MAP65 STATUS REPORT July 28, 2008 MAP65 is a computer program designed to be the "back end" of a semi-automated, wideband, polarization-matching receiver for JT65 signals. It works together with Linrad (by SM5BSZ) and suitable RF hardware -- ideally, hardware that provides two orthogonal polarizations on receive. MAP65 automatically finds all detectable JT65 signals in a 90 kHz passband, matches the linear polarization angle of each one, decodes the messages, and provides the operator with a "band map" showing callsigns, operating frequencies, polarization angles, and message contents over the past 20 minutes or so. The program runs under Windows or Linux. Its principal intended application is EME or "moonbounce" on the amateur VHF bands. MAP65 uses the JT65B protocol. The most important difference between MAP65 and WSJT running in JT65B mode is that WSJT receives a single 2-4 kHz bandwidth and decodes one signal at a time. MAP65 works with a dual-polarization or "xpol" system, accepting signals in two orthogonal polarizations each with 90 kHz bandwidth. MAP65 scans the whole received passband, automatically determining the frequency, drift rate, time offset, and polarization state of every detectable JT65 signal, and decoding each one. I have been using MAP65 for 144 MHz EME for slightly over a year. The program has given an excellent account of itself. It will surely continue to evolve, but with version 0.9 r1001 it is already stable and reasonably mature. MAP65 is a pleasure to use. It is very exciting to have the whole 144 MHz digital EME band available on one's computer screen simultaneously, including the contents of messages that are being sent. On an active weekend I commonly see 10-20 EME signals on the waterfall at any time -- and MAP65 decodes them all. When a new station turns up and calls CQ, I see his signal immediately and can respond right away. No advance knowledge, schedules or internet liaison is required. A screen shot of MAP65 (version 0.7, r474) has been posted at http://physics.princeton.edu/pulsar/K1JT/MAP65_5.JPG. The snapshot was taken after MAP65 had processed data recorded between 0745 and 0800 UTC on November 11, 2006, during the second weekend of the ARRL EME contest. (The minutes starting at 07:47, 07:49, 07:51, and 07:53 are absent from the recording because I was transmitting then, working WA8CLT on 144.131.) If you were on the moon at this time using JT65 on 2 meters, your signal is probably among those found and decoded by MAP65 for this screen shot. My antenna at that time was quite modest: a pair of 2.1 wavelength, cross-polarized yagis. To gain some operational understanding of MAP65, I suggest that you read the remainder of this status report with the screen dump in view. Be sure to expand it to full size or print a clean copy with full resolution, in "landscape" orientation; there is a lot of information present. The screen shot shows four MAP65 windows: 1. The main MAP65 window, at bottom left, is similar to the main WSJT window. It is used for conducting QSOs in nearly the same way as with WSJT. 2a. At top right is the Waterfall window with two separate panels. The upper panel gives the wideband spectral view, in this case extending from 144.075 to 144.171 MHz (the "144." part of the frequency scale is suppressed). I live in a densely populated region and the birdie situation is usually awful, as you can see: the continuous vertical lines are all birdies of one kind or another. The ones with messy sidebands at 144.091 and 144.140 are especially annoying. Nevertheless, you can see many EME signals in this display. You should be able to find DK5EW, EA3DXU, and W3SZ at 144.103, LX/PA3FPQ, IW4ARD, AA7A, and W0HP at 110, HB9Q and LZ1DP at 111, IK3MAC at 114, DL8EBW and UA9HK at 116, RA3AQ and DJ9CZ at 118, RK3WWF, I1ANP, SV8CS, and N5KDA at 123, K7MAC at 124, YO9FRJ and EB1DNK at 125, K6MYC and RN4AT at 126, KB8RQ, SP2JYR, and UA9SL at 127, AA1YN at 128, S52LM, WA8CLT, and F6HVK at 131, EA6VQ at 139, DH7FB at 140 -- yes, right in the middle of all that garbage! --- and DF2ZC at 152. There are more signals in there, too -- and MAP65 sniffs them out and decodes them. Nearly 50 callsigns are decoded in this 10-minute data segment, about which there is nothing special: it just represents a time that I remembered to turn on Linrad's recording feature during the contest, to save the raw data. 2b. The lower waterfall display gives a "zoomed" view around the operator's selected QSO frequency -- in this instance 144.128 MHz, where AA1YN is calling CQ. AA1YN is the signal near DF = 220. At DF = -660 Hz you can see the strong sync tone of KB8RQ, who was working a steady stream of stations on 144.127. During the displayed time interval he finishes a QSO with someone (you can see his shorthand RRR and 73 messages near the bottom, at 07:48 and 0750 UTC). Then he comes back to SP2JYR and works him; and finally at 0759 he is called by UA9SL. 3. The window labeled "Band Map", at top left, presents a list by frequency of all stations that MAP65 has decoded. The user can set a maximum "save time" for keeping a callsign in the map; after the specified number of minutes has elapsed, a callsign disappears from the map if it has not been decoded again. Stations decoded in the two most recent sequences are always displayed in red; progressively older decodings are indicated with yellow and then diminishing shades of gray. 4. At bottom right, the "Messages" window lists the results of all decoded transmissions over the specified time interval. Again, color codes are used to indicate aging. Each message is preceded by numbers giving the nominal frequency in kHz above the band edge (128 means 144.128, etc.), the additional frequency offset DF in Hz, the measured polarization angle in degrees, and the UTC. The decodings are sorted by frequency and then by UTC, and DF is used to group together all transmissions from the same station. Some interesting peculiarities can be seen in the Band Map and Messages windows. The DXpedition LX/PA3FPQ is working a pile-up on 144.110 and is using messages like "ARD FPQ RRR" (rather than the shorthand RRR without callsigns) to avoid any possible confusion over who is being worked. By scrolling back in window 4 (obviously you can't do this with the screen dump), you could discover that W0HP and AA7A are queuing up to work the guys in Luxembourg after they complete with IW4ARD. At 144.140 you can see that DH7FB is using an old version of WSJT. He is calling EA/DJ4UF, but the older version did not handle add-on DXCC prefixes like EA/ automatically. Therefore WSJT sent his message as plain text, and the last letter of his callsign (the 14th character in the message) was necessarily truncated. JT65 free-text messages are limited to 13 characters. Like WSJT, MAP65 does a "quick decode" at your specified QSO frequency, starting at about t=52 s in a reception interval. Then, during the next 20 s or so the program finds and decodes all of the JT65 signals discernible in the 90 kHz passband (or some designated portion thereof). MAP65 is robust and produces few garbage decodes, even in the presence of messy QRM. Once set up properly it finds, synchronizes, matches polarization, and decodes JT65 signals entirely on its own -- even amidst a jungle of birdies -- without operator intervention. In answer to some of the many queries I have received: 1. This particular screen shot was made on a Windows machine, but MAP65 runs equally well under Windows and Linux. WSJT runs on the FreeBSD and Macintosh platforms, as well, and I expect this will be true of MAP65 -- but it has not yet been tested as I do not have machines running those operating systems. 2. In principle the Linrad "front end" of the MAP65 wideband receiver can run on the same computer as MAP65, or on a different computer. At present, for a number of reasons I recommend using two computers on the same local area network. The "network" can be nothing more than an RJ45-style crossover cable. 3. MAP65 is memory hungry. The present version uses about 670 MB of RAM. Performance is acceptable on a 1.4 GHz machine with 1 GB of memory, but a faster machine would be better. Your monitor should have at least 1024 x 768 pixels, and more is better. The sound card on the MAP65 machine is used only for output of Tx audio, as all signal input comes in the form of ethernet packets. 4. The present version of MAP65 assumes that you have an xpol antenna with both polarizations simultaneously available on receive. You should have two tower-mounted preamps and separate Rx feedlines for each polarization. My system uses the WSE converters designed by SM5BSZ for use with Linrad. My Linrad computer uses a Delta-44 soundcard to sample a pair of I/Q channels (four analog signals in all) at 96 kHz. With other receiving hardware it would be acceptable to use "real" rather than "complex" sampling of two channels at 192 kHz. In the future I may provide a MAP65 option for single-polarization use, but a significant portion of the power of the Linrad-MAP65 combination would be lost in that case. It's hard to overstate the importance of having both polarizations available simultaneously when receiving EME signals on 144 MHz (and presumably also on 432 MHz), where the JT65 protocol really shines. 5. Like WSJT, MAP65 is an "Open Source" program. I hope and expect that others interested in this newly developing area of amateur radio experimentation will come forward and contribute to its development. Obviously, people with established skills in digital signal processing and computer programming will be very welcome as part of the development team. However, a qualification at least as important is real enthusiasm and a willingness to learn. I knew essentially nothing about digital communication techniques when I started the WSJT project six years ago. For me, as I think for all of us, learning is a major part of the fun. 6. If you have ideas for the future development of MAP65, but do not feel that you can contribute directly to the programming effort, please email them to k1jt at arrl dot net. 7. If you have a suitable station configuration and would like to participate in tests of newly released versions of MAP65, please send me email. -- 73, Joe, K1JT