May 2000 QST

the software, PSK31 tuning required practice.You had to learn to recognize the sightand sound of your target signal. With theweak warbling of PSK31, that wasn’t alwayseasy to do. And if your radio didn’t tune in1-Hz increments, the receiving task becameeven more difficult.Nick Fedoseev, UT2UZ, and Skip Teller,KH6TY, designed a solution and called itDigiPan. The “pan” in DigiPan stands for“panoramic”—a complete departure fromthe way most PSK31 programs work. WithDigiPan the idea is to eliminate tedioustuning by detecting and displaying not justone signal, but entire groups of signals.If you are operating your transceiver inSSB without using narrow IF or audio-frequencyfiltering, the bandwidth of the receiveaudio that you’re dumping to yoursound card is about 2000 to 3000 Hz. Witha bandwidth of only about 31 Hz, a lot ofPSK31 signals can squeeze into that spectrum.DigiPan acts like an audio spectrumanalyzer, sweeping through the receivedaudio from 100 to 3000 Hz and showingyou the results in a large waterfall displaythat continuously scrolls from top to bottom.What you see on your monitor are verticallines of various colors that indicateevery signal that DigiPan can detect. Brightyellow lines represent strong signals whileblue lines indicate weaker signals.The beauty of DigiPan is that you donot have to tune your radio to monitor anyof the signals you see in the waterfall. Yousimply move your mouse cursor to the signalof your choice and click. A black diamondappears on the trace and DigiPanbegins displaying text. You can hop fromone signal to another in a heartbeat merelyby clicking your mouse! If you discoversomeone calling CQ and you want to answer,click on the transmit button and awayyou go—no radio adjustments necessary.(And like the original PSK31 software,DigiPan automatically corrects for frequencydrift.)Even I can Master DigiPanMost of the PSK31 signals on 20 metersare clustered around 14.070 MHz, so I justpark my rig in the vicinity and boot upDigiPan. I can opt to display the audio frequencieson the DigiPan waterfall, or I canenter the frequency displayed on my radio’sVFO and DigiPan will indicate correspondingRF frequencies.One remarkable aspect of DigiPan isthat it allows you to see (and often copy)PSK31 signals that you cannot otherwisehear. It is not at all uncommon to see severalstrong signals (the audible ones) interspersedwith wispy blue ghosts of veryweak “silent” signals. I’ve clicked on a fewof these ghosts and have been rewardedwith text (not error free, but good enough44 May 2000to understand what is being discussed).Using DigiPan reminds me of the sonaroperators in the movie The Hunt for RedOctober. There is an eerie excitement infinding one of those ghostly traces and mutteringto yourself, “Hmmm...what do wehave here? An enemy submarine rigged forsilent running? A distant pod of killerwhales? Or Charlie in Sacramento running5 W to his attic dipole?”DigiPan is, in my opinion, one of themost important developments in the briefhistory of PSK31. It makes this excitingmode more “user friendly” and accessibleto a larger audience and a larger assortmentof radios (the ability to tune in 1-Hz stepsisn’t a requirement for DigiPan). And Ihaven’t even mentioned DigiPan’s otherfeatures such as a type-head buffer, loggingfunctions, macros and much more. You candownload DigiPan on the Web at http://members.home.com/hteller/digipan/.Note that you need a 486-100 PC or fasterrunning Windows 95 or 98.PSK31 on the AirAs I’ve already mentioned, 14.070 MHz(+/– 2 kHz) seems to be the hot hangout forPSK31. Activity is gradually spreading toother bands, too. When 10 meters is open listenfor warbles around 28.120 MHz. PSK31operators also haunt 10.140 MHz on occasion.Last winter I heard some PSK31 actionclustered around 3.580 and 3.610 MHz.It’s fair to say that PSK31 signals nowoutnumber Baudot RTTY for casual QSOs,but RTTY is still the king of contests. EvenThere is plenty of DX on PSK31! 5N0ZKDhas been active on several bands.so, the PSK31 contests sponsored by theTroy Amateur Radio Association (TARA)and the Chautauqua County Contest Club(CCCC) have attracted a surprising amountof activity. Look for more of these to popup in “Contest Corral.”RTTY is still dominant in the digital DXworld, but that picture is changing rapidly.A number of DXpeditions have usedPSK31 and more have announced their intentionto be “warbling” from exotic locationsthis year.Has anyone worked 100 DXCC countrieson PSK31? I’ve heard of a few allegedclaims passed along the grapevine, but nothingverified—yet. The PSK31 DX is outthere. Even with my half-hearted attemptsat chasing DX I’ve managed to net about 30countries. Some of my catches have included5N0ZKD, TF3VS and 4Z5AO.PSK31 activities have not been confinedto the HF bands. Andy Bachler, N9AB, hastried PSK31 moonbounce experiments withlimited success. (Unfortunately the phasedistortion wreaks havoc with the PSK31signal.) Others have established experimentalPSK31 beacons on 6 meters, 2 metersand 70 cm. Some hams are even usingPSK31 on 2-meter FM as a kind of educationaltool to inspire their local brethren toexpand their horizons.The FutureI don’t think it is a coincidence that manynew PSK31 users are running low power,often with indoor antennas. Since PSK31 hassuch excellent weak-signal performance,hams who’ve been off the air because of antennarestrictions or RFI problems (or both!)are now finding a new way to enjoy thehobby once again. It’s common to read:“Running 20 W to an indoor dipole…”Amateurs who enjoy low-power QRPoperating for the sake of QRP itself are alsofinding excitement in PSK31. Although itis certainly feasible to operate QRP phone,the tradition has been to use CW for greatestefficiency. Now PSK31 offers a newQRP mode that rivals CW’s performance.Hams are buying used Pentium laptops(with sound capability) and taking them tothe great outdoors to run PSK31 with QRPSSB rigs. My guess is that you’ll hear morethan a few PSK31 signals next month duringField Day.PSK31 was in the right place at the righttime. Amateur Radio was in need of ajumpstart in 1999, something to bringpeople back on the air and help restore thelong-lost sense of wonder. Because the majorityof amateurs already owned computerswith sound cards, their “risk” and investmentin PSK31 was essentially zero. Allthey had to do was download the softwareand fashion a couple of cables. If they triedPSK31 and didn’t like it, little was lost.