MSRX V4 User Guide
Contents
1. repetition OHO DI HG PDOHCY 26 26 1 3 231 1 0020 A BAYH 3 3 98 1 0030 BF a RRE 62N 1 0 20 1 0046 v OHOJ4AJ5HG PDOHCVZ 6 26 0 0 repetition 26 on0 703506 PD OHCYZ26 1 6 77 1 0044 5 0 0 84 1 0081 hs R Lauw Figure 1 The Graphical User Interface of MSRX and a decoded result Decoded frames of PSK2k are more confident than any single character of FSK441 Decoded text therefore is completely displayed in bold letters in magenta color see figure 2 My Locator UTC Clock To Call Pattern 1 Pattern 2 PSK Reporter DJSHG RRR APESE PEEP EED a EPE N E PE ont ah ATE TI UER AE 4 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 9 10 11 dB 99 2 5 0 2 oO df rate decoded 67 0 9990 T 8 H T L GW4WND de DJI5SHG OdB 1 0002 JO53IM 270 500W 18dB Figure 2 DJSHG replies to a call of GW4WND in the PSK2k contest mode recorded by GW4WND This frame sends the callsigns a signal report consisting of the SNR here 0dB and the number of decoded frames here only 1 a QSO number 0002 the Maidenhead locator JO53IM the QTF 270 the tx power 500 W and the antenna gain 18 dB PSK2k signals usually do not lead to decodes by the FSK441 receiver and FSK441 signals cannot be decoded by the PSK2k receiver Both modes can be used simultaneously on the same frequency 2 2 2 Repeated Information FSK441 transmits a short sequence of characters many times repeated for periods of 30 seconds Oft2. DJ5HG de GM6 XB R3dB I097AQ 115 8 106 DISHG de GM6 VXB R3dB I097AQ 115 ODnOorROOAwWON oO NW Figure 4 Result of a simulation with the above simulation parameters Some pings are very weak Nevertheless the error correction of PSK2k leads to very confident complete results while FSK441 never decodes any useful result at such low signal levels See figure 5 for comparison with WSJT The simulated wavefile of this example is available at www dj5hg de digitalmodes sim_examp1le_1 wav WSJT 9 02 by K1JT File Setup View Mode Decode Save Band Help mp le _1 sim_example_1 1 2 DF Freq kHz 26 207 N2ZS7 6 16 246 4 26 100 26 187 To radio Lookup Ss 4 I Zap DJSHG id da DJSHG 26 26 Tol 400 J RxST DJSHG R26 R26 RRRR RRRR DJSHG Rot a E DJSHG Dsec 0 0 Gen Msgs Z fca DJSHG TxFirst TxST 1 0000 0 9999 Freeze DF 0 Rx noise 7 dB T R Period 30s Figure 5 The decodings of WSJT for the wavefile sim_example_1 wav are comparable to those of MSRX in figure 4 But there is a severe difference All callsigns of the WSJT decode are not confident because none of them occurs at least twice In contrast the MSRX decode says HBO6RJP is more confident than HB6RJX OZ7FRN is confident by repetition and RN2ZR even is fully decoded from three different pings The PSK2k pings at 6 5 above the m of mple_1 16 8 below the H of Help are visible but extremely wea
3. could generate an FSK441 transmission of SM9UVW R26 ZAOXY SM9UVW R26 R26 An ideal transmission with fixed information and zero offset and 1 0 as samplerate factor is generated by 1 6 0 1 CQ DJ5HG It will lead to signals of about 6 dB on average 7 4 Simulation of PSK2k Messages Generation of PSK2k transmissions is a little bit more complex because PSK2k uses several different message types and because the callsigns are clearly separated from reports and other information callsign in the following table means a text which is explicitely given in quotes and which satisfies the syntax rules of amateur callsigns As in the FSK441 specification this also can be a random callsign specified by or pattern and pattern2 are the actual textsettings of the pattern entries of MSRX for MyCall and ToCall Be aware that the simulator generates messages sent at the other end to your call That is the reason for the interchange of MyCall and ToCall The text of both patterns must satisfy the syntax rules of amateur callsigns MSRX needs permission to store the generated wavefiles If permission is denied start MSRX with administrator rights The message types are message type l OMmANANIDMNABRWN 10 11 12 13 14 15 16 17 QST message of max 10 characters CQ de callsign QRZ de callsign CQ de callsign with QTF and period pattern de pattern2 pattern de pattern2 pattern de pattern2 pattern de pattern2 patte
4. 25 16000 32000 44100 48000 6 3 Frequency Deviation The maximum allowed frequency deviation of the received FSK441 signal is 360 Hz 6 4 Coherent FSK Demodulation The FSK441 receiver reconstructs the carrierwave of the received signal The demodulation is done by taking the real value of the complex signal instead of the absolute value of it This leads to a gain of 3 dB Unfortunately the carrier reconstruction is somewhat errorprone when the signal amplitude changes rapidly as in meteorscatter pings The real gain of coherent demodulation in meteorscatter therefore is less than 3 dB 6 5 FSK441 Decoder The FSK441 decoder of MSRX uses a method similar to a Viterbi decoder for the character synchronization It minimizes the probability of synchronization errors which for example in WSJT can change a sequence of RRRRRR into XXXXXXor Additionally such a sequence only uses the FSK frequencies 1 and 3 If the frequency offset is more than 220 Hz it inevitably leeds to a decode O00000 FSK frequencies 2 and 4 This problem only can be avoided at the transmitting end by inserting blanks RRR RRR RRR 7 Simulation 7 1 General A click on the simulation button starts the generation of a simulated signal which is stored in the actual folder of wavefiles to decode The filename is sim_YYMMDD_hhmmss wav where YY MM DD hh mm ss are replaced by the year month day hour minute second resp The simulation parameters are re
5. Gladstone N1DQ runs the PSK Reporter system which collects reception reports and displays them according to different options MSRX can automatically send datagrams via the internet to the PSK Reporter with the callsigns decoded by the PSK2k decoder The user must explicitely allow this by setting PSK Reporter to ON in the menu bar You also should enter the actual dial frequency in Hz into the edit field below the PSK Reporter button The background of the edit field is gray if the automatic report is set OFF and light green otherwise The reporter goes to OFF if you choose any File Option other than every period MSRX sends the following information via the internet 1 The receiver information example your callsign DJS5HG your locator JO53IM your actual decoding software MSRX V4 0 2 The reception reports frequency 144360000 mode PSK2k UTC of decode 25 Jun 2014 21 37 29 decoded callsign GW4WND SNR 3 MSRX sends this information with the datagram protocol This is a one way communication To get the information back you have to open https pskreporter info pskmap html or something else
6. MSRX V4 User Guide by Klaus von der Heide DJSHG 1 The Purpose of the Program MSRxX is a receiver for two digital modes used in meteor scatter communication FSK441 and PSK2k Since it is a receiver only it is designed to work in parallel to WSJT or to analyse earlier records of WSJT or PSK2k The interpretation of the decoded output of MSRX is considerably easier than that of WSJT 2 The Display of MSRX 2 1 The Signal Display Similar to WSJT MSRX displays a signal over the time of the actual record But it is not the amplitude of the received signal it is the output of the synchronization units which detect the 441 Baud of FSK441 black and the two frame headers of PSK2k magenta for general messages and green for QSO messages 2 2 The Decoded Text 2 2 1 Confidence Information The FSK441 decoder of MSRX generates a confidence value for each decoded character This confidence is used to control the visibility of the printed letter Garbage can easily differentiated from useful received information see figure 1 for an example 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 2 2 28 29 dB df rate decoded 1 9 242 4 1 232 1 0049 B OK2PWY 26 26 SHO DISHG 26 OK Pwy 26 2 6 OHO DI5 G R4 O repetition GHOYDISHE 26 ox2PWY 26 26 0 6 79 1 0057 Sy DL 8 CPIT9H 9 repetition ac Svar 0 3 78 1 0037 RR DL YBF BRR 3 3 2 1 0052 G DOHCY 26 26 OHO DISHG ay 26 26 OHO YOISHG PDOHCY 26 2 8 J5 1F QH 8 8H BDU
7. ad from a textfile which is selected via a standard fileselection dialog 7 2 General Specification Format Like reality you cannot influence the simulated meteorscatter channel But you can define several transmissions with different information and different mode Each line of the textfile defines such an individual information to be sent The line is not formatted It starts with 4 numbers separated by blanks The meanings of the first 4 numbers are 1 1 means FSK441 2 means PSK2k 2 mean SNR of pings or bursts for this information 3 frequency offset in Hz of this transmission if this entry is absolutely larger than 500 Hz then a random offset is generated with meanvalue 0 and standarddeviation 120 Hz best is to use the value inf in this case 4 samplerate factor if this entry is less than 0 99 or larger than 1 01 then a random factor is generated with meanvalue 1 and standard deviation 0 005 best is to use the value 0 in this case 7 3 Simulation of FSK441 Messages In case of FSK441 the 4 numbers are followed by the text to be sent This text must be set in quotes The text may only use the FSK441 alphabet ABCDEFGHIJKLMNOPQRSTUVWWXYZ 0123456789 and additionally the characters and These both characters will be replaced by random callsigns Ifa occurs more than once in the same text of the same line it will be the same callsign in the transmission Therefore a line 1 3 120 1 003 R26 R26 R26
8. can enter what you want See figure 1 for an example with the three patterns OHO DI5HG RRR and 73 The clearly formatted display of PSK2k output does not need such accentuating 2 2 4 Ping Data The following data of the actually decoded ping or burst precede the decoded text T the starting time of the decoded text in seconds start of record 0 0 W the length of the ping in milliseconds FSK441 only dB the average SNR of the ping df the carrier frequency deviation from the nominal value in Hz rate the samplerate factor FSK441 only determined if the signal duration is long enough 2 2 5 Decodes of PSK2k Decodes of the PSK2k receiver are printed in magenta color The confidence of all PSK2k output is very high Therefore it is completely printed in bold letters PSK2k generally decodes full information frames In contrast to the PSK2k program MSRX dispays all decoded frames even if the same is repeated many times 3 The Program Control The User Interface of MSRX is very simple There is no menu Control is done by only two buttons Clicking the File button steps the action of the other button through the following options These actions are started by a mouseclick on that button open open a wavefile and decode it open next open the next wavefile in the same folder next in time not in alphabetic order open remaining open remaining wavefiles ordered by time of recording every period look every period for the latest wavefil
9. e and decode it simulation generate a simulation wavefile and decode it see Chapter 7 exit program exit Additionally there are three text entries for special patterns Their content is arbitrary But PSK2k does only decode calls to your callsign if the entry for My Call really is your callsign and QSO information R report RRR 73 etc only is decoded if you have entered the other callsign into the second pattern To Call On some systems the OpenGL renderer does not display the graphic text correctly A doubleclick somewhere on a free space within the signaldisplay toggles the renderer between OpenGL and zbuffer 4 The History Window The main decoder window shown in figure 1 only shows the result of the last period The results of previous periods are transferred to a history window Here also one period at a time is displayed But there is a simple bar of buttons for navigation through the history of the last 16 periods MSRX History SV2JL_040811_095300 previous Bate hai han Rath Senta cant Wile bith he Niet A Sort Paton di 5 6 7 8 9 10 11 12 18 14 16 16 17 18 19 20 21 22 23 24 26 26 27 28 T Ww dB df rate decoded 13 5 116 4 0 263 0 996 w JL CQ S 2J Figure 3 The history window with four navigation buttons 5 The Output File The displayed output of the FSK441 decoder is a graphic It is stored in RichTextFormat rtf in the file you have to select when MSRX is started It is recommend
10. ed to transform this file after program exit into an other format by a usual editor like OpenOffice all pdf html odt by DJ5HG in the internet are generated with OpenOffice The odt and pdf files need very much less space than the automatically generated rtf files The examples in chapter 2 2 2 are taken from an rtf output Here another example generated from a record by GW4WND which shows decodes of FSK441 and PSK2k in the same period on the same QRG The FSK441 receiver does not see the PSK2k ping at 20 5 and the PSK2k receiver does not notice the FSK441 signal from 24 9 to 26 1 09 26 24 9 96 0 8 163 0 992 P X 25 1 323 2 4 168 0 994 HX S 2H D I X SP2H D I01 H P2HP D Wc X3S 2 PM J U repetition SP2HPD IW1LCHX 25 7 97 1 5 175 0 988 wc 26 1 150 1 5 154 1 003 v P Vv 20 4 5 3 3 GW4WND de DJ5HG TNX 73 20 6 2 3 3 GW4WND de DJ5HG TNX 73 6 Characteristics of MSRX 6 1 Ping Detection The ping detection of both the FSK441 receiver and the PSK2k receiver are based on the synchronization units This may lead to a very different signal display compared to WSJT Especially the PSK2k receiver does not see FSK441 signals or QRM 6 2 Samplerate Detection The synchronization unit of the FSK441 receiver of MSRX automatically adapts to samplerate differences between transmitter and receiver of up to 3 The evaluated ratefactor is added to the pingdata see figure 1 MSRX supports the standard samplerates 8000 110
11. en pings and especially bursts are long enough to show this repetition MSRX detects the repetition even at very low signal level After a decode of the complete sequence MSRX adds the repetitions of the detected symbols and decodes this averaged signal Sometimes weak bursts can be resolved this way and of course weak tropo signals and airplane scatter The decoded text of the repetition is printed in red color It also is controlled by the confidence values The following result of three consecutive minutes is from very weak airplane scatter 24 7 818 0 6 144 Vv DL9M B V H vV S F L D D L vV L repetition SV DLOMS DL7FF 4 5 463 0 1 222 Z L C L D 9 F S 9 F repetition SV DL9MS DL7F 9 6 260 1 8 125 D 7FF V D Fe sv DL 7 D IMS repetition DL7FF SV DL9MS 10 2 124 4 0 125 L FS MD 9 SD7F repetition SV DLOMS D 7FF 10 6 82 4 7 121 35R D 92 3D 7FN V D 10 8 114 3 9 127 L DOSV L S DL7FF SV DE9MS D repetition DL7FF SV DL9MS A second example is a sequence of three weak pings or a long faint burst over a large distance 2250 km 14 9 154 0 2 179 Q N CQ N BJ N repetition CQ RNOBN 17 5 306 1 5 183D 0 999 6 r N repetition 18 2 162 2 2 179 repetition 2 2 3 Accentuating Speeialipattenns MSRxX can accentuate special textpatterns in the decoded text by green background There are three small edit fields to enter three patterns usually your own callsign RRR and 73 but these fields are not specialized So you
12. k Nevertheless they communicate all information of the contestformat as seen in figure 4 Neither WSJT tries to decode PSK2k pings nor the PSK2k receiver of MSRX is irritated by FSK441 signals Both modes FSK441 and PSK2k therefore can be run on the same frequency 8 Installation If you do not already have installed the MCR download the Matlab Compiler Runtime and install it Then download MSRX unpack it and store the program msrx exe at a location of your choice After a first start of the program it usually takes a relatively long time to reassemble it on your computer Later starts are faster For a first try open an FSK441 record of WSJT Then click the File button to select open next and click this button to open the next file s To decode actual receptions you must start the monitor of WSJT or set Auto ON Set Save to Save all Then start MSRX and open a record in the actual record folder of WSJT Later choose every period in the File menu of MSRX Then 8 seconds after the end of every period MSRX looks for the newest record and decodes it with the FSK441 decoder first and then with the PSK2k decoder On some systems the OpenGL renderer does not render the decoded text correctly or even does not display any decoded text On a double click in a free area within the signaldisplay the renderer of both figures is toggled between OpenGL and zbuffer This hopefully solves your graphic problem 9 PSK Reporter Philip
13. rn de pattern2 pattern de pattern2 pattern de pattern2 pattern de pattern2 pattern de pattern2 pattern de pattern2 pattern de pattern2 pattern de pattern2 pattern de pattern2 0dB 3dB 6dB ROdB R3dB R6dB RRR TNX 73 still not specified still not specified still not specified message given by max 10 characters The textline in the simulation parameter file starts with the same 4 parameters as a FSK441 line but the first parameter has the value 2 These 4 values are followed by the number of the message type The messages 5 13 are fully specified by these 5 numbers In the remaining cases some information has to be appended message type 1 message types 2 3 message types 4 message type 17 a text in quotes which specifies the message sent as a QST a text in quotes which specifies the callsign a is allowed a number which specifies the QTF in degrees and a text in quotes which specifies the callsign also a is allowed a text in quotes which specifies the private message Here three examples for the generation of PSK2k signals 2 0 O 1 2 2 5 O 1 4 120 DJ5HG 2 3 87 0 998 10 7 5 The PSK2k Contest Format generates a CQ with the callsign DJSHG generates a CQ with a random callsign and QTF 120 generates an R3dB message with the callsigns specified by the MSRX pattern entries The PSK2k contest format messages are generated if you add the following information to
14. the lines of message types 6 11 QSO number QTF in degrees output power in Watts antenna gain in dB Maidenhead locator in quotes A random locator is generated by Example 2 3 inf 1 002 8 137 215 500 15 J053IM generates a message sending a 6dB report a QSO number 137 a QTF 215 a power of 500 W an antenna gain of 15 dB and the locator JOS3IM 7 6 Example of a Simulation Text File 1 3 112 1 003 cQ 1 0 inf O 26 26 26 2 3 87 0 996 2 2 0 inf 1 10 1231 115 250 18 1097AQ The result of a simulation with this parameter file may be generated and decoded like figure 4 It shows very obviously the difference between FSK441 and PSK2k UTC Clock To Call Pattern 1 Pattern 2 2 GM6VXB 73 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 3 dB df rate decoded 1 8 252 1 0096 50n tO repetition 219 0 9955 Nosy 26 HB RIx RN2ZR 9 221 0 9904 N ZR 26 26 H Z 0 211 1 0024 ARH N2WR 2F 16 9 322 1 0055 PFEUH C EN 2 106 1 0065 Q 8 Q Z27FRN CQ O02 repetition CQ OZ FRN 222 0 9899 UGV 6 6 H GRIP RN2ZR 26 LA 222 0 9922 0 U 7 CO o 0 8 3 6 4 0 Q Qo 109 DI5HG de GM6 XB R3dB 1 1231 I1097AQ 115 3 106 DISHG de GM6 VXB R3dB 1 1231 I097AQ 115 8 106 DISHG de GM6 VXB R3dB 1 1231 I097AQ 115 Jo 103 CQ de ESILO 2 94 CQ de ESILO 5 207 DJS5SHG de GM6YXB R3dB I097AQ 115 oO 105 DISHG de GM6 YXB R3dB IO97AQ 115 9 105
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