THE LF NOTEBOOK #48 - The LOWDOWN, March 1997 The Mailbag, News and Comments About LF Radio, Etc. John H. Davis, Box 367, Warm Springs, GA 31830 - E-mail - longwave@mindspring.com -World Wide Web http://users.aol.com/lwcanews/ Faith an' begorrah, this has been an incredible month for correspondence! Our pot of snail-mail and e-mail gold runneth over, and no wee leprechauns have granted us extra pages. So, let's get straight to the news, and I (almost) unconditionally promise any surplus of letters will make it into next month's column. Thanks, and keep up the great work! Congratulations to Max Carter on receiving the H. John Clements award. It's a splendid acknowledgement of Max's work on the hobby's behalf. BPSK Updates There has been a veritable gold rush of BPSK news this month. The new COHERENT. Bill de Carle announced version 5.6 of his popular program in February, with some new features to make the system easier to use, especially on HF. (This was updated to Ver. 6 soon after. - JHD) Bill says it was found easier to stabilize Tx-Rx operating frequencies than to mess around trying to get rigs to tune in 1-Hz steps, "so it will be taken for granted that whatever band you operate on, your radios will be kept within plus/minus one (1) Hz or so by external means." "1. We are now concentrating on BPSK. The other modes (CCW, PSK, PSKL) have been discontinued and will no longer be supported. In over a year, I have seen zero interest in the PSK/PSKL modes and CCW is obsolete." "2. All timing for signaling is now derived from a single source, namely the 1.8432 Mhz crystal oscillator which is located on the Sigma- Delta board." It is no longer necessary to adjust the computer's timing in any way. "One negative consequence of this move is that you must have a Sigma-Delta board connected and powered up even if you only want to transmit data." There have been improvements in the display, and several other operational areas. One big difference is support for a wider of transmission speeds. Version 5.6 can send 200 bps (5 milliseconds per bit), to 3.33 bps (300 ms/bit); while version 5.7 extends that to 1000 ms/bit. The faster rates have proven their merit on HF, where rapid phase errors caused by shifts in the ionosphere disrupt longer bit intervals unmercifully. At 1750 meters, where propagation is inherently more stable, slower speeds are beneficial in overcoming noise. While PSKL is not supported in the new versions, a similar error tolerant (ET) mode is included. The software is at http://w3.ietc.ca/home/bill/bbs.htm . You may want to read Bill's full announcement of differences. It's available on the Longwave Home Page or Longwave BBS. Beacon ID generation is not included in the new version. It should instead be implemented by an EPROM or RAM keyer, such as the VE2IQ version previously published. (Anyone desiring to experiment with the earlier version of COHERENT can still find it on the Longwave Home Page or the Longwave BBS.) BPSK on 80 Meters has quite literally spanned the continent since January. On occasion, K0LR in Minnesota reports "nearly solid copy on both VE2IQ and WB6RIJ, without ever having to correct the startbit phase during a transmission. Even taking into account the fact that conditions were very good between here and Quebec last night, the performance of BPSK at MS50 and MS25 was impressive. I cranked the power setting on the IC-706 down to L, supposedly around 5 watts, and then turned down the audio input until the forward power reading on the MFJ meter was 1 watt. Bill also turned his power way down and we had essentially solid copy at both ends." Lyle later added, "I've been having fun participating in the 80 meter BPSK tests. Being sort of in the middle, I can usually get solid copy on WB6RIJ, K7RR and VE2IQ. We've settled in on a 40-baud transmission rate (MS25 mode, or 25 ms/bit), which still gives very low error rates and is faster than I can type. When conditions are bad, we invoke Bill de Carle's error tolerant ET software option, which catches and corrects almost all of the bit errors." Cliff Buttschardt describes MS25 mode thus: "We have reached the point where we can not type fast enough to keep up with the outgoing data and THAT is a most practical limit!!" The path between K7RR and VE2IQ on 3591 kHz (the current home of these skeds) is not always the greatest, but it does work. On one night, "DeCarle and I were on MS25 with reasonable sucess. We ID-ed in CW at the end. The CW was totally unreadable but the BPSK MS25 was about 50 percent copy!" *BPSK on LF. HDO is now using MS1000. Cliff reports, "I changed the ID time such that one letter per ten seconds is sucessfully printed using version 5.7 just downloaded. Do not lose patience when invoking SYNC on version 5.7! It will take a couple of minutes before you can obtain any meaningful letters (HDO), but they will eventually be there. There is no space between them; i.e., HDOHDOHDOHDO, each letter at ten second intervals." Results have been very encouraging at 187.65 KHz, with Lyle able to copy it in Minnesota again this winter, despite the HDO ground system disruptions we mentioned a couple of months ago. "After the conclusion of the 80M QSO I tuned to 187.650 to try for HDO. By about 0600 UTC, with the frame grabber set for a run length of 4 and 15-sample averaging, I was able to sync on a string that got as close as "HDN" a couple of times. At that point I turned on the TRACE mode and went to bed. At 1015 UTC I came down to check on the progress. There was nothing intelligible on the screen then, but the trace file showed that HDO had come through for at least a few repetitions of the ID cycle; probably somewhere between 1 and 2 AM. I tuned around the LowFER band and heard only ground-wave signals from SAM and RM. At that time of night (around 0430 CST) when band conditions are reasonably good, I would expect to hear at least one of the following CW beacons: TH, OK, TEXAS, YHO or KRY. None of them were detectable, so conditions were not optimum." Lyle included the trace file, which is on the LW BBS and Home Page. He adds, "I'm glad I didn't have to stay up all night watching one character per second." "For those (like me) who don't want to run their beacons exclusively on BPSK, I've come up with an add-on circuit for the VE2IQ identifier that will alternate the ID format between CCW and BPSK. The add-on circuit uses only two ICs and a few discrete components. While transmitting BPSK, the signal sounds like a constant carrier, similar to the long dash that many LowFERs include in their identifiers as a tuning aid. It's only when the signal is fairly strong that you can hear the slight warble of the BPSK modulation. LEK will probably go on a one-minute CCW, one-minute BPSK ID cycle soon. Another likely "guinea pig" for the BPSK/CCW tests will be KA0TUP's STLMO beacon on MF." *And, BPSK Overseas... Paul, PA0OCD (Diemen, Netherlands), posted a message on the Longwave Home Page's new message area. "I was looking for articles for VLF and came across ur fb website..... Here in Holland we do not have permisson for long wave yet, but we expect soon to be allowed on the 136-143 khz part with about 1 watt erp !!, and till now no restrictions on antennas." "With G3PLX and G0TJZ we have experimented on 40, 80 and 160 mtrs with slowbpsk. This is not the bpsk used with the coherent program from VE2IQ. The slowbpsk runs on an TMS320C50 DSP processor (will run soon also on an dsp56002evm) and is 31.25 baud. It can be used for 7 bits Ascii, but also with varilength coding. This varilength coding uses lesser bits for more commonly used characters, like the Huffman coding used by Pactor." We will be looking into some of the techniques in future articles. Beacon Bits Great with salads, soups, and winter DX too. One common factor you may notice here and in the Mailbag is how many good catches this month came about as the result of persistence...or, at least, having the receiver on the right frequency during that rare momentary lull in the QRN! - Dick Pearce, N1XKH, sent Lyle Koehler a reception report and audio tape recording of MedFER MIN as received in Brattleboro, Vermont! He also heard MedFER STLMO. Congratulations to Dick, Lyle, and Henry Hampel! - The informal Eastern LowFER net has had a great deal of difficulty coping with QRM from an AM group that has taken up residence two kHz up from the traditional 1983 kHz frequency. Lately, the LowFERs have been using 1961.5 instead, generally quieter in most areas. - David Jones (d.jones160@genie.com) heard NR, JDH, YD, and RED on an early-February monitoring excursion in West Georgia.. - William E. Bowers (okbill@brightok.net) finally copied LEK on February 12, after "two years and hundreds of hours of trying...at 7:00PM, the noise was unusually low and LEK drifted in through the noise. I have been working on LEK and BA for many hours this year, and now I can concentrate on BA." - Bob Hoffswell reports MedFER beacon JN is ready to go to its new home at John Horton's place in Mahomet, IL, but hasn't gone yet because its mast is still frozen in the ground! It continues on the air at 50 mW input, around 1641 kHz. - Your columnist's MedFER SEA hasn't been getting out well at all this season, thanks mainly to some landscaping work...which seems to have been abandoned by the parties responsible! If they ever finish, I'll try to restore the ground system. Also, I hope to experiment on 1684 kHz in late March/early April. The second frequency will parallel 1638.4 and will eventually replace it. Help Wanted Though it's hard to believe right now, spring is mere weeks away. That means summer lies ahead, too, with the usual drop-off in correspondence. There's normally plenty to fill this column well into May. But at some point, things do quiet down, and when that happens, it's great for Bill to have an ample supply of articles on hand. It's a good thing even at this time of year, just for the sake of variety. A relatively new member recently expressed concern about the general content of the publication since he started receiving it in October. I pointed out that this is a result of the seasonal nature of LF DX. But he's right in hoping for a mix of articles on antennas, interesting circuits, and so on. You may be just the person to write some of them! If you do, I hope you'll also consider making the article available to be published on the World Wide Web. There's yet another area where volunteers are most welcome, and that is checking in to the LF Home Page message area from time to time, and answering some of the questions you find there. (Thanks go out to Lyle Koehler and Pierre Thomson for pitching in to help this month, and to the visitors who had interesting comments to add to the discussions.) The Mailbag for March -Brice Anderson (BA, W9PNE; Lancaster, IL) says, "I used to like winter as there was so little QRN. HAW!" This year, Brice's QTH has seen S9 LF static levels in the daytime, and on MF, "you have to grit your teeth to hear signals through the QRN." Add numerous nights of temperatures below zero, and it's easy to lose one's fascination with winter. In general, Brice observes, MedFER reception hasn't been very dependable. Even ABC, a regular in previous years, is weak and only comes in every few days; while MIN, another regular, is more consistent but still weak (on Feb. 11, copy was RST 559 for a while, however). The best signal on MF is from STLMO, but with QSB. RGQ was 329-449 some evenings in January; CSA and VA have come through at times; and PX is weak and often not audible. SEA hasn't been heard this winter. Fortunately, LowFERs have been coming in much better, and Brice has managed several QSOs this season. BOB and BA had QSOs on December 15 and 16, at noon and 4:15 PM respectively. This made Illinois Brice's 15th state for an LF QSO! He and XJ had QSOs on Christmas with 579 signals at each end. Their traditional New Year's QSO was delayed by weather until January 5. Other regular reception has included YHO and TFQ. However, the last few weeks finally yielded stations Brice has been hunting for a long time. JDH came in "clear as a bell" during a lull in static, and OK showed up another night. He has been trying for TEXAS for a long while, too, but as of this writing has only acquired one or two letters of the ID at a time. Brice encountered complications from his eye surgery, slowing his recovery for a time, but reports he is improving steadily now. Those problems, plus generally lousy weather, made it difficult to do beacon maintenance. An apparent intruder in the back yard broke the ground system loose, resulting in almost no signal being radiated for perhaps two weeks, until the break was discovered in the middle of February. -Lyle Koehler (LEK, MIN, K0LR; Aitkin, MN; k0lr@emily.net) hears TEXAS, OK, TH, KRY, YHO, SAM, and RM on LF; and only STLMO on MF. "I still plan to complete the LF analyzer article mentioned last month, but kind of lost momentum when both Mouser and Circuit Specialists discontinued the dual-gang 266-pF variable capacitor I was planning to use. (This is the same part that's called out in the "universal" preamp design.) Dan's Small Parts has a nice 365 pF air variable that could be substituted. Unfortunately his supply is limited, and he doesn't know if he can get more. On the bright side, Dan's latest on-line catalog (http://www.fix.net/dans.html) now lists the MVAM108 varicap, which gives you a voltage-controlled 15 to 500 pF capacitor in a package the size of a plastic transistor. I've redesigned the LF analyzer circuit to eliminate the variable capacitor completely and will eventually get the article finished." On an unusual note, "Our two guinea fowl are competing for the title of World's Dumbest Bird. The other day it was quite warm outside (above 20 degrees F) and the barnyard critters were out enjoying the sunshine until the neighbor's dog chased the guineas into a tree. 'Turbo', the smart one, decided that one night of 10 degrees below zero was enough, but 'Charger' stayed up there another whole day. Kind of like sitting up all night listening to static crashes." -Mike Hardester (2Lakota@coastalnet.com (Mike & Caroline Hardester) checks in this month with the unfortunate news that "my R-70 is just about dead, so no DX here in some time, or in the forseeable future, unless I find a place that will work on it." "I received a cassette from Gary Jackson in Sacramento, CA, who sends me tapes of UNID CW loggings. Often they're the fish net type, but he had an interesting one I wanted to check with you about. His logging was on 11/25 at 1330 UTC on both 1690.9 and 1691.6 (I'm presuming nominal is actually 1691). The signal on the tape is weak, but I was able to tell it 1) wasn't a fish net buoy, 2) it was a repeating ID, and 3) the letters "I S" were sent together. I noted this a couple of times -- also, a possible "E" before the "IS," with maybe a 2 second pause. ( . .. ... ) "I checked past LOWDOWN issues with MEDFER listings, but the closest to the frequency was STLMO on 1691...somehow, I don't think so, hi! Any ideas on this? Checked my utility DX books, but nothing noted there. I'll say this about Gary, he's never at a loss for coming up with intriguing logs!" -Perry Crabill (W3HQX; pcrabill@visuallink.com; Winchester, VA) has a tip that may prove valuable to any number of folks before winter finally ends. "My 100-ft antenna came down some time ago, and it was not convenient to put in a new antenna support. The 30-ft antenna I was able to erect was OK for SW, but not very effective for BCB or LW DX. As an experiment, I unrolled my 100-ft extension cord on the ground in the back yard and used it for an antenna. It worked so well that I replaced it with a 120-foot piece of #10 insulated wire, and it worked even better." "Being covered with 6 inches of snow over the weekend hasn't made any difference in its performance. It seems to pick up less manmade noise, and is somewhat directional." -Tim Brannon (KF5CQ; Dallas, TX; 76546.1311@compuserve.com) writes, "I was deeply saddened to hear of the passing of Ken Cornell. I was given the 3rd edition of his Scrapbook series in 1977 when I was 14 years old, and it was the practical experience of building his circuits that taught me much of what I know about radio and basic electronics. When I had a question or a problem with a circuit, I wrote to Ken and I could always count on getting a helpful letter in reply, even though I was just some kid. It was Ken's encouragment that inspired me to read and learn more, and ultimately helped me get my Amateur radio license. For many of us he truly embodied the 'Elmer' spirit. He will be greatly missed." -Rob Gill (G8DSU; robjgill@aol.com) expresses his reaction: "I was deeply saddened to hear of the passing of Ken Cornell, W2IMB. His articles in the Lowdown and his Scrapbooks remain a source of inspiration and a testament to someone who prefered to "have a go" and actually try out ideas and see where they led. One of the old school who will be sadly missed." -From Mike Staines (Mike@nh.ultranet.com): "Sorry to read of Ken's passing. We all owe a lot to him." -From Jerry Green (K4UBR; k4ubr@worldnet.att.net): "It is with a heavy heart that I say Farewell Ken. The LowFERs have lost a truly great man. His passing has left a vacuum in our ranks that can never be filled." -Robert Laney (RL, WB7PZU; Herndon, VA) remarks, "I was very saddened to learn of the death of Ken Cornell. His Scrapbooks were a real contribution to the hobby. He will be missed." Robert saw my comments about the disappearance of Telstar 401 last month, and shortly thereafter read an article in the February 4, 1997, EOS, the publication of the American Geophysical Union, titled, "Did Space Weather Knock Out Telstar, Seismic Network?" The previous issue of EOS had an item titled, "Geomagnetic Storm Forecasts and the Power Industry." He may be able to make some of that information available to us for future reference. He also reports, "Thanks to suggestions from Lyle Koehler, RL now has more than double the antenna current that it had previously. Lyle sent an e-mail recently asking about some of my current measurements that I reported in the Mailbag. I made a number of additional measurements and we compared notes. A significant upshot of our correspondence was that I wound a new loading coil with #16 stranded copper wire on a 5-gallon plastic bucket and replaced the old coil." "The antenna current increased from 46 mA to 96 mA. The 96 mA reading is still much lower than I would like, but it sure is an improvement. Additional experiments and improvements are planned." -John Reed (jtreed@iamerica.net) reports on his winter activities. "On the Lowfer end, I finally managed to pull TEXAS out of the noise. This has been helped a lot by a new synchronous blanker I built. I can get TEXAS in the evenings at times, which is impossible without the blanker. I find my best reception is with the large ferrite loop built by Bill Bowers, sync noise blanker (usually) and CEI R1401. It is not possible to use my HF-1000 with the ferrite loop because of digital noise. I've also had some luck with an Eddystone 958/3 with its 150 Hz filter, but it doesn't seem to be as sensitive as the R1401. Also, the mechanical frequency dial on that set takes some time to get aligned exactly when using such a sharp filter." "This has been a poor season for Medfers. My only catches are STLMO, and that comes only in short pieces, and a beacon on 1675 that IDs as B320." "I've been testing several receivers and antennas with STLMO....the W-J HF-1000, Eddystone (mentioned above) and a solid state mil surplus Sylvania R1414/URR. This last set is a real sleeper. I was lucky enough to find one along with a complete set of spare plug-in circuit cards from a second de-milled set. This set uses four tuned circuits before the mixer with special tuning, known as Cohn filters, in each circuit. It also has an analog HF oscillator which can be locked at 100 Hz points, so no phase noise. The IF filters are large crystal units with excellent shape factors. The sharpest one is 100 Hz. Frequency readout is by a built in counter and nixie tubes and is accurate to 100 Hz. I built my own RF card to take the place of the one that was there, making the set more immune to IMD, and more sensitive. This circuit is courtesy of Dallas Lankford via an article in DX News." "The Sylvania set blew the others away. With the 100 Hz filter, I don't hear anything until the signal is tuned in. It's just dead quiet without a signal. On the other sets, there is always a lot of ringing from the filter edges due to noise that make it hard to tell if there's a signal there or not. The HF-1000 is a sensitive set, but noise generated by the sharp filter edges can obscure the signal, especially with narrow filter settings. I'm ready for the Medfers now, I guess all I need are some sunspots." Then, on February 7: "This morning I heard MIN clearly between lightning crashes. I also heard something where 0KVL should be, but couldn't get an ID. These were both heard best with the Eddystone. I wish I could figure out the right combination of things that make a good receiver for weak signals in noise. The HF-1000 has been a consistent third place in my Medfer tests. I haven't used the Eddystone that much, and with its Wadley triple mix tuning scheme, it takes a while to figure out how to get the most out of it." -Doug Faunt, Jr (N6TQS; faunt@netcom.com) mentions, "Joe Carr has a very simple VLF converter and preamp in the Ham Radio column of the March 97 Popular Electronics. It's basically missing coil construction details, but otherwise looks OK." -William Ashlock (WA; Andover, MA; ashlocks@mdc.net) is curious whether there are any LowFER enthusiasts in the Boston area. His beacon is known to get out at least that far, but he is puzzled by an absence of reception reports. Anyone? -A request from Don Davis (don.l.davis@trw.com) for ideas on V7AL7, an unidentified signal with carrier at 410 and CW at 410.4, that comes and goes over a span of days, IDing in rapid Morse. He also has some interesting thoughts on PYD that he will share with us next time. Footnotes. In April, look for still more of your letters...some of the feature material we've been hinting at in recent months...and our annual visit from Mr. Answer Guy, the man who knows many things and tells even more. Til then, 73. - - - ARTICLE CORRECTION - By Lyle Koehler: A correction to the diagram for the 10-Hz crystal-controlled frequency reference in the February LOWDOWN. I didn't show the ground connection to pin 8 of the 74HC4060. That's what happens when you do the original schematic entry in a program that doesn't show the power and ground connections on the symbols for the parts, because it's assumed that everybody knows what they are. -- Lyle (The corrected version of the diagram appears in the Longwave Home Page File Library, as part of the complete article.)