455 BARTEL DIAGRAM CCCC 27 CCC CCCM 10 11 CCCC CCC MCCC CM 10 11 CCC CMCC CCCC 3 4 CC MCCC CCCC 12 13 CCMX 5 CCCC 2013 August 2 12 GHz Amateur Radio Astronomy Experiments Jonathan Rawlinson jonathanpieman gmail com MOZJO Preface My name is Jonathan Rawlinson and am 18 and have just completed my final year of A Levels have been a radio amateur for about four years although am not on the air much live on the border between Kent and East Sussex in the South East am going to do an industry placement this year before starting a physics degree in 2014 Since being trained by the QRZ Amateur Radio Group of Sussex QRZ ARGOS my interests have diverted from operating phone and digital contacts to radio astronomy and reception of other signals weather satellites HF fax etc This interest was spurred on by readin
13. 400 was pointed away FA from the sun so the peaks are only due to Ate temperature Note the 200 different heights of the peaks corresponding to hotter and cooler days Li Es gola Er rb gr n ag yl Eu kb bl a A 5000 10000 15000 20000 25000 30000 35000 40000 Time Index 1 2m dia dsh After this acquired a 1 2m dia dish from eBay which came with a high quality LNB feed horn rotator and two fully functioning satellite boxes quickly ripped apart one of the satellite boxes and utilised the 36V http www princeton edu achaney tmve wiki1OOk docs Feed horn html RAGazine Sep 13 power supply to make a rudimentary manual rotator controller then used an old satellite finder as shown above to get a total power output from the dish The set up 1 very similar to an IBT as mentioned earlier Images of the dish are shown below xU zm E rp ing ate 21 m rA y 1 z The 1 2m dish with Ku LNB The Ku LNB ET generic Konig Satellite Finder is suitable for this any satellite finder that is able to give a voltage response proportional to the signal strength RAGazine Sep 13 This equipment was then connected to an Arduino which in turn was connected to PC using hyper terminal to log the output then scanned across the area of sky containing the sun and graphed the output using Mi
14. Eu Enter a frequency of 143047 kHz and click on the Set Frequency button You should see a confirmatory message the right hand window This setting will place the meteor reflections at around 3 kHz which is rather high pitched for listening to but it does move them away from the higher noise levels found around the centre frequency of the FCD Setting up Spectrum Lab Download and save the latest version of Spectrum Lab at the time of writing this is v2 79 The application will launch at the end of the install process You should be able to see the FCD receiver listed as an input device on the Audio I O screen under the Options tab but there are a number of configuration steps needed before you can use it There are so many different settings available for Spectrum Lab that the recommended approach is to use a proven configuration file available from the author This sets up Spectrum Lab to do the following 1 See www qsl net dl4yhf spectral html 2 See www funcubedongle com Mylmages FCHid2 002 zip or the latest version executable not source RAGazine Sep 13 1 Accept an external stereo sound card which is what the FCD looks like using a sampling frequency of 192 kHz Only one of the stereo audio channels is actually processed Spectrum Lab should now select the FCD as it opens 2 Decimate the incoming samples by a factor of i e throw 7 8ths of them away This restricts the observable spec
15. OS allow users to set up a synchronising process that regularly connects with an NTP server and adjusts the local clock Some OS do not allow such changes to other than users with administrator privileges which can sometimes cause problems Also the method of synchronisation is restricted to that provided by the OS i e NTP or to custom external software The method finally chosen to overcome these restrictions and to allow complete control over the clock steering algorithm is call a Proxy Clock The diagram below attempts to explain now this works The user on the left sees the wall clock time as before and is unaware as to how the time has been generated The users does not know or need to know what goes on behind the wall The helpful but rather controlling character on the right has access to a master clock and every now and again adjusts the time on the user s clock to match that of the master So what the users thinks is a clock is nothing more than a simple indicator driven from somewhere else Ceci n est pas une horloge User views Proxy Clock set by a hidden process RAGazine Sep 13 This abstraction of the function of the clock is common theme in programming It allows the functionality to be changed at will even at runtime without changing the software that uses the service provided So in this case the user keeps calling getTime but the Time may be coming from somewhere else One of the simplest
16. amplifier with lossless negative feedback to ensure an excellent input match minimum noise figure and stable operation Second stage bias is actively stabilised to minimise gain drift VLNA21 features an equivalent noise temperature of below 20K and a gain of over 30dB typically 33dB so that in most circumstances a second stage preamplifier is not required hence saving you additional expense and ensuring a low overall receiver system noise temperature The VLNA21 is available only as a kit However can arrange for your kit to be built for you and professionally aligned to give top performance at 1420MHz for a small additional fee Each assembled VLNA21 is hand crafted and guaranteed for 12 months VLNA21 kits are just 50 each and feature clear comprehensive instructions on construction for this particular band Assembly and alignment costs 40 to make a total of 90 for the pre built and tested unit Delivery is approximately 4 weeks from receipt of order SPF Amplifiers These little amplifiers are offered as low noise high dynamic range VHF and UHF low noise amplifier kits suitable for use between 50MHz and 1GHz 4 3 fra 7965 SPF Amplifiers are only available as easy to assemble aa surface mount component kits The kit consists of the device P PCB and all passive components You supply cable connections and screened box SPF Amp kits are just 12 each
17. astronomy using space and ground based instruments galactic astronomy where UH has the lead in several major surveys from optical through mm wave frequencies continuing development of world class optical and IR polarimeters and spectropolarimeters for UKIRT and AAT also HATPOL TRISPEC SIRIUS The UH has an observatory at nearby Bayfordbury which is used for internal teaching for outreach and some research Very unusual these days It seems unusually well equipped with eight optical telescope domes and a 4 5m dia H line and continuum L band radio telescope The optical telescopes range up to 0 5m dia All these seem robotic and most interestingly the latest addition is to be a three element microwave interferometer 115 max baseline This new arrangement shown at the right was started in 2011 and we understand that it is taking much longer than expected to get operating Despite what it states on the main UH web site it is understood that the three antennas are all 3m and not 4m dia The front end units are understood to come from Univ Uppsala the dishes from the USA The positioners are SPID and the correlation scheme features a thousand core processor Intrigued The normal public outreach visit arrangements do not seem quite appropriate for a visit by a small group of amateur radio astronomers so if you are interested in joining the little Devon Astro amp Geo Group DAGG in a planned vis
18. case for the popular Raspberry Pi that is crafted out of seven unique layers of spruce hardwood with a transparent top and base Available from Pi Hut honest RAGazine Sep 13 Laurence Newell radio telescope btinternet com 4 Introduction 5 Welcome to the first edition of the Starbase Log which aims to keep you up to date with progress of our software observatory project and to gradually describe the features available for use A document is available here http www ukraa com www starbase html which gives some of the background to the project and of the various design philosophies used so won t be repeating that material The idea is to encourage you to experience and experiment with the software in manageable steps in the hope that you would like to join our small but growing band of enthusiastic users or even developers 1 18 10 54 CERS o xw a Obserwator Clock Step One After some deliberation l ve decided to begin by describing the ObservatoryClock Why the Clock Well almost everything you will do with an instrument will require knowledge of the time Normally a software program will obtain Time from the real time clock hardware on the host computer This clock is maintained by a battery and is usually set by the user or perhaps adjusted now and again from the network However the observer will usually need the local time or wall time sidereal time or maybe fixed poin
19. cold sky ratio 3 7dB but unwanted noise we can calculate Tu and Ta as 71 and 18 Atmospheric emission and background noise at this frequency are about 3 each The efficiency of a Yagi antenna should be better than 90 so unwanted ground noise should be less than 29 Lets say it is only 80 efficient then unwanted ground noise rises to 58 which seems to fit the figures A rough calculation of the signal noise Ta follows The antenna beamwidth is 26 so the expected measured signal temperature of a 100 Kelvin hydrogen cloud of angular extent 5 x 30 is 17 which appears about right Similarly for the sun assuming the subtended angle is 0 5deg and equivalent surface temperature 70000deg 6 the expected equivalent temperature with the antenna pointed at the sun is 70000 0 25 26 26 26deg Since the value for Ta is reasonable but Tu is not there is also the possibility that the antenna copper losses may contribute 0 5dB loss would account for 35 There is also possibly some man made noise being intercepted still Signal Integration Temperature Sensitivity The system temperature Tsys from the previous section is Tsys Tu Trx and with integration the temperature resolution is Tsys N nbt 175 68 5 2 5deg for the FUNCube dongle and 175 600 0 3deg for the RTL dongle Considerations Limitations and Improvements Interference Beware of local interference in th
20. d 2 nras Ge nens TIT nim Limes LB T Ti EH mm 2 Ti T Fd Lo I TA em omn mua c Ys an um I Jan dan San j Hemd 5105 2013 065 13 Jahn Wardle T fu E p Cn i T ji lt F a J s d F x 1 i pofi 1 te n 1 vj d g r won This is a Starbase chart showing observations at 5 different frequencies Note in particular the differing SID shapes at the various frequencies The sharp spike at 21 7kHz black contrasts with the double dip response at 19 6kHz dark blue Note also that while some frequencies show SIDs as peaks in signal strength others show a dip This is quite normal and due to the relative phases of the sky and ground wave components at the receiver All of the flares on May 2013 May 27 13 had fairly short rise times of the order of 5 or 10 minutes typical of many solar flares Fig 3 right shows an M5 0 flare on May 2219 that was very slow in comparison The X ray flux measured by GOES is in black and my 23 4kHz SID is in red Note that there are two short drop outs in the GOES data between 14h and 15h The X ray flux can be seen to build up over a period of an hour taking another 5 hours to decay again The SID is drawn out in a simi
21. description of the processes leading to the formation of pulsars Born in the cataclysmic collapse of massive stars these dense objects conserve both angular momentum and magnetic flux as they collapse forming rapidly spinning compact objects with powerful magnetic fields These often lead to beamed radio emission along the magnetic axis and if the path of the beam sweeps past the earth a suitable receiver would detect a pulse of energy Prof Lyne then considered the creation of binary pulsar systems and millisecond pulsars objects rotating so rapidly that the pulse of radiation from the star occurs hundreds of times a second These start life as normal binary systems with a pair of massive stars One of the pair collapses in a super nova to form a pulsar but if the binary system survives the enormous disruption of this event the pair can continue to orbit each other Much later the second star also collapses to form a pulsar but in so doing material ejected from the collapsing star may fall onto the first pulsar spinning it up through the conservation of angular momentum Although the first pulsar started with a very high magnetic flux this had declined over time and the reduced field now has little braking effect on its rapid rotation so the period of the associated radio pulses remains constant for an extremely long time He concluded with a discussion on the science and research that is possible from observing these incredibly accurate clo
22. including those examining the molecular spectrum of the Orion nebula which have revealed the presence in large quantities of organic compounds many of which are considered the precursors of more complex molecules Deep sky imaging in this spectral region allows the observation of the early stages of the universe as the light from this epoch has been red shifted into the FIR range as a result of cosmic expansion and reveals the great periods of star formation at this time SIDs SFEs and CMEs in 2012 As the Sun s cycle approaches its maximum John Cook presented details of notable events during 2012 His first chart illustrated the general increase in flare activity since 2010 followed by charts from Tarif Rashid Santo in Dhaka Bangladesh and Roberto Battaiola in Milan Italy showing a sequence of eight Sudden lonospheric Disturbance SID events on the 5 of July 2012 This M MIS ICE Nos pe right demonstrates the advantage of MiS 2i having observers in multiple time zones o M12 Mi3 M44 exi Solar flares can be associated with Coronal Mass Ejections CMEs and these can subsequently affect the Earth s magnetosphere Magnetometer 4 records from 2012 July 14 show the magnetic disturbance associated with the arrival of previously associated with a solar flare recorded as a SID on 2012 July 12 Compari
23. of radio astronomy seems to be leading more people to give it a go as an amateur science alongside the more traditional optical astronomy Editor s note This is a slightly shorter edited version of the review that appeared in the BAA Journal earlier this year RAGazine Sep 13 Using the AMSAT UK FUNcube Dongle Meteor Scatter Reception Paul Hyde g4csd yahoo co uk Introduction The following shows how a meteor scatter monitoring system can be put together using the FUNcube Dongle Pro the FCD Pro Plus Software Defined Radio receiver It was inspired by the series of papers produced by David Morgan and published on the BAA RAG website The aim here is to provide further information to enable those without electronics experience to monitor meteor activity including during daytime and cloudy sky conditions Note The original FCD Pro receiver requires different software for controlling the frequency and gain settings Details can be found at www funcubedongle com page id 313 This earlier design is no longer manufactured so can only be obtained second hand The remainder of this article deals with setting up the FCD Pro Plus and proving out the basic system followed by notes on how to do detailed analysis work on meteor echoes A future article will include details on constructing a suitable antenna for meteor scatter work Differences between the FUNcube Dongle and traditional receivers Previous meteor
24. overall these comments seem to apply to any chapter one picks Indeed discovered that one can dip into it on almost any page and pick up the thread and become completely engrossed International growth There is good insight into the personal and social lives of the earlier workers the problems with funding and military obsessions especially as the Cold War started the rather gentlemanly professional rivalries in a few places and how the community such as it was had great difficulty gaining the respect of the traditional optical astronomers astronomers in fact Sullivan chronicles the awful discrimination encoun tered by the only woman in the immediate postwar years to make a substantial contribution Ruby Payne Scott at CSIRO There are some fine orthogonal cuts taken through this large subject area too As one example there are separate sections on the various national teams around the globe that made significant and indeed lesser contributions with plenty of detail into their different styles their political and other problems their strengths and weaknesses all this in digestible form and quite separate from the general chronological thread of most of the book So one sees the developmental paths from different angles and vicariously through differing cultural assumptions There are some wonderful photos of early gear and lab book page copies to convey an immediacy to the narrative One significant photo record sho
25. scatter systems have been based around relatively expensive receivers used by short wave and air bands radio listeners Such receivers are the result of many decades of development and refinement to produce hardware specifically designed to pull weak radio signals from the aether By contrast the FUNcube Dongle is an example of a Software Defined Radio SDR receiver where some of the functionality is now provided by software based digital signal processing techniques running on a host computer The result is a small comparatively cheap device that is plugged into a USB port on a reasonable quality laptop or desktop computer The emphasis now shifts to installing and configuring software applications to process the data coming from the SDR receiver and this paper provides additional information to help do this Installing the FUNcube Dongle Pro Plus and SDR application Windows XP and later versions should automatically install the drivers for the FCD when the device is first plugged into a USB port The process may take a minute or so to complete It is highly recommended that you use a 1 to 3 metre USB extension lead and place the FCD away from the RF noise generated by the computer itself this is particularly true for laptops You then need an SDR application to be able to tune the receiver to the right frequency to receive meteor echoes and to process the resulting data The User Manual available from the official FCD website describes the
26. the editor with advance notice of any contribution The intended print view size is A4 The BAA is not responsible for the opinions expressed by contributors to The RAGazine and such published material does not necessarily express the views of the BAA Council or of RAG officers Copyrighted material may not be copied without the express permission of the author British Astronomical Assoc 2013 All rights reserved RAGazine Sep 13 Vol 1 Contents Coordinator s remarks Editor s remarks Book review Cosmic Noise by Sullivan D James VLF Quarterly observing report to July end 13 J Cook 12GHz amateur radio astronomy experiments J Rawlinson RAG at the National Museum of Computing August 11 13 P Hyde Amateur Radio Astronomy Group tracks Milky Way Hydrogen emission Low cost Hydrogen Line radio telescope for 160 using the RTL SDR P East Novice experiments with 1420MHz Hydrogen Line receiver components M Gawthorpe Improvements to a small radio telescope B Coleman Universities and other entities Light relief Advertisements Issue 1 Sep 13 14 20 22 23 31 34 37 38 40 Meeting of the RAG Oct 27 12 the Nat Space Centre Leicester D Swan 42 Using the AMSAT UK FUNcube Dongle for meteor scatter reception P Hyde Starbase log the clock L Newell Brief history of RAG What s on Home observer of the quarter Jonathan Rawlinson The UK Radio Astr
27. to overcome the lack of sensitivity A comparison of these devices in controlled experimental conditions gives a indication of their suitability for radio astronomy work These tests were based in the region of 1 42GHz using a home built hydrogen line simulator It appeared that these budget devices could be used for RA work although Control the FCD does offer better performance While Zero IF conducting these tests Tony also found E4000 RF RTL2832 vO Samples Tuner ADC useful test source in a geostationary Inmarsat satellite transmitting at 1 54 GHz with easily receivable telemetry channels He used G4DDK pre amps for this see the advertising feature in this issue As a final point Tony looked at the use of the new Raspberry Pi hardware platform with the budget receivers demonstrating that is possible to use this very cheap hardware to support RF and radio astronomy experiments Data processing and control Jeff Lashley s presentation addressed a common problem for many radio observers namely how to reliably log data over extended periods and make it accessible for post analysis When a radio telescope becomes operational the initial data is often collected directly from consoles and simple text log files Jeff has developed a solution based upon the inexpensive Arduino programmable platform which comes with a RAGazine Sep 13 range of input and output options and is programmable in BA
28. to minimise dish spillover mesh leakage side lobes and feed scatter The crucial factor is getting the best balance between spillover and uniform illumination of the dish It is not possible to achieve a feed design which has equal sensitivity to signals from the whole surface of the dish but which is totally oblivious to background noise coming around the edge The balance between illumination and spillover is significantly influenced by the ratio of focal length to diameter F D with a ratio RAGazine Sep 13 of 0 35 to 0 4 being optimum but this also needs to be considered in conjunction with the design of the feed Using figures for a typical 1 4 GHz system it was shown that controlling spillover was as important as optimising receiver performance demonstrating how crucial feed design can be Peter went on to consider feed designs including the simple circular wave guide often made from metal coffee tins rectangular horns resonant choke cavity Kumar feed horns multi ring feed and dual mode feed horns He illustrated how some of these can be manufactured using simple tools Similarly dishes of 4 to 6 metres in diameter can be easily made the secret being to achieve a strong hub structure and using plenty of ribs and rings Kumar feed under construction ai Using pulsars as cosmic clocks in the study of gravitational theories Prof Andrew Lyne Jodrell Bank Centre for Astrophysics started with a detailed
29. use of the SDR Sharp SDR application and this is probably the best approach for those not familiar with SDR systems There are several alternatives around such as HDSDR but SDR is relatively light on computer cpu loading leaving more available for analysing the FCD data The procedure for downloading and setting up the SDR application is described and illustrated in the official FCD User Manual You will probably be able to receive broadcast FM Wideband Frequency Modulation or WFM and Medium Wave Amplitude Modulation AM radio channels using the Meteor Scatter antenna even though it is not designed for these frequencies Be sure to use the correct 1 See www britastro org radio projects DM Meteor index html and www britastro org radio projects meteorproj html 2 See www funcubedongle com page id 1225 3 To find a list of these frequencies see www bbc co uk reception transmitters radio RAGazine Sep 13 demodulation setting top left hand of the SDR screen for the service you are trying to receive You should also familiarize yourself with the operation of the frequency Zoom and sensitivity Contrast slide controls on the right hand side of the screen Also useful are the amplitude modulated AM Airband frequencies carrying Air Traffic Control services Use the Approach channel frequency for your local international airport to confirm that you can receive these zs rer
30. ways to obtain an accurate Time is via the Network Time Protocol which accesses layers of time servers synchronised to atomic clock standards Starbase has an alternative clock called the NTPSynchronisedProxyClock which regularly adjusts a software clock as opposed to the computer s hardware clock to keep in step with the NTP reference time A simple algorithm attempts to work out the drift rate of the local clock and adjusts the clock rate to try to stay synchronised with the NTP master This should therefore remain accurate between synchronisation events It is important to realise that it does not affect the host computer hardware clock in any way Supposing that the clock is set to use NTPSynchronisedProxyClock see how this is done below then it will indicate 00 00 00 until the following Command is executed ObservatoryClock Utilities synchroniseNow The user may then set up a suitable synchronisation period using ObservatoryClock TimeProxy setSynchronisePeriod where represents the requested sync period in seconds Then start the automatically repeated synchronisation using ObservatoryClock TimeProxy synchroniseTimeProxy true true Watch the Synchroniser Chart Tab to see how accurately the clock is running or not If you have enabled debug messages you will see something like this in the console window target2clock action synchronise offset 127 msec driftrate 7 52 msec sec timestep 251 msec This softwar
31. with activity levels have tried to indicate periods where there is an easily seen disturbance of an hour or more in green and periods of sustained strong or rapid disturbance in red Yellow indicates a Solar Flare Effect SFE seen simultaneously with a flare They are not very common and are difficult to distinguish from local interference The presence of a SID is a good Clue but use the British Geological Survey Hartland bulletin as a guide to a genuine SFE The last SFE recorded was in 2012 August and even that was a debatable event Observers over the last 3 months were Roberto Battaiola Colin Clements John Cook Mark Edwards John Elliot Gordon Fiander Paul Hyde Bob Middlefell Steve Parkinson Gonzalo Vargas and John Wardle My thanks to all contributors Past copies of the monthly VLF summary can be found at www britastro org radio vlfreports html Fig 6 overleaf RAGazine Sep 13 BAA Radio Astronomy Group BARTEL DIAGRAM DISTURBED E ACTIVE B C M X FLARE MAGNITUDE SCOE Tota NON stan carrington s 2407 2408 BE gt CCMC MCMCC 2409 2410 2411 2412 2413 2414 2415 2416 2417 2010 November 2418 2419 2420 2421 2422 EN c NEM gt gt NEM CCC MMCC CCC CCC 12108 2423 CCCC CCCC CMMM CMM CMMM CCCC CCC BCCC CC CBCM CCCC 2424 NEM 05 9 1 CCCC CCCC CCCM CBCC CB 2425 EE z BBC CCC CCMCC 2426 2427 2428 20 ME ENS gt UE n
32. Redenham Observatory telescope is used for EME communications on amateur microwave bands between 3 4 and 24GHz so a variety of equipment needs to be fitted On the 10GHz and 24GHz bands the dish operates as a cassegrain system with the electronics located behind the dish and a feed horn illuminating a sub reflector To accommodate the different equipment at different positions a servo driven trolley is fitted so that focus can be adjusted The picture below shows the telescope equipped for 24GHz EME with the sub reflector and with a 24GHz horn fitted inside the original Ku band horn The electronics is to the rear at right The picture above shows the 1420MHz Dual Mode horn fitted to the focus trolley On the right the sub reflector is alternatively shown located on this focus trolley The system is brought into focus by aiming at the sun and using the trolley servo to adjust the position of the feed or sub reflector for a maximum RAGazine Sep 13 Universities and other entities Introduction This regular slot is intended to highlight interesting entities such as university departments and other institutions and organisations University of Hertford UH In the Physics Astronomy and Maths area this includes research in Astrophysics and Atmospheric Physics organised within the Centre for Atmos Physics CAR and the Centre for Atmospheric and Instrumentation Research CAIR inc extragalactic
33. SIC so requires no complex software development platforms or extensive software experience Once the data has been captured the next problem is presentation and analysis Spreadsheet packages such as Excel Open Office and Libre Office offer a range of functions and plotting tools but they can be restrictive and slow Jeff uses an application called which is a powerful statistical suite with many visualisation aids and options and is freely available for download Jeff had brought along a demonstration system but as is the way with all live demonstrations gremlins always seem to intervene However the approach Jeff presented demonstrated that the automation of interfacing radio telescope receivers with data loggers need not be too complex or expensive and certainly has a lot of potential for many radio telescope installations Practical considerations in meteor scatter observing In the final presentation of the day Paul Hyde discussed many of the practical issues associated with meteor scatter systems These use a distant transmitter that is not normally detectable at the receiver but where reflections from the ionised gas in the trail of the meteor can be received as a short burst of energy or ping Two useful transmitters for this work are the high power GRAVES radar near Dijon France and the much lower power BRAMS meteor scatter beacon at Dourbes Belgium In both cases the receiving station is quite straightforward using simp
34. an see that with a receiver noise figure of 5dB the FUNcube Dongle and a preamplifier specification of D 0 4dB 20dB gain are required to 0 8 achieve better than 0 5 system noise figure To go the whole hog to squeeze out the last 0 01dB performance from the preamplifier requires another 10dB of gain It s there if you want to use it but for the purposes of our experiments we didn t GHREEE SG 2E 385251 m m EN 22 A m E NEM HE NEG gm 33 2 20 10 F B 4 4 EFEREHERERE G2 N FEBHEPRESGaal BEEBE GREE GS gt e G e m u ERR ERE ESS EREREEeEE ERUYUEEEEE SUR DEEES uutu WNHEHEEN ERS ER ES BHREPERBEE H ER EUREEES The objective of the tests is to observe the difference in noise levels between cold sky and warm earth The difference in noise level dB will represent a quantitative measure of our system sensitivity Then using two preamplifiers each with known but different noise figure performance correlate the noise figure of the preamp to the system sensitivity For the novice this is a powerful experimental demonstration of the impact of lower system noise figure on system sensitivity The graphs below captured from Spectravue 5 show the noise levels demodulated by FUNcube Dongle as the cantenna is pointed vertically at cold sky hand held 2 5m above ground and then swung through 90 degrees to a hou
35. antenna sidelobe thermal noise intercepted 2l deg os 51195 10deq Sun ge ein n3 175deg GL155 04 9 a t t i GL145 25deg a vim x A ARR 4 z Xr 1419 14192 14194 1419 6 1419 f 142 1420 2 1420 4 1420 6 1420 8 1421 Figure 7 Improved performance with extra RF Gain Temperature calibration If G f is the power gain of the receiver as a function of frequency b is the receiver analysis bandwidth Ta the wanted signal equivalent temperature Trx the receiver noise temperature Tref the reference load temperature Tu the unwanted noise components background sky sun and ground temperature entering the antenna sidelobes Tc the noise generated in the antenna connecting cable and k is Boltzmann s constant RAGazine Sep 13 When switched to the reference input load the receiver output noise power is Pref k Tref Trx bG f When switched to the antenna the receiver output noise power is Psig k Ta Tc Trx bG f The ratio is simply Trx Tref Trx For example for the RTL dongle Tref 290 Trx 75 0 65dB amplifier noise figure 0 2dB switch loss and 0 2dB connectors And Tc 14 for 0 2dB antenna connector and cable losses Minimum and maximum ratios R seen in Figure 6 are 0 43 and 0 48 Therefore assuming the ratio 0 43 corresponds to no signal equivalent ground
36. as produced a very useful piece of software with called EMECalc with which it is possible to compare various dish and feed types Although primarily designed for evaluating amateur Earth Moon Earth EME communications systems it is also very useful for radio astronomers It can be downloaded free from Doug s web site In EME circles the usual Kumar feed is known as the VE4MA feed and this can be selected in Doug s program and the performance predicted Inspired by Peter Blair s talk at the RAG meeting in Leicester last year decided to try a different feed known as a Dual Mode feed This should reduce the system noise temperature by slightly under illuminating the dish and thus cutting down on ground noise This type of feed is known in EME circles as the W2IMU feed g Above A polar plot of the Dual Mode feed blue and the Kumar Feed red The red plot was abandoned to the rear due to jn M equipment failure it was a very cold day but note that at the edge 4 of the dish the Kumar feed illumination is about below that at the centre while the Dual Mode feed is between 10 and 15dB down The green line shows the extent of the dish f Left The Kumar feed is on the ground and the Dual Mode feed is on the tripod W2IMU feed Thinking of the system as a transmitter remember reciprocity applies the term dual mode describes the fact that the waveguide from which the radiation is launched supports two waveguide mod
37. at required when the pre amplifier is replaced with a 0 25dB noise figure device Total Receiver Gain Gain should be sufficient to ensure that the dongle ADC range is fully utilized This can be checked on screen using a relevant SDR software package such as SDR Temperature affects amplifier gain and because of the high effective system sensitivity there may be drift between successive measurements which can affect temperature calibration accuracy An optimum solution is for receiver baseplate temperature control The alternative is to wait for devices to warm up and shield the receiver from the sun and draughts FFT points and clock rate The data clock rate defines the dongle operating bandwidth equal to the clock rate for RTL and equal to half the clock rate for FCD The rule is that the more samples processed the better the frequency resolution The trade off is time The product of the bin width resolution and the data sample period is 1 The number of sample periods averaged is the integration time required to get a reasonable signal to noise ratio So the better the resolution required the longer the time is needed for the antenna to dwell on a chosen direction Since the line width of hydrogen is significant due to velocity variations of gas in the observed cloud there is a sensible limit to the resolution required to infer cloud velocity components Conclusions It appears that this basic technique using a simple antenna can provi
38. b primer on the techniques and astrophysics of early radio astronomy especially on phase switching and interferometry Here is a partial listing of chapter headings and some selected sub headers to convey some feel for scope and depth of this erudite book Searching for solar Hertzian waves Hertz Edison amp Kenelly Lodge Wilsing amp Schneider Nor dmann why no one discovered solar radio waves until 4 decades after Nordmann Jansky and his star static early years the setting for Jansky s work investigations later years reaction of the scientific community was Jan sky stopped by Friis why did Jansky succeed Grote Reber science in your backyard the man and his dish etc Wartime discoveries of the radio sun radar development Hey other wartime sun incidents pre war observations Appleton controversy Southworth and the quiet sun group postwar Radiophysics Lab Sydney Ryle s group at the Cavendish Lovell at Jodrell RAGazine Sep 13 Meteor radar Reaching for the moon Theories of galactic noise The 21 cm hydrogen line Most chapters are around 25 pp or so each Basically the coverage is up to 1953 although there is plenty of mention of later developments to set matters in context have read many accounts of my personal hero Grote Reber but that here is the most comprehensive detailed and rounded that have yet encountered It is also delightfully easy to read and
39. cks moving in gravitational fields The precision with which the binary orbital parameters can be determined suggest that their orbits are shrinking by 1 cm per day the resulting energy loss being transferred to gravity waves Since the pulsar frequencies are extremely stable the Doppler shift due to orbital movement pulsar positions and mass can be determined very accurately allowing investigation of relativistic effects space time distortion Shapiro delay and the principles of orbital decay through gravity radiation Outreach via hydrogen line astronomy After starting with a brief history of radio astronomy Brian Coleman talked about the physics behind the neutral hydrogen emission line The emission at 1 420405 GHz corresponds to the photon emitted when an electron in the hydrogen atom reverses its direction of spin to be opposite that of the proton nucleus However detection of this emission requires very large volumes of hydrogen gas and in spiral galaxies the greatest mass of neutral hydrogen can be found in the arm structures RAGazine Sep 13 Brian presented set of observations made looking across the galactic plane The technique is for the antenna to track the target whilst the receiver is tuned across a range of frequencies spanning the hydrogen emission line The Doppler shift created by the relative motion of the observer and source is then expressed as a radial velocity and when this is plotted against the signal
40. crete front and titers A20MHz i01 9GHr bur this new design has on board fiters for the kraai services or products offered individual through xm ence T ppm TEXO ice i y 149 commercial so long as it s at least in part Much improved phasa The price is only 149 99 Dynamic Range by up io For a full review see Radiother December i i TdB POL eua related to radio astronomy and geophysics and Turer PLL Saa memory d T All ea pius more and si no Sereno SER DUI WEA on that the editor s decision is final Pelis www hamradio co uk funcube Contact dave greenover net RN nnm Martin Lynch Sons Lid OPENING HOURS 01769 561 002 Outline House 7 3 Cuullcitond Street Monday io Friday 8 DOam to 3 30pm Chertsey Sure 845 9 30m to 4 300m ive www hamradio co uk Tel 0345 2300 599 amp aleschamracdio co uk iat 44 346 Z300 ERU RAGazine Sep 13 Advertisement feature Very Low Noise Amplifiers for 1420MHz 21cm VLNA21 Developed for amateur radio moonbounce operation the VLNA range of kits includes the VLNA21 radio astronomy LNA in a low cost un cooled design These preamplifiers are used around the world between 432MHz and 3400MHz by moonbounce enthusiasts and by both amateur and professional radio astronomers at 1420MHz Each VLNA21 incorporates a two stage P HEMT
41. crosoft Excel s matrix function This produced an image of the sun at 12GHz with minimal amateur equipment Radio Image of the Sun 12 GHz 3 amp 2 25 gt Radio image taken with a 1 2m dish note the visible scan lines across the image due to the low quality ADC only 10 bit To move the dish realigned the conventional equatorial satellite dish rotator into elevation only below then calculated where the sun would be in the sky and used the old dish rotator electronics to move the dish up and down This means that was able to continuously scan a strip of sky using the earth s rotation as an azimuth drive Than calculated the speed that my beam moved across the sky and used this value to calculate how many degrees a sample represented This means that was able to assign a scale to my image RENE EIU A temperature mapping To do this did another scan of the sun using my dish using a similar set up to my 0 6 M dish telescope but with a few important changes http seetron com archive html ht tip1 htm RAGazine Sep 13 Funcube Dongle FCD is used as a receiver instead of a satellite finder This is because with the satellite finder and Arduino combination only get low sensitivity and high temperature fluctuation This is due to the satellite finder not being designed to be a telescope receiver but a simple piece of equipment to detect satellites You only get so much for your mo
42. cture describing the work that amateur enthusiasts could undertake The BAA Radio and Electronics Section was duly set up with John Heywood as its first Director Contributors included Frank Hyde who made the first amateur observations of the Crab Nebula being occulted by the solar corona in 1959 and who wrote the fine early guide Radio Astronomy for Amateurs Frank also provided the regular Spacewatch column for Practical Electronics magazine Another notable figure was John Smith who took over the leadership of the renamed Radio Astronomy Section from 1964 through to 1977 and was a major force in encouraging amateur involvement in the field Sadly after John died interest waned and the Section ceased to operate However in 1994 the current Radio Astronomy Group was created with Gordon Brown as its coordinator later to be followed by Peter King Laurence Newell and currently Paul Hyde In 1996 these had been the declared observers already encompassing geophysical as well as strictly radio astronomy Table 1 List of observers measurements J Hale Phase switched interferometer 137 5 MHz Hatfield Full power systems 136 1297 3 MHz T Hopwood Particle propagation magnetic neutron amp L V detectors D King Phase switched interferometer 150 MHz receiver J Long SAE receiver 18 3 KHz J Marsh Full power system 151 MHz R Middlefell Whistlers I R Smith Phase switched interferormeter 178 MH
43. de a useful platform for detecting and studying the hydrogen line It is evident that smaller beamwidth more efficient antennas would considerably improve the data quality Comparing dongles the broader bandwidth of the Realtek RTL device makes this a better choice Comparing SDR software both FCD and RTL dongles can be used with SDR but the software is not well matched for hydrogen line radio astronomy FFT averaging of hundreds of thousands of samples is required to achieve the required sensitivity but the SDR software has only a limited averaging form opectraVue does not support the RTL dongle but has a good averaging function although FFT size is too large and very long observation times probably requiring tracking may be necessary unless of course you are blessed with a multi metre dish Both software packages do provide a raw data file output in wav format that can be processed off line RAFFT exe provides this function but in its basic form reverses the spectrum and may slightly corrupt the data by processing the header The plan is to update RAFFT exe to operate correctly on wav files More information available at http www y1pwe co uk RAProgs index html Final Observation From an amateur s point of view there appears to be an optimum solution for detection and analysis of hydrogen in the arms of our galaxy the RTL receiver and processing as described but using an antenna with around 2m aperture beamwidth of the order of 6deg
44. e signal received from the antenna In a Dicke switched receiver this is toggled at audio rates and integrated in an analogue manner It is simpler in a digital system to average the received spectrum output first for the signal followed by the reference and carry out the comparison in subsequent file processing in Excel for example In fact the switch may not be necessary and the switch loss avoided if the user is prepared to disconnect the antenna and fit a matched load to the receiver input and integrate to obtain the reference measurement Amplifiers 110 These are Minicircuits ZX60 162LN about 20dB gain and 0 6dB noise figure at 1 4GHz They each require 4V at 50mA A reasonably cheap power supply solution was a 20VA 230V primary 9V secondary transformer and a Voltage Regulator kit AC in DC out and based on the LM317 both procured via eBay The Minicircuits amplifiers cost about 46 each VAT and postage Lower noise figure 0 25dB amplifiers are apparently available from S Jewell G4DDK at around 50 for each kit Filter 20 cables and connectors 5 The narrow band filter was designed using the excellent internet calculator by D Heatherington WA4DSY and following construction ideas from the Utah ATV opted for 5MHz O 1dB bandwidth 3 element filter A 0 9mm copper sheet was cut out and bent around appropriately sized wooden blocks for the box and lid with 14 gauge tinned copper wire cut for the i
45. e a talk on radio astronomy find an audience that is genuinely receptive to the subject and fascinated by how it has provided such a different view of the universe This year marks the eightieth birthday of radio astronomy as marked by the New York Times front page article on Karl Jansky s discovery that the mysterious additional static he was hearing had a period of 23 hours and 56 minutes and was coming from the direction of the centre of the Milky Way There are high profile science projects such as ALMA LOFAR and the SKA which are increasing public awareness of the subject whilst techniques such as software defined radio are making it easier for the amateur to become involved and the internet offers fantastic access to both amateur and professional science resources Whilst don t expect to see a rapid uptake of 2 4m dishes in back gardens do believe there is scope for wider interest in areas such as meteor scatter Jupiter emissions and solar space weather work Finally would like to thank Dave James for volunteering to be Editor for this newsletter It does take time to put these things together and hope that people will help Dave by contributing material as often as possible Best wishes Paul Hyde BAA RAG Coordinator g4csd yahoo co uk RAGazine Sep 13 Editor s Remarks First the title RAGazine this has been chosen to help convey the notion that this is planned to be a little different from most newslett
46. e is very much under development and could be improved considerably with a bit more effort One improvement would be to expose the tuning parameters of the clock steering algorithm via Command settings so that the users can experiment to fine tune the clock All in good time Start here http www ntp org for a discussion of NTP and many useful links to other resources Please remember not to hit an NTP server too frequently This would be regarded as bad netiquette It would be easy to create a clock synchronised every second by NTP but you would soon find that it wouldn t be a popular implementation The results of some initial tests of the algorithm are shown below The clock starts up a few seconds in error but rapidly settles to within about 100msec This is almost certainly good enough for our uses but more accuracy might be obtainable pisem aare Clack and nerak Hime Clock Drift adjusted using NTP Ree eee eee ps RAGazine Sep 13 So suppose we did need extra accuracy or just wanted to experiment with other time standards The clocks we have mentioned the SimplePlatformClock and the NTPSynchronisedProxyClock are written as Java Data Access Objects DAO This means that the software obtains the data it needs from this object and that object alone is responsible for gathering the information in this case the Time from the outside world Creating anothe
47. e meantime the full description of a Command is called its Starscript in anticipation of such a language structured as below Instrument Module Command ParameterA ParameterB RAGazine Sep 13 Modules Observatory Clock Modules Ephemerides TimePraxy MetadataManauger Exporter Utilities Core Several of the clock Modules are common to all instruments so we ll concentrate on the clock s features The Ephemerides Module simply duplicates the functions of the Ephemeris Tab so that in principle it is possible to generate an ephemeris programmatically This may one day be useful for e g automatic control of antenna position The TimeProxy Module is under development and is described in the Expert User section below The Utilities Commands appear as shown below ietDiate Utilities Commands These are very straightforward For instance if you need to get the Time as opposed to just looking at the clock then execute the following Starscript Command ObservatoryClock Utilities getTime Where the empty parentheses show that no Parameters are required The response to the Command will be returned on the Response tab and also in the Command Log window The Response may be copied to the clipboard and then pasted into other applications This operation may seem rather trivial at the moment but it is the first step to putting into place the ability to execute Commands automatically
48. e range of the antenna Personal Computer clock systems radiate significantly in band and local wifi smartphones smart tv and iPads etc should be treated with suspicion Wrap the dongle in aluminium foil and build a foil covered box to house the laptop Antenna Beamwidth is approximately 60 d degrees where d is the aperture in wavelengths RAGazine Sep 13 Hydrogen clouds in galactic arms lie within about 5deg latitude so antennas with this beamwidth can be expected to have good temperature detection and moderate angular resolution Beamwidths greater than this lose out on resolution but more importantly on detection and temperature measurement loss equivalent to the proportion of beam not illuminated in latitude Wide beamwidth antennas also tend to allow greater unwanted ground noise into the system through sidelobes Narrower beamwidths have full temperature sensing ability can control spillover loss and are also able to resolve temperature variations in latitude and longitude RF Amplifier Noise Figure Generally the lower the better below 1dB noise figure however the benefit of further reducing noise figure may not be very evident for broad beamwidth antennas whose back and sidelobes illuminate the ground and local warm features so raising the system temperature For example to obtain the same temperature uncertainty the integration time for the system described with 0 65dB noise figure might only have to be double th
49. ecords but using browser applet viewers can be very slow to analyse large data blocks The alternative RAFFT exe FFT averager program is written in C and is about 30 times faster averaging data in about the same time as for the data acquisition Since both signal and system noise are both zero mean random noise there is little benefit gained from input data windowing such as Hanning etc before computing the FFT spectrum 0 48 4 1419 1419 3 1419 4 1419 6 1419 8 1420 1420 2 1420 4 1420 45 1420 8 1421 Figure 6 RTL2832U dongle receiver 256 point spectra for Galactic Longitude 145 Figure 6 shows the Figure 1 receiver response when directed at Galactic Longitude 145 for two 97sec periods The first period collected data using OsmoCom software rtl sdr exe to output a bin file with alternate and Q amplitude data via the antenna The resulting file was then processed by C programmed software RAFFT exe this inputs the bin file and carries out almost 400 000 256 point FFTs and averages these to improve the temperature sensitivity over 600 times The second period collects similar data when the receiver input is terminated by a reference load Figure 6 plots the ratio of the two resulting averaged FFTs processed by the RAFFT exe program The central spike is a dc offset feature and the central broadening is due to dongle VCO noise and it is also noted a few s
50. er s antenna characteristics with the aim of producing a display similar to the following E Left Meteor reflections captured using the basic activity monitoring settings RAGazine Sep 13 Above Meteor reflections captured using the basic activity monitoring settings To capture more detail of individual events go to the Spectrum Display Settings screen under Options in the top menu and decrease the Waterfall Scroll interval from 200 to 50 milliseconds Also change the Waterfall Time Grid from 30 seconds to 10 seconds Spectrum Lab s Conditional Actions CA feature can be used to log activity and save screenshots and audio recordings of individual events The CA script included in my standard Spectrum Lab configuration file triggers a screen capture when it registers a signal within the range of 2 9 to 4 kHz that is more than 17 dB higher than the background noise This reference against background noise helps prevent false triggers due to bursts of wideband interference This trigger level of 17 dB may need adjusting to match local conditions Too small a value will risk false triggers from phenomena such as moon bounce and tropospheric scatter signals Too large a value will miss the smaller meteor events To enable Conditional Actions check the Active box in the top left hand corner of the Conditional Actions screen under the File tab in the Main Menu bar The CA script is a simplified version of that develo
51. ers and in particular the fairly short and often quite formal ones produced by some BAA Sections and to some extent the four Baseline issue published in 2005 6 don t think Ragazine has yet reached Merriam Webster s dictionary but its widely used to denote a cheaply produced magazine So we publish electronically and its a play on words And it s quarterly and intended to be informally user friendly Importantly the intention is to encourage the inclusion of a wide variety of material a fairly balanced mix to suit newcomers up to experienced instrument makers and observers This also includes relevant material on historical educational hardware software science and technology aspects book reviews outreach practical hints and tips forthcoming events as well as related recent news on astronomy cosmology and so on In most issues and commencing with this one it is planned to feature a member s or group s observatory and this could mean a back room with RF cable to the garden as shown by Peter East in this issue think you will be inspired by this month s choice of young Jonathan Rawlinson also make no apology for including some whimsical and orthogonal material to hopefully amuse and entertain Unfortunately my own humour can be hard to fathom at times my wife in particular tells me so for the wider benefit you should definitely submit some great alternative inputs So PLEASE do not assume that a few hard pressed individuals
52. es which result RAGazine Sep 13 in zero current flowing at its rim This reduces side lobes and thus ground Again thinking of the system as a transmit antenna the RF is first launched into a normal circular waveguide section of sufficient length to establish the normal single waveguide mode A carefully designed taper connects this to the larger size of waveguide which can support the two modes required allowing sufficient length within the guide for those modes to develop The sizes of a W2IMU feed designed for 1296MHz the 23cm amateur band were scaled and with help from lan Lever G8CPJ who marked out the aluminium sheet and cut the circular shape needed for the cone set about making the feed horn My metalworking capabilities are not great but construction was not too difficult using pop rivets and aluminium solder have a small 305mm shear roller and bending machine Axminster Power Tools which was put to good use forming the circular waveguide sections and especially the cone see left The probe was made to a little over the scaled length then adjusted for ae return loss at the edges of the band of interest 1418 1422MHZ Putting these feed types into Doug s program along with the details of my dish and LNA etc a Tsys of 57K is predicted for the Dual Mode W2IMU feed and 87K for the more usual Kumar feed So this is a considerable improvement pe Receiver Parformance Source Po
53. estigations from listening to bat calls to monitoring VLF radio transmissions for Sudden lonospheric Disturbances SIDs This continued development has left it with a mass of adjustable parameters that present quite a learning curve and makes it more difficult to set up than SDR However it does have a very flexible system for automatically detecting and recording events and associated data as well as capturing screen and audio file saves for later investigation Spectrum Lab does not have the functionality to control the Frequency and Gain settings and you need an additional application for this This can be the simple FCD Frequency Control Program available from the FCD Pro Plus download page This has the advantage of not using any cpu capacity in normal use leaving the maximum available for processing the meteor pings Setting up the FCD for meteor scatter If you haven t done so already plug the FCD using a USB extension lead into the Host computer Save the FCD Frequency Control Program to your host computer and then open the application You should be rewarded with the following screen FUNcube Dongle Prot Control V7 0 HiDOpen cf Vid OMdfkPid fbi returns 1 Success FCD Found HIDWriteC command returns 1 Success FCD write register Current Frequency Left FCD Frequency Control Program with recommended frequency setting of 143 047 MHz Set def aukts Satch to bootinsder RF Fiter Mier i
54. f Amateur Radio Astronomers to usefully share experience in the publishing of their Journal and this Sometimes as for this month articles will be co published and this time it is two which happen to be of UK origin but at other times either publication may by agreement carry material that may have already appeared in the other An example of the latter is the first of several back to basics articles by Jon Wallace from the SARA J that will appear in the next issue of RAGazine would also like to solicit at least one or two contributing editors or correspondents for specific areas PLEASE take note and consider volunteering Certainly there is enormous talent and enthusiasm in this space and will try my best to support you all as RAGazine editor PLEASE spread the word about RAG BAA and the RAGazine And PLEASE give Paul Hyde or myself feedback good or bad Best wishes Dave James Editor dave reenover net RAGazine Sep 13 Cosmic Noise by W T Sullivan Book Review Dave James dave greenover net Ahead of the Contents section of his monumental tome Sullivan includes this lovely quotation that sets the scene exquisitely had the opportunity only yesterday of watching Sagittarius rise in broad daylight on the needle of a millivoltmeter It is certainly gratifying to see gunlaying radar apparatus put to such uses Alan Hunter Royal Greenwich Obs Oct 1946 Cosmic Noise B n A Histo
55. g about the John Smith All Sky Survey Dr David Morgan s website Hans Michlmayr s website and especially the project about radio astronomy at 81 MHz from Colin Clements hosted on the britastro website have also been motivated by my radio club who do a wide range of radio astronomy related activities After reading widely into the topic decided that was bored of reading about what other people have done and wanted to receive signals from the earth and beyond with my own equipment must also mention a great friend and mentor Stuart Constable who runs QRZ ARGOS and who has been a constant source of knowledge and encouragement right from the start of my adventure into amateur radio and amateur science would be nowhere without him 12 GHz amateur radio experiments My amateur radio club QRZ ARGOS based at the Herstmonceux Science Centre in East Sussex has been using an Itty Bitty Telescope for 12 GHz Ku as a display at the Herstmonceux Science Centre open evenings Although it is in no way a professional telescope designed for accurate observations it gives a good base for explaining how a conventional total power radio telescope works to the public was very interested in this technology and wanted to take it further started with reading more about the Itty Bitty Telescope by NRAO and decided to build a slightly bigger version with a 60 cm satellite dish ordered from Amazon for
56. g arresters with bleed to ground to reduce noise Most RF line arrestors feature a low capacitance shunt discharge tube alone Some radio amateurs and amateur radio astronomers actually use them most don t One low loss design worth looking at also features a high voltage series capacitor and most importantly an antenna side toroidal shunt inductor The intention here is to bleed static continuously to minimise receive noise in lively conditions but before any main strike static The military and security agencies seem to be big users Some models go to 1 5 GHz some have fast varistors as well The supplier Morgan Mfg USA www morganmfg us RAGazine Sep 13 Improvements to Small Radio Telescope Brian Coleman brian coleman tiscali co uk Background The usual choice for a feed horn for amateur radio astronomy is the Kumar feed which consists of a short section of circular waveguide fitted with a choke ring The waveguide on its own produces a very broad beam The scalar ring or choke is excited with modes which produce a pattern which is more square and thus more efficient and illuminates the dish rather evenly without much loss at the edges This may be good for transmit but means that the feed is seeing the ground behind the dish raising the system noise temperature My dish has a focal length of 1 6m and its diameter is 3 7m so the ratio f D is 0 43 Doug McArthur VK3UM www vk3um com h
57. han RAGazine Sep 13 The UK Radio Astronomy Association UKRAA Ast Tum The UK Radio Astronomy Association UKRAA is a charitable company limited by guarantee It was formed in 2008 as a spin off from the Radio Astronomy Group of the British Astronomical Association Its objects are to promote the science of radio astronomy and all branches of radio astronomical research in practice its primary purpose is to make and sell radio astronomy modules UKRAA s website is at www ukraa com This includes an online store where you can purchase UKRAA products and radio astronomy books a download area where product manuals are available and a Starbase section Our main products are Very Low Frequency Receiver The VLF Receiver is designed to record Sudden lonospheric Disturbance induced by solar flares It does this by monitoring transmissions from Earth based beacons which are affected by changes in the ionosphere giving an indirect indication of events on the Sun The main motivation for this work is to correlate the radio observations of solar activity with those from optical observers and to follow the cycle of sunspots as they appear on the oun This unit was originally designed by Peter King for the BAA Radio Astronomy group RAG and modified into its current form by John Cook Magnetometer This is a highly sensitive 2 axis instrument for measuring changes in the Earth s magnetic field partic
58. is is a self perpetuating state of affairs One of the Group s objectives is to change that but the Journal will never be appropriate for publishing detailed descriptions of hardware and software These are areas best covered through this Newsletter and the hope is that individuals will pass on their experience in this way As the RAGazine name implies the newsletter is intended as a more informal means of publishing information as compared to the Baseline we published a few years ago The hope is that we can still do something like Baseline perhaps on an annual basis drawing upon the ideas and content originally provided through this RAGazine Some of that material would also be submitted for publishing via the BAA Journal to highlight the value of radio astronomy and the work being carried out by amateurs The Radio Astronomy Group does have an organising committee which mostly functions via email but does hold meetings three or four times a year Depending upon the relative timing will use this column to provide a summary of what was discussed and the ideas put forward with the intention of getting the views of the wider membership More than anything we would like feedback from readers on what they think of this newsletter and what they would like to see coming out of the Group Amateur radio astronomy has had a chequered history in the UK but my belief is that this is down to a lack of focus rather than a lack of interest Whenever giv
59. it to this new UH facility please contact Dave James at dave greenover net Ref www herts ac uk research stri RAGazine Sep 13 Light relief Science down at the farm A farmer is having problems with his chickens All of the sudden they are all getting very sick and he doesn t know what is wrong with them After trying all conventional means he calls a biologist a chemist and a physicist to see if they can figure out what is wrong So the biologist looks at the chickens examines them a bit and says he has no clue what could be wrong with them Then the chemist takes some tests and makes some measurements but he can t come to any conclusions either So the physicist tries He stands there and looks at the chickens for a long time without touching them Then all of the sudden he starts scribbling away in a notebook Finally after several gruesome calculations he exclaims l ve got it But it only works for spherical chickens a vacuum Tricky PR Reported common exchange Ah hear you are interested in astrology 7 No astronomy Especially radio astronomy and geophysics Uh radio You mean wireless Yep using radio emissions instead of optical ones how does that work What you see Well you can t just buy a radio telescope as you can for an optical one And it s not quite easy to observe a fine picture the obvious way that we do with a normal telescope bu
60. lar way also showing a double dip response from sky ground wave interference effects This flare also produced a strong CME that was recorded as a Sudden Storm Commencement SSC at 18 10UT on the 24 With both the SID and SSC recorded we can measure the transit time Sun to Earth as 52h 44m The subsequent magnetic disturbance lasted until midday on the 25 As can be seen in the activity chart previous page the SID count in June was only a third of that in May There were no X class flares to record and only three M class flares recorded as SIDs The M2 9 flare late in the evening of June 23 HOLH M23 SID 1013 June 24rd Mark Edwards as recorded by Mark Ed wards is shown in Fig 4 be low This was recorded at 24kHz the transmitter being located Maine USA The des trans Atlantic path allowed w this late evening SID to be PE recorded when the European z paths were already past sun i T set L T T T T T anc m zx m anum XI il rae i 1202 5 eG rm Ern A small SSC was recorded at 04 26UT on June 23rd as an 18nT transient The Space Weather Prediction Centre SWPC indicates that another M2 9 flare at 03 14UT on the 21 was responsible giving a Sun to Earth transit time of 49h 12m The flare itself was not recorded as it occurred during the night Activity increased a little in July with 45 flares being rec
61. le aerials and a standard communications receiver or the FUNcube Dongle Free software can be used to record and process the signal the Spectrum Lab application is particularly useful for automatically capturing data and screen images for individual meteor events Paul concluded his presentation with some typical observations revealing the deceleration of the meteor in the direction of line of sight via the rapidly changing frequency of the reflected signal Reflections from the plasma trail can last for tens of seconds providing an indication of the different sizes of the meteoroid particle whilst the number of reflections provides information on the profile of individual meteor showers unaffected by daylight or cloudy conditions This type of observation is easily accessible and relatively easy to automate making it an ideal project for beginners and schools wishing to participate 20120816 0405 oe Closing Remarks 20120813 0904 The day s proceedings concluded by Paul Hyde thanking all of the speakers and helpers particularly Jeff Lashley for arranging the venue As always the audience consisted of both amateur astronomers and radio amateurs Observations made using the GRAVES radar transmitter at 143 05 MHz and the enthusiastic discussions at the breaks and at the close demonstrated that there is a healthy collaboration between these individuals A mixture of new hardware good open source software and a growing awareness
62. less than 50 This package contained the LNB dish and satellite finder all of which are required for the construction of an Itty Bitty Telescope then set it up with an Arduino monitoring the voltage output from the satellite finder sending the data to a PC for logging The scripts for doing this will shortly be available on my website www qsl net mO0zjo The figure overleaf shows the block diagram 1 www dmradas co uk 2 www wavelab homestead com 3 www britastro org radio projects clements81mhzreciever pdf 4 en wikipedia org wiki Ku_band gt www gb nrao edu epo ambassadors ibtmanualshort pdf 6 www arduino cc RAGazine Sep 13 Outside Radio Shack Long coax run indoors Diagram of the simple radio telescope This worked quite well and was getting strong responses from the sun but also massive temperature effects from the temperature instability in the LNB satellite finder and Arduino Below is an example of this This graph was taken over nearly 5 days and the majority of the signal represents the temperature of the sky or the local temperature interference sadly not astronomical sources The dish was deliberately aimed so that the sun would not pass through the beam on BH TE UT ry EE RA EEr CY T Column 1 1000 800 5 8 600 5 Illustration Effect of E temperature on the telescope The dish v
63. mplifiers broadband 5kHz through 2 5GHz flat gain Very low noise amplifiers for amateur and radio astronomy bands Bias tee and SOR splitter 5MHz through 2 5GHz 200mA DC rating RFD representative Kevin G3AAF E Mail kevini amp avery03 fsnet co uk For product details please visit www gBfek com RF HAMDESi Microwave Equipment amp Parts www rfhamdesign com Wwww wavenode nl Radio Communication Antennas amp Associated Products ip m abd rm amin Trt il r fe P rm p i i s de doe Ue UMEN 0345 2900 599 System Components FUNcube Dongle for Microwave Radio Amateurs MA Bat ord ess tn cect bn lightning fast parked of time by irs inventor Howard www chris bartram co uk ee Alter the naccees of the FLiNcube Modern Microwave Technology from GW4DGU podus uel gt ENEMY ew Howard Long the FUNcube mrenion deoded 10 hho account feeb by mary FCD users wih ha calling the FUNcube Dongle Pro Howard traria hat you wil fat the resuts anre 0 do we Then Coverage i Pom 150KHr fyes mam enhancements both performance Your advert could appear here CELERE Ld TELE oar dini i i to 410MHz There a gap INTRODUCING THE EXTENDED RANGE anywhere cina eer tha Pe a bra n gura Bani All adverts are free wanted for sale exchange Elvan dis
64. n display As it was highly unlikely that Jupiter would oblige with a perfectly timed set of radio bursts a series of audio recordings were used to demonstrate typical short and long forms of radio bursts There were a couple of VLF receivers on display and we managed to monitor Skelton Anthorn and Ramsloh This was something of a surprise given the tremendously noisy local environment There were at least 20 elderly BBC Micro computers and monitors live in the same room as our equipment plus a computer controlled electric railway set The National Museum of Computing has a number of large electrically powered and elderly exhibits so it wouldn t have been too much of a surprise if all the live demonstrations had been overwhelmed with noise Outside alongside the various optical telescopes Andrew Lutley demonstrated the use of a domestic satellite dish and a modified satellite finder meter for monitoring solar emissions at 12 GHz This simple equipment can be used to show the differences between radio emissions from the sun the cold sky and even the human body The live demonstrations were supported with poster displays plus a collection of audio files of meteor pings Jupiter and solar noise bursts and a selection of pulsar recordings The audio files proved popular with passing trade whilst the posters were a good resource for explaining the principles of SID solar radio burst and meteor scatter reception RAGazine Sep 13
65. ney The PC is using Spectravue instead of Hyper terminal as the data collection software This is because the Funcube Dongle is a Software Defined Radio SDR and requires software to use it opectravue can be used for many other applications in the SDR world A line power inserter is included The Low Noise Block LNB on the dish requires power to run as there are amplifiers and frequency converters contained within the LNB The line power inserter allows 12 to get to the LNB but protects the Funcube Dongle A power inserter was not required before as the satellite finder includes one in its internal circuits The method used to capture my data is the same as the method Dr David Morgan described using the Funcube Dongle for total power galaxy observations A flow diagram is shown below Outside Radio Shack Long coax run indoors A diagram of the more complex radio telescope The image produced with the above set up is shown below The image was created with 19 vertical scan lines The software used to plot the image was the script will soon be available on my website In the sky the sun has an angular size of about 0 5 degrees As you can see from my image the sun looks much larger than that about 3 5 degrees This is because my dish sadly doesn t have an infinitely small beam width and therefore the beam width overlaps and covers other parts of the sky making the sun look bigger The scale on
66. ney so they took advantage of the plethora of war surplus electronics available for a song They were of course familiar with the British equipment but Ryle also knew which German equipment was desirable Moreover a German item was easier to acquire because it didn t have a serial number on it that needed processing a bureaucrat fact during the war he Ryle could even tell whether an unknown transmitter was British or German because the Germans frequency stability was marked ly superior RAGazine Sep 13 Five truckloads of surplus gear were looted from a depot at the Royal Aircraft Establishment RAE at Farnborough The most spectacular finds were several 3m and 7 5m diameter Wurzburg dishes which later played an important part in solar and radio source measurements As Ryle later recalled We went to RAE to arrange for the transport of the Wurzburgs but found they d unfortunately just been sold to a scrap metal merchant which was sad But we drove around to see the merchant and he was a very nice chap When told him we wanted them for scientific research he said You can have them like science We swapped them for some other stuff and we all parted happily But then we were in a bit of a fix because gifts to the University of Cambridge have to be recited in the Senate House in Latin and we weren t quite sure how we d translate all this stuff about German radar sets
67. ng the timing of these events gave a transit time of just under 50 hours equating to an average velocity of just over 800 m s below left data from P Hyde Basingstoke 1 Finally John provided charts showing a potential Ree JA JU Solar Flare Effect event or SFE 2012 August un T I SENTO ev 16 These are short duration localised changes in the earth s magnetic field associated with very energetic solar flares However the flare here SID duly 12h ME SQUT wt 22 Tie was a lowly C class rather than an M or X class CME July 14th 18 09UT event suggesting that the timing of the magnetic Transit time 49h 36m 49h 57m B38m s anomaly was coincidental John was thus surprised when the BGS station at Hartland reported it as an SFE event He has since been corresponding with the BGS team and he reported that the professional community is still split over whether this was a true SFE event or due to more mundane perturbations in the magnetosphere Next Generation Radio Astronomy At last year s meeting Noah Hardwicke a student at Monmouth School described the next stage of development for the school s VLF solar observation programme and he now presented some of the observations of Sudden lonospheric Disturbance SID events processed and charted using Excel RAGazine Sep 13 These were compared with results from other observers and from the GOES satellite which monitors x ray activity fr
68. ngly my university prof was another F Hyde but Paul and the earlier two are all unrelated RAGazine Sep 13 What s On Saturday 7 September National Space Centre Leicester 5 SOLD OUT NS 2S A one day workshop showing how a low cost satellite finder meter can be modified for use with a satellite dish to observe radio emissions from the sun Saturday 12 October St Mary s College Bexhill on Sea An introductory talk by Paul Hyde on amateur radio astronomy as part of the BAA s Back to Basics meeting See http britastro org pdf 2012 Bexhill B2B Booking Final pdf for more details Thursday 28 November Basingstoke Astronomical Society Practical Amateur Radio Astronomy Paul Hyde See htip www basingstokeas org uk for meeting location and details RAGazine Sep 13 Home Observer of the Quarter Jonathan Rawlinson Observer of the quarter As indicated elsewhere in this issue 72GHz Amateur Radio Experiments Jonathan has just successfully completed his A Levels He tells us that he is taking a job for a year at DSTL the defence technology company before starting a physics degree course He lives on a farm in Kent in the S East so he seems to have enough room for expansion These pictures show him with the 12GHz receiver and also his home made corner reflector design which he will update us on in a later issue Oh yes and the troublesome sheep Best wishes to Jonat
69. nterdigital elements and with SMA connectors used for input and output The input and output connections to the elements needed care to solder as they were about 1mm from the element box end as is evident from Figure 4 right RAGazine Sep 13 Tuning is easy for a 3 element first you maximise the centre element then trim the outers using the dongle with SDR software and whilst monitoring the displayed receiver noise level By tuning the dongle centre frequency in 1MHz increments either side of 1420MHz the receiver noise amplitude follows the filter characteristic Performance achieved was 6MHz 0 1dB ripple bandwidth and 16MHz 20dB bandwidth Initially this filter tuned 10 MHz but by shortening the centre element obvious as the tuning screw fell out success was achieved Minicircuits offer a filter with 100MHz bandpass from 1350 to 1450MHz but the filter roll off is too slow to effectively reduce interference The lid should be soldered or sensibly clamped to ensure stable performance Receiver Option A 157 The FUNCube Dongle FCD using SpectraVue software SpectraVue has some useful options for collecting outputting and processing radio astronomy data The dongle has 96kHz bandwidth for 192kHz I Q sampling rate but with the software minimum Fast Fourier Transform FFT size of 2048 it requires a long observation time with a lot of averaging to achieve an acceptable sensitivity SpectraVue provides a u
70. o the weak signal and the difficulty in differentiating it from the background noise The presentation demonstrated how an interferometer reveals point sources as a fringe pattern overlaid on the galactic background Dr Morgan used two pairs of Yagi aerials separated by 30 metres representing 40 wavelengths at the observation frequency of 408 MHz at a fixed declination and allowing the Earth s rotation to sweep the aerials across the sky He presented a recording of 17 hours worth of transit Making 4 measurement of Virgo A data clearly showing the background emission from the galactic plane with the interferometer fringes of Output signal from the interferometer with 40 baseline Taurus A and then six hours later the fringes from Virgo A M87 see figure to the right Continuous signal record ever 17 hours Dr Morgan concluded by comparing simple amateur A veh designs with the large arrays of professional instruments such as ALMA LOFAR and the SKA A H significant problem for these telescopes is the huge d Pon demand for computing power to process the vast Meu NI amount of data created by multiple baselines LER eg ue Indeed the SKA is being designed on the assumption that future developments in computer Right Ascensia hrs design will provide the processing power needed for its full operation Astronomy at MegaMegaHertz To most people in the audience the Far Infra red FIR
71. om the sun Noah then described new projects starting at the school centred around the construction of a radio telescope to observe the 11 GHz region of the spectrum This will be built around a TV satellite dish and they have an ambitious observing programme including observations of the Sun and Moon as well as a raster scan mapping of geostationary satellites It is inspiring to see the progress the school has made over the last 12 months and hope we can look forward to an update from Noah next year with results from this project and perhaps an announcement of another new project Software Techniques for the amateur radio astronomer Matt Earnshaw has been looking at the current state of commonly used software for the recording and processing of information in the context of radio astronomy While there is a range of both open source and commercial applications they often have deficiencies for example data loss in recording and a lack of consistent data definition which makes it difficult to combine or compare data from different locations Posing the question Where to go next Matt started to outline the requirements for a new approach The definition of an agreed standard has to be the starting point it should have a common metadata description which is both flexible and extensible The recording of data should be lossless enabling future re processing of the raw data Making this happen could be difficult however Matt was
72. omy was well represented with several solar telescopes in use and some specialist telescope and camera equipment providing observations of Jupiter s cloud formations in mid afternoon Daylight is not an issue for radio astronomy and we were able to demonstrate a steady stream of meteor reflections during the run up to the peak of the Perseid shower which was due the following day The antenna was a simple 3 element Yagi cut for 143 MHz GRAVES operation and at approximately 5 metres height above ground level and with 20 metres of RG 58 coax connected to a FUNcube Dongle Pro Plus receiver Bletchley Park is also home to the RSGB s National Radio Centre which includes an Amateur Radio HF station so some interference was expected and a dual helical filter provided by Alan Melia was inserted immediately before the FCD receiver to provide an additional gt 50 dB attenuation below 120 MHz Either this was tremendously successful or the RSGB station was not in operation as we didn t encounter any problems on the day Left A portable 5 metre mast was used to carry the 3 element Yagi cut to receive meteor reflections of the GRAVES radar system The mast also supported one end of the simple dipole for receiving Jupiter emissions A second demonstration covered the reception of Jupiter emissions using a simple dipole antenna slung between the support for the meteor scatter Yagi and a second pole with both traditional short wave and FUNcube Dongle receivers o
73. on Latitude Longitude HeightAboveSeaLevel If you used the installer to set up Starbase then all of this information should already be present If not then use the Metadata Tab to import the Observatory metadata This will give a location on the equator and so if you select the Starmap Tab with these settings you will see that the sky appears quite different book Astronomical Algorithms by Jean Meeus a classic in its field have faithfully followed the details in the book but cannot guarantee that the generated ephemerides are error free This part of the software is particularly difficult to test because of the many variations of input data locations and times m Your feedback is much appreciated m Starscript By now you will have noticed the Commands Tab which contains several control buttons grouped into Modules Commands and Parameters All of the various functions of all of the instruments are controlled in this identical way The user interface metaphor is much like a programmable oscilloscope or signal generator the user selects the operation required and the values of any parameters and then executes the command Grouping the Commands into Modules simplifies the structure and makes it easier to remember where to find specific commands This hierarchical structure lends itself well to some kind of scripting or macro language which we hope to implement one day In th
74. onised by NTP gt lt DaoClassname gt org lmn fc frameworks starbase plugins observatory ui instruments impl clock dao NTPSynchronisedProxyClock DAO lt DaoClassname gt Later developments may include other DAOs such as a GPS synchronised source as discussed earlier Once you have learnt Java it is not too hard to write your own components for this system because everything is very modular and compartmentalised A new DAO to derive the source of Time from your own project is quite feasible Acknowledgements Starbase project has now been running for six or seven years and has accumulated an enthusiastic group of supporters developers and testers There s probably too many people to list them all but those with a continuing close involvement include John Cook David Farn Chris Green Mark Horn Andrew Lutley Alan Melia Laurence Newell Norman Pomfret Martin Richmond Hardy For further information offers of assistance or requests for new features please contact the team at starbase Qukraa com This project has also made extensive use of material from numerous other projects as open source software libraries design ideas development tools and so on Our grateful thanks to this huge body of people who in making their own dreams have also facilitated ours RAGazine Sep 13 Brief History of RAG The history of radio astronomy within the dates back to 1955 when Martin Ryle gave a le
75. onomy Association UKRAA 48 54 62 64 65 66 Coordinator s Remarks As with the rest of this newsletter this report is a venture into new territory so it is appropriate to begin with an explanation of the aims of both the publication and the column As the Coordinator for the Radio Astronomy Group my role is to keep the Group s membership informed about wider events and initiatives happening within the Association and of course to keep the BAA Council informed of what is happening within the Group In practice the first of these tasks is more about filtering and highlighting information that may be of particular interest to radio astronomers The BAA Journal appears more frequently than this newsletter and the BAA website and E bulletins are better for disseminating up to date news However there is a wider aspect in that the Group has many participants who are not members of the BAA This column thus provides a means of communicating the Association s activities to a wider audience of potential members The Group always encourages membership of the BAA as we believe it provides a good way to promote amateur radio astronomy in the UK through channels such as this Newsletter and the organisation of general meetings It has to be recognised that the large majority of BAA members are mostly concerned with visual astronomy at the moment anyway Very little radio astronomy RA material appears in the BAA Journal so th
76. orded as SIDs Again there were no X class flares and just a single M class Complications can arise when trying to allocate SIDs to their flares as several regions on the Sun can be active at the same time Fig 5 overleaf shows my recording from July 5 that RAGazine Sep 13 appears to show a single SID peaking at about 13 03UT The SWPC lists three flares occurring at this time as follows Start Peak End C2 8 11 15 13 00 13 30 C8 5 12 55 13 01 13 04 12 28 12 28 12 32 2013 July 5 23 AkHz _ hil A E s The first two are from the same active region while the third unclassified flare is from a different active region This is marked on the chart while the two X ray peaks marked are not listed at all The much stronger C8 5 flare will have caused the largest contribution to the SID although the C2 8 flare would normally Cause a good SID on its own so close to midday Magnetic A Bartels Diagram is the usual way to show magnetic activity The Solar rotation number is shown in the left hand column with 27 days per rotation Fig 6 is the Group s Bartels Diagram starting in 2010 January shown on the following two pages Coloured blocks indicate the level of magnetic activity recorded B C M and X indicate the flares recorded each day The Carrington rotation number is also shown With uncalibrated magnetometers in noisy domestic environments it is very difficult to be consistent
77. ped by Simon Dawes of Crayford Manor House Astronomical Society CMHAS Simon s page contains a good description of how his own CA script works and the information can be used to modify your own script to suit particular applications See http cmhas wikispaces com RadioMeteor RAGazine Sep 13 Periodic Actions During setting up and initial operation it is useful to be able to review all the events captured so that you can check whether the settings are capturing all the significant events You can also spot non meteor events such as satellite passes The Periodic Actions feature saves the waterfall screen every 5 minutes for later review To enable this function check the Active box in the top left hand corner of the Periodic Actions screen under the File tab in the main menu bar Remember that 120 such screens per day will eat into hard disk capacity The settings in the standard configuration file provide a known starting point for investigating meteor scatter Once you are familiar with the way that Spectrum Lab works you can start to modify these settings to look at particular areas of interest for instance to look at more of the detail in the reflections from the trail Spectrum Lab will update its configuration file each time it shuts down so it is always worth saving a copy of the original file in a separate folder so that you can get back to a known starting point if needed This new PiBow Timber model is a
78. purious points occur Again the receiver has not been frequency calibrated but the hydrogen line components are obvious and compare favourably to that collected by more complex RAGazine Sep 13 systems The ordinate is the measured result of taking the ratio of signal record to matched load input record The VCO feature can be removed by more receiver gain to better match the input noise signal to the dongle ADC dynamic range Figure 7 shows improved performance by using a third 20dB gain RF amplifier increasing the front end gain to 60dB leaving the dongle gain max at 42dB so that the overall gain exceeds 100dB Unfortunately this pushes the budget up by another 55 In Figure 7 using two 97sec rtlsdr bin files of antenna and load inputs and RAFFT exe averaging program and finally dividing the resulting text data the plots show red plot Galactic longitude 155 0 latitude typical hydrogen line plot black plot Galactic longitude 145 25 latitude cold region but slight bump at 1420 4MHz zero relative velocity is easily visible so checking the RTL dongle frequency calibration blue plot Galactic longitude 195 10 latitude but directed at the sun baseline shift shows sun temperature and also hydrogen line the antenna beamwidth is 26 so encompasses hydrogen line response at O deg galactic latitude A rough temperature calibration is marked with the conclusion that there is probably quite a lot of
79. r type of clock simply means writing a DAO to obtain data from a different system for example as shown in the diagram above from a GPS synchronised source The architecture below allows for any number of different types of clock but as far as the user s software is concerned it still calls getTime crm oleAatorm Clock NT PSynchronised Pro v lock ATP yia Internet ber rial Choice of Source of Time via DAO Selection So by now you will be asking How do select which source of Time to use With the answer comes warning that it may mean delving into new territories Since Starbase is a data driven application e it is configured entirely separately from the software itself it is necessary to edit a configuration file plain text The configuration is encoded into the formal structure of XML and is done this way to minimise the risk of errors and ambiguity So to choose the Time source we must specify the DAO to use for the Instrument described above and edit the ObservatoryClock instrument xml file to select one of the following two entries either lt SimplePlatformClockDAO just Uses the PC platform clock gt lt DaoClassname gt org lmn fc frameworks starbase plugins observatory ui instruments impl clock dao SimplePlatformClockDAO lt DaoClassname gt RAGazine Sep 13 lt NTPSynchronisedProxyClockDAO runs independently of the platform clock synchr
80. region of the electromagnetic spectrum is largely an unknown quantity but Dr Chris North Cardiff Univ and co presenter for The Sky at Night explained that the sky is as bright at these wavelengths as it is at the more familiar optical wavelengths For ground based observers the majority of the FIR spectrum is blocked as it is strongly absorbed by water vapour in the atmosphere There are a few holes which permit some observation but the majority of observatories are either on satellites such as the Herschel and Plank space telescopes or at high altitude such as the James Maxwell telescope on Hawaii and the ALMA array in the Atacama desert Dr North explained the sort of objects that emit in this part of the spectrum the physical processes involved and what we can learn by imaging at these wavelengths The radiation is generally emitted from regions of RAGazine Sep 13 gas and dust but at elevated temperatures 10 to 100 perhaps condensing to form proto stars or being compressed in star forming regions He presented recent observations of one of our closest neighbours at these wavelengths made by the ALMA telescope showing that the star Fomalhaut has a constrained ring of gas and dust at a diameter of approximately 100 AU leading to postulation that it may indicate the presence of shepherd planets with actions similar to some of the moons in the Saturnian ring system He went on to discuss other observations
81. run in the Command line The procedure for this is described below 1 2 3 Copy Command com from C WINDOWS system32 to your working folder directory placed on the Desktop Open Command com and check that it is initialised in your working directory Type doskey and press the keyboard Return key This allows the up down keys to be used to remember earlier commands for ease of editing and repeating To record data to bin files type on the command line rtl sdr exe capture1 bin f 1420e6 2048e3 42 n 200e6 which tunes to 1420MHz samples both and ADCs at 2 048MHz sets dongle gain at 42dB and records 200million and 200million Q samples interlaced in the output file The output file capture1 bin is stored in the current folder To perform and average 256 point FFT spectra type RAFFT exe capture1 bin capture1 txt 256 so the output capture1 txt file stored in the current directory can be input to Excel or any math cad program to compare pairs of load and antenna files to view hydrogen line spectrum Editor s note This article also appears in the Jul Aug 2013 issue of Radio Astronomy J of SARA RAGazine Sep 13 Novice Experiments with 1420MHz Hydrogen Line Receiver Components Martyn Gawthorpe G8FEK Basics Introduction Enthusiasts familiar with high sensitivity receiver systems used for terrestrial communications will seek low noise figures but with antenna
82. ry of Early Radio Astronomy Cosmic Noise by W T Sullivan Cambridge Univ Press 2009 A History of Earty Radio Astronomy 574 pp 140 US Woody Sullivan is a professor of both astronomy and history at the Univ of Washington Seattle and this comprehensive account of the early years of radio astronomy took him part time and finally full time for 2006 over 35 years to complete much longer than the historical range of developments chronicled This is a work of great scholarship with full annotations and referencing and also taking into account interviews around the world many of multiple long sessions with over 115 early workers in this field together with lab note books contempo rary correspondence and personal photographs The author s long preparation has been a labour of love and it shows This book is of fairly large format modest font size and is extremely well presented and profusely illustrated albeit not in colour The only negative thing can point out is that it is a tad expensive but nevertheless it s really great value managed earlier this year to buy an imperceptibly damaged copy at about 70 of the list price Woodruff Sullivan HI Scope There are 18 chapters as well as appendices containing more information on the interviews listings of bibliographies biographies and archive material sources radar development literature and most signifi cantly a 20 pp appendix which supplies a super
83. s directed at the horizon it soon becomes clear that 1 or 2dB noise figure amplifier is more than good enough and in some circumstances introduces severe problems Manmade noise power received in the antenna aperture particularly below 1GHz added to the natural ground noise of the earth and structures defines the noise floor in your receiver Lower noise figure amplifiers inevitably involve dynamic range compromises and your terrestrial receiver system potentially becomes less sensitive due to the blocking and or intermodulation impacts of out of channel transmitters However point a clean pattern antenna at the sky and different opportunities for low noise figures open up particularly above 1GHz 1 By clean pattern we mean an antenna exhibiting very low gain in all directions other than straight ahead In this way we reduce the noise power arriving at our receiver input from the earth s surface and from manmade sources and unlock the potential of a very low noise receiver preamplifier Using two different preamplifiers we demonstrate the impact of noise figure performance using cold sky to warm ground noise difference measurements At the heart of the experiments the cantenna preamplifiers and FUNcube dongle Our experiment uses a cantenna tuned to 1420MHz There are many references available on the web The one here was built by Kevin G3AAF 2 and uses coffee tins As you can see it s electrically quite simple just tin cans and a probe
84. se wall several metres away and repeated It s important not to just rest the open end of the cantenna on the ground since the antenna would be detuned and erroneous noise levels be observed The left plot is for the 0 95dB NF preamplifier the right plot the 0 45dB NF preamplifier The cold sky to warm ground for the 0 45dB NF amp is approximately 5 2dB and for the other amp is 3 7dB Observation 0 5dB lower NF at the preamplifier input results in 1 5dB increase in sensitivity RAGazine Sep 13 References 1 Galactic noise level references are available at www rfdesignuk com Appnotes htm 2 For more information on the 1420MHz cantenna Kevin G3AAF at kevin avery03 fsnet co uk 3 The preamplifiers are from RF Design at www rfdesignuk com 4 FUNcube Dongle information at www funcubedongle com 5 Spectravue is available from www moetronix com Did you know Plasticine This children s modelling clay never sets and makes a great sealant indoors and out In fact it is categorised in many wholesale suppliers under sealants and sold in large bags Maybe not as good as amalgamating tape but much easier to modify So use it to supplement or replace grommets and around RF and DC connectors and so on Does it really work The tip originally came from a very experienced radio amateur who has has been using it for many years Interestingly he used to be a very senior officer in submarines Lightnin
85. sea tierra reat Ls Lo 1 wiu eat ate deis record has been Parabolic Reflector _ Rot tree VLA Dip Fike Somat Pol BIN 20 W a HY ES y Es gm am Dips Tum Mere ag 5 ox 104 Had den qe i Ss jo ihr Panini Ua UANI ees Bev tee m I a 1 ivi 2 pud Efectos Aperta Baar Vim Fang Nin one Sun Ta TE Te B Par Trucs Powe si ng Macr rns Horne Con Stat aaah Ir By Daia E 1559 dedu E wan ter aver TE Grm EET enl Reap Daraa 101 003468 1223 Rx 37 2 K 0 52 dB i MEM x ma ge Peres Hob bcr Fader Es U Thus 53 177 Min ume Arjan Woo Umm gera Foo EN 52 36 8 ones ase la MH Lu twm ve E EMEN MEE miere 53 a ie Tab nr 8199 7 0 gt Eee Above Screen shot EMECalc showing use of Dual Mode feed top and Kumar Feed bottom RAGazine Sep 13 Results and feed placement When fitted to the telescope the new feed gave Sun to Cold Sky Y measurements as predicted In addition to radio astronomy my
86. seful spectrum display with facilities for FFT averaging In the radiometer equation the temperature sensitivity dT T 1 V nbt where the FFT bin bandwidth b 96kHz 2048 is 47Hz and the FFT data collection period t 2048 96kHz Averaging FFT bins for 100sec then v nbt 68 5 Note bt 1 for any single FFT bin for any number of FFT points and clock rate all the sensitivity benefit comes with the averaging In practice with reasonable observation times useful but noisy hydrogen line spectra can be obtained Figure 5 The figure shows four overlapping FFT 96kHz spectra covering the frequency range 1419 95 MHz to 1420 2MHz each covering 96kHz 1 1 d a r m P mm m g Figure 5 FUNCube dongle receiver spectra ee This dongle wasn t frequency calibrated and there was known interference from PC s close by Improved performance was noted when interfering sources were located screened or switched off Data shown is the ratio of the signal from the antenna to the signal noise measured when the input is switched to a reference load Ideally this removes the receiver gain response and allows temperature calibration this is demonstrated in the section Temperature Calibration below SpectraVue has the capability of outputting files of averaged FFT data and also raw IQ data in wav formatted files The dongle narrow bandwidth and the software minimum FFT size
87. sitions Planeta 10 ee Note Pat Feed Type version History vi3uMcem Help About Et Seaton iMi mac ortum os ea Mente s Vaga E 383 imm ul mme MOSB E Lll am somm MEN ERE CI ET lxi omui pr d cm r mA a om urx mrk ao E 77 Parabolic Reflector Hr E Pe m ima 10 ux c m 9 2 096 m meses Li Ute ANANI NAGE Rees eY SE SEN Mee a n B Tal a E mg o 9 a B zl bs Home Staton Y Factor Calc ewe ow Byte Tr Pura a Cau IRE 3E7E d al EEO watis 77 Gr idw 696 206 w EIRP Trk aa aquis Point Sauce Y Factor 0 791 dB fie TH 372 Las a Sp TKST 7648 Cantmarus A S Aperture Seuroe caicuiatoas PEE OA isa cM DCN weed for 1208 and stove a E Purges id i i ae apris Home Station at ab Dx Station nz App M Yagi Array iuiar Yarm i any Tx B Dx Station p 2313 aj um bisat ipara ag ange mpi Gar m XE 2 a rE MHz 2704798 SK 128 Hur iz 190 mm m 30mm 158 3 dim 07 dH 12 B5 ce 1 H a 10 50 dBd 1265 dili
88. strength a distinctive single peak is clear This represents the relative motion of the Earth to the clouds of neutral hydrogen in our local arm This technique was then applied to observations in the direction of Deneb in the constellation of Cygnus These showed a set of three peaks of diminishing amplitude representing three distinct masses of hydrogen moving at different relative velocities corresponding to the local Orion arm the Perseus arm and the outer most Cygnus arm below Brian continued these observations at different radial directions across the galactic plane to map the distribution and relative motion of the neutral hydrogen in our galaxy demonstrating the translation of radio observation to physical science Using the FUNcube Dongle and budget alternatives for hydrogen line reception At last year s meeting Tony Abbey was one of the presenters who introduced the FUNcube Dongle FCD for use in radio astronomy He started this year with a detailed evaluation of the new FCD Pro Plus which includes improvements enhancing its performance in some radio astronomy applications Tony then considered a number of alternative receivers which are available for as little as 10 compared with 152 for the new FCD Pro Plus These devices e g that shown below left can have lower performance and are much less sensitive than the FCD However radio astronomy systems often have a pre amplifier at the antenna which tends
89. t So it s like Jodrell then But that s huge Yes but l m just an amateur 4 anyway it looks as though the space weather is expected to be rough lomorrow Eh RAGazine Sep 13 Alc oho lt CAN cul U5 t 3 On nm 5f 2o dont F and deciVve Did you know High finance with your pension and ISAs EM Applications and other whizzy financial corporations use the VaR algorithm much these days to help their clients manage risk in portfolio management EM state that the EM algorithm is used in radio astronomy to clarify the objects underlying a mass of data and with its ability to handle data and shed light on unobservable variables it is well suited to pricing and managing the risk of investment portfolios And VaR remains at the heart of risk estimation for banks and asset managers It s all based on the original work of Stroyny and Wilding apparently Are you comforted by all this Hmm Remember it s all going to be different this time around again But to blame the radio astronomers Be very afraid RAGazine Sep 13 Advertisements RE lesion Weak signal tools for radio communications Noise generators with professional grade flatness 100kHz through 11GHz Calibrated noise sources low VSWR 10MHz through 12GHz Noise amp Gain Analyser ZVIHz through 1 8GHz I P 0 100kHz noise O P Low noise a
90. teers Anyone interested in joining the group should contact Gordon at gordon dennis koalapub co uk Please give an indication of your existing astronomy experience and indicate what interests you about this project You don t necessarily need radio astronomy experience as this is primarily a science project and any astronomical experience could be useful Editor s note the group is also looking for a great acronym l ve suggested one but let Gordon know your better ones And did you know The physicist Walter H Schottky did not invent the hot carrier diode that carries his name Rather he is responsible for one of the most crucial developments in audio and radio history the ribbon microphone But he did develop the underlying theories that relate to metal vacuum and most importantly metal semiconductor barriers and much else that is significant besides including the thermionic emission Schrot shot effect Of interest to radio astronomers and hams is that he seemingly may well have invented the super heterodyne receiver before Armstrong did and he certainly invented the screen grid tetrode Occasionally he gets confused with Shockley whose Nobel prize winning work inventing what became the BJT effectively spawned Silicon Valley and explosively so But unlike Schottky he was most irascible and courted increasing opprobrium through his later strident advocacy of eugenics RAGazine Sep 13 Low Cost H
91. the right is an arbitrary scale for power intensity 1 www funcubedongle com www moetronix com spectravue htm www gnuplot info RAGazine Sep 13 Degrees X Degrees Conclusion The project is one of several am working on all trying to enable useful scientific study using very basic cheap equipment that might be accessible to more people than otherwise may be the case do this to try and promote practical science and to show that you don t need to spend a large amount of money to get respectable results and have a lot of fun am trying to design all of my projects so that would be able to do them on the budget of my earnings from my first part time job working at a supermarket At HIS moment am working on Advancing my 12GHz telescope SID reception Monitoring the geomagnetic field VLF amp ELF reception Total power radio astronomy at 611 MHz Meteor reflections receiver Receiving the hydrogen line Many thanks for reading hope you found it interesting Stay tuned RAGazine Sep 13 Radio Astronomy Group at The National Museum of Computing August 11 2013 Paul Hyde A pleasant sunny day in the grounds of Bletchley Park found several RAG members supporting The National Museum of Computing s TNMOC Daytime Astronomy event The aim was to show just how much astronomy can be done at more sociable hours and without needing to pile on the thermal underwear Optical astron
92. trum to 12 kHz but dramatically reduces the loading on the host cpu 9 Set the waterfall display for horizontal scrolling at a rate that presents a new screen every 5 minutes and spanning a frequency range between 2 9 and 3 8 kHz It may be necessary to slightly modify these frequencies as each FCD receiver has a small individual frequency error determined by manufacturing variance The example used for this article registered frequencies as being 340 Hz higher than actual so the GRAVES transmissions appear at 3 340 kHz 4 Route the audio from the FCD through one of Spectrum Lab s amplifier blocks the gain of which is controlled by the slider on the right hand side of the screen The initial gain setting is very low to adjust this select the Components window and adjust the slider control N B If the resulting audio output level is still too low try adjusting the computer s internal gain settings Spectrum Lab Components Volume control L1 L5 L1 M T Y Y Y Input Degimode Spectrum Counter Monitor Monitor Detector peril ruthy ser 2 0 00000 Hz Lett Filter amplifier Menu Legend active passive Errore 380 Above Spectrum Lab Component Settings Spectrum Lab should now be able to monitoring general meteor activity Some fine adjustment of the waterfall sensitivity B and Contrast C settings will be needed to suit the Us
93. ts as a reference It is easier if these moments in time are always available to all instruments to avoid recalculation and perhaps a loss of synchronisation The ObservatoryClock therefore provides a common Time service to all instruments It is worth noting that the clock instrument you see in the rack on the left hand side in each of the Group tabs is exactly the same clock so if you stop one clock they all stop and SO These notes will probably end up as the document on the instrument s Help tab in advance of any proper Help information General User Firstly start the clock by clicking the small green button which appears on the clock s control panel in the rack of instruments Most users will probably be quite satisfied using the default setup for the clock which uses the host computer s hardware The time may or may not be accurately synchronised with some reference Time We ve called this the SimplePlatformClock RAGazine Sep 13 User views a Wall Clock Here the user is looking at the Time on a clock on the wall The control panel of the ObservatoryClock is set to show the time in this way Simple isn t it But sometimes things are not quite as they seem What other functions are available to the user in the Clock s interface 18 54 22 Ld uses ari Time System Clocks ELLA p Juan Se LI aes mE EROR L Due ee
94. ularly those associated with solar flares The unit was designed by m John Cook and uses a Honeywell magneto resistive IC as the sensor Controller The UKRAA Controller is designed to provide an interface between the Starbase observatory management program and radio astronomy instruments It also provides an autonomous logging facility so that several instruments can be observing at the same time without the need to keep a PC switched on UKRAA has several products under development at the moment including a switchable Signal Generator and a Calibrated Noise Source We are currently seeking to add some new faces to our team of volunteers and would welcome offers of assistance We have a variety of support tasks on which help is needed No particular knowledge of radio astronomy is required although most of the tasks require access to the internet and a reasonable level of IT expertise Please let us know e mail info ukraa co uk if you would like further details or if you think may might be able to help RAGazine Sep 13
95. undeterred and proposed an open crowd sourcing approach In this way a consensus leads to the standard and the open source community provides the development He invited all those interested in contributing to such an initiative to contact him directly Lunchtime demonstrations During the interval there was an array of demonstration equipment from group members including a fully steerable parabolic dish Trade and other stands exhibited magnetometers meteor scatter equipment and hydrogen line receivers providing an insight into some of the practical aspects of amateur radio astronomy SEE i i im Optimising the performance of parabolic 77 reflector antennas Peter Blair examined the factors in optimising parabolic dishes and their feed systems and went on to look at techniques for their construction A key objective is to maximise the gain for the desired signal source while simultaneously minimising the system noise temperature The of the dish depends on diameter and wavelength but it is also limited by the efficiency of the design Efficiency is maximised through the illumination of the dish and m minimising surface errors and losses There are three main components of system noise namely antenna noise receiver noise and sky noise The sky noise component is out of our control but the other two can be influenced by design For antenna noise there are four elements
96. will endlessly produce content for every single page in each future issue PLEASE think carefully each and every week about what interests you what you are developing and observing what interesting news items you have seen etc and write in with your snippets and or articles and your suggestions or requests We are primarily interested in encouraging the generation and dissemination of interesting material less in the polish of presentation within reason The RAGazine does not purport to be a learned or professional journal it is for amateurs involved in or interested in radio astronomy and geophysics am happy to work with you to help complete suitable material Articles on work in progress are also much welcomed am quite flexible over text and picture file formats but please remember that a single pdf file will rarely suffice on its own This first issue contains several consolidation items so the length is somewhat greater than for most future issues Note too that a single rather than multiple column layout has been adopted This is primarily an electronic publication and many readers find that for two or more columns the constant on screen scrolling is unwelcome Our simpler approach also speeds the editor s job We realise that our choice gives a somewhat less professional look and feel so we welcome feedback on this matter of compromise RAGazine Sep 13 We have an understanding with US based SARA Society o
97. ws an early oscilloscope CRT display with a stop watch in the right hand corner to supply the time stamping It s also sobering and sadly amusing to be reminded of the real shortage of funds that were the stuff of everyday frustrations by luminaries such as Lovell and Ryle difficulty justifying a subscription to Nature a crucial journal for RA at that time and the shenanigans in securing chart recorder paper from the USA for the Cavendish and Jodrell teams It is also good to see the few woman who could contribute in these early years properly recognised here including the UK radio amateur Nelly Corry and Jodrell s Mary Almond Style and profiting from WWII Do not think for one moment that this is a dry convoluted and mind numbing account Certainly Sullivan well conveys the confusion and false trails the practical technological problems that would trouble these early workers but its done in a masterful digestible style As it happens my late father was a navigator bomb aimer during WWII and used kit that Ryle Lovell and others developed so frenetically in so few years so was especially interested in this vignette which also serves nicely to give a flavour of this book Before better equipment could be built however Ryle and Vonberg devoted much of their first year to restocking the bare shelves of the Cavendish with everything from voltmeters and cable to giant antennas This could not be done with purchases as there was no mo
98. ws the number of Sudden lonospheric Disturbances recorded each month since the BAA Radio Astronomy Group was reformed in 2005 This was right at the end of solar cycle 23 when few flares were being detected as SIDs The period through 2008 and 2009 marked an extended minimum before cycle 24 activity began in early 2010 Since then there have been four distinct VLF flare activity 2005 13 EN uu M m X Relative sunspot number 160 Number of 8 1 05 recorded peaks in SID numbers with current activity being again fairly low The colour bars indicate the magnitude of the flare causing the SID The magnitude scale is logarithmic C being the smaller followed by M and X class full descrip tion of flare classification can be found at www britastro org radio flare html Rela tive sunspot numbers are courtesy of the BAA Solar Section and are smoothed with a 13 month weighting The 2013 peak occurred in April with 82 SIDs recorded May had 77 including the first X class flare of the year on the 13th This flare was recorded by all of the active observers Fig 2 to the right shows the X2 8 flare at the end of a busy day as recorded by John Wardle in Bridlington RAGazine Sep 13 BRIDLINGTON UE emu os C WT J ELE um vd p zt iF Ad Fa and i J at uli LEO CLINT P 15 TE UM LE 1 a
99. ydrogen Line Radio Telescope for 160 using the RTL SDR Peter East David Morgan has written two excellent articles on Measurement and Analysis of the Hydrogen Line and Experiments with a Software Defined Radio Telescope This was the inspiration to have a go to see what could be achieved with minimum expenditure Figure 1 shows the resulting schematic and Figure 2 the receiver implementation Total cost apart from the laptop is about 180 The RF switch isn t really necessary and drops the total cost to 160 A p 22 element Yagi 2x Minicircuit 1 ZX60 P162LN a Switch Antenna load comparison Interdigital filter Figure 1 Simple Radio Telescope Figure 2 Basic Hydrogen line receiver Antenna 10 The antenna constructed for ease of testing through a bedroom window comprised a 1 5m length of 2cm 1 hardwood with 1 6mm brazing rod elements screwed to the hardwood It was designed using P McMahon s YagiCAD and based on DL6WU20 file in the software Example Models list The CAD software allows the design to be re tuned to 1420MHz the impedance comes out close to 50ohms with RAGazine Sep 13 a good front to back ratio Beamwidth is 26deg and about 18dB Figure 3 shows the antenna with an inset detail of the construction Figure 3 Simple 22 element Yagi Switch 20 A single pole 2 way RF switch Figures 1 amp 2 provides a reference for comparing and calibrating th
100. z E Strach Phase switched interferometer 151 MHz Tapping Phase switched interferometer 408 MHZ Full power system 2800 MHz t Left John Smith with his home _ made dia parabolic antenna Sources www britastro org radio www ieeeghn org wiki index php First Hand Fifty years of R D 26 D in Engineering and Technological Education www itnsource com shotlist RTV 1963 04 1 7 BGY504300235 s reel Not to be confused with the professionals RAS which was also a little slow to embace radio astronomy earlier RAGazine Sep 13 http articles adsabs harvard edu cgi bin nph iarticle query bibcode 1998JBAA 108 29B amp db key AST amp page ind 0 amp plate select NO amp data type GIF amp type SCREEN IF amp classic YES www 408mhzsurvey org uk JRS Survey at 408MHz pdf www ukaranet org uk downloads index htm Editor s note It was Frank Hyde s Practical Electronics articles on the instruments that he built in and around his S Coast Martello tower that inspired me when at high school A school friend and I built two Kooman array based tube receivers and started to track the first US astronauts in the early days at VHF This reinforced my choice of electronics as a career But did not learn until recently that Frank Hyde had at around that time 1963 secured a grant from NASA to investigate with Florida State Univ the possible relationship between Jovian and solar emissions Confusi

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