THE LF NOTEBOOK (From August 1995 LWCA LOWDOWN) The Mailbag, News and Comments About LF Radio Etc. John H. Davis, Box 367, Warm Springs, GA 31830 -E-mail: johnhdavis@aol.com -Fax/Answering Machine: (706) 672-0964 -Longwave/Part 15 BBS: 706/672-0360 It's August...I think. Now, I realize we're sometimes a little behind other parts of the country on some things. But it looks like the first of August. It sure FEELS like the first of August. But we still haven't had the usual degree of summer correspondence drought for this column. Way to go! Not only do we have stuff to get on with, but it's interesting stuff. F'rinstance... * Coherent CW & BPSK Efforts Forge Ahead Events appear to be converging rapidly toward making advanced modes available to experimenters on a broad scale. Few things are quite as thrilling as hearing a real DX catch with one's own ears, as the ID faintly drifts in above the background. But for all the thrill, and despite all the challenge, there are only a relative handful of us in this hobby, scattered out over a vast area. That doesn't offer many opportunities for most would-be LowFER DXers inside their own region of the country, nor many chances for LowFERs using legal power to communicate with each other across several states. Yes, it can be done. It has been done. But there aren't that many chances. At some point, what stands as a challenge to one person becomes an obstacle to another. It has long been the hope of many LF enthusiasts to have access to a practical, long range digital transmission technique. Several exist that make very good use of information theory, extracting the utmost from every milliwatt. Coherent CW, Binary Phase Shift Keying, and various types of digital signal processing have been explored and applied by some of our more technically proficient members. Though effective, these techniques have involved more custom circuit construction than non-hardcore enthusiasts were willing to attempt. Practical access to these techniques clearly depends on the availability of kits (see recent BPSK Bits articles by Max Carter), but the economics of making printed circuit boards for a few score hobbyists, maximum, are pretty poor. Therefore, according to word reaching us in the past several weeks, Max and John West have been broadening their scope to reach a wider interest group, hoping to publish construction articles in general circulation amateur radio and electronics magazines. At this writing, the effort to talk JDR Microdevices into a kit appears not have borne fruit (watch for word from Max about this, if it hasn't already reached print before this column), but Dave Curry is now involved in the project as well. Cliff Buttschardt (C) writes that the efforts of Max, John, and Dave are well underway, "with a few of us helping where we can. One way that this effort can be aided is for a beacon to be placed in Central California with a good enough signal to act as a generator for the state." A later letter from Cliff adds: "This is going to be a great project when finished. We want to contact other experimenters to contribute. We are interested in DOERS, not talkers, where the goal is to communicate using weak signal methods." John West acknowledges: "I've been getting a lot of help from the St. Louis area and Southern California CCW and BPSK groups in the effort to make Max's designs available in a convenient and inexpensive form.... Things move slowly, but we're almost ready with it." John has also been involved with the software side of the project, fixing a bug in the COHERENT program that leaves the floppy drive running after the program has loaded. He says "it's a pretty simple fix," and invites users of COHERENT who want information on it to contact him. The address and phone number are with his letter in the Mailbag section. In addition, John has a goal of establishing daily LF BPSK contact with Max over the 150 mile path between them, despite summer QRN. Free labor, courtesy of his teenage nephew, may enable him to finish a half- wave helical antenna that shows promise of working well. As noted by Ed Phillips (IZJ) last time, Cliff confirms C has been placed in coherent CW service, with 30 seconds of 100 millisecond on-off dots followed by the message DE CUESTA TECHNOLOGY CCW 73 AR, repeating each minute. The 166.66--- kHz frequency was abandoned because of inter- ference from unknown sources, possibly industrial equipment using 1 MHz divided by six somewhere along the way. Even BPSK couldn't cope. However, on 187.650, results are good. Cliff reports: "The site is better than ever. It has been heard in San Diego with a good audio filter using ordinary means. The PCW program* has been used to lock on all over California. This has been found to be the best means of getting used to CCW operation--especially the use of 30 seconds of dots to be sure that the receiver is tuned properly." Bill Lake (WB6IRJ, Santa Barbara) and Cliff have been having CCW QSOs as well, showing off the method's utility in the ham bands. They meet on 7055 kHz at 1900 Pacific and 3605 kHz at 2000 Pacific. "The 40 meter schedule rarely results in a Santa Barbara-Morro Bay QSO due to skip, but it allows enquiries from the East to be answered. Both the newer PCW program and the de Carle programs have been used with success." (It is my understanding Bill uses a rubidium standard at his end.) Bill and Cliff have been working with G3IRM, transmitting CCW on 7035 each Thursday at 0500 UTC. On June 22, Cliff heard "a very weak series of dots, suggesting that Europe might have been there!" [*The PCW program is the one featured on the Longwave BBS in last month's column. It's a European variation on the VE2IQ COHERENT software that was uploaded to us by Bill Lake. The BBS is back in service as you read this; or I'll be glad to copy it onto your blank floppy with self-addressed, stamped mailer. Remember, it is shareware, so if you end up using it, you need to send its author a registration fee. Details are in the program.] *The Periodical Shelf Noise is a good thing??? Apparently it can be, when the phenomenon of stochastic resonance is applied. The August Scientific American contains an article entitled "The Benefits of Background Noise," by Frank Moss and Kurt Wiesenfeld. "Noise often creates confusion," the authors note. "Engineers have long sought means to minimize such interference. But surprisingly enough, during the past decade researchers have found that background noise is sometimes useful. Indeed, many physical systems, ranging from electronic circuits to nerve cells, actually work better amid random noise." (However, the same issue contains news suggesting that the seemingly random noise of the brain's cortex may actually be exquisitely timed.) They report on a theory that suggests a relatively insignificant periodic event (i.e., the 100,000 year wobble of the earth's orbit), much smaller than random "noise" (the normal annual variations in solar irradiation of the earth's surface), can be amplified by the effects of the random signal to produce a much larger result than it could achieve on its own (in this case, the Ice Ages). While this is still a hypothesis, quite a bit of work has now been done to demonstrate the phenomenon in electrical circuits, ring lasers, and bioelectric systems. (In fact, one of the hypothesized methods by which AC magnetic fields might have biological effects is thought to be by way of stochastic resonance, although the authors don't address this.) Physicists are looking at the possibility of SR affecting quantum tunneling. Appended to the article is a bibliography of half a dozen relatively available articles that should further illuminate the subject. Whistlers and other LF stuff populate Joseph J. Carr's "Open Channel" column in the July Nuts & Volts Magazine. A good historical background leads off the text, with descriptions of natural radio sounds, mention of Project INSPIRE, a whistler receiver design, notes on red sprites and blue jets, and a humongous bibliography that might be worth the price of the issue by itself. Also potentially useful is "Frequency Standards," by Corby Dawson. If you've ever wondered how rubidium and cesium standards work, this is a good article at a basic level. More red sprite discussion can be found on page 11 of the July, 1995, Geotimes, published by the American Geophysical Institute. According to this brief news item, "in a single night, a large storm system may emit several hundred sprites." There are several thoeries being investigated as to the origin of red sprites, including one that associates them with "positively charged ground strikes, which make up about 10 percent of lightning and are many times more powerful than the common, negatively charged lightning." (Well. That's a modest consolation, knowing that while I'm cringing in terror in our control room as sparks fly from wall outlets despite many kilobucks of surge protection and there's no power because the fuses have disintegrated on the 14 kV line outside, there's a good chance the storm overhead is producing red sprites and maybe whistlers for someone to catch.) Followup on power line fields. While not strictly periodicals, I did want to mention two things in connection with last month's ruminations on AC fields and the cancer debate. The Frontline program transcripts are said to be available by calling (303) 831-9000. And the American Physical Society background paper is now available on the Longwave BBS as BACKGROU.TXT or BACKGROU.ZIP, whichever may be most useful to you. *On To The Mailbag... - Rick Wright (R, KA5YWH; Durant, OK. E-mail: wrightj@marcie.sosu.edu) sent a message that arrived as last month's column was already winging its way to Pennsylvania, but it contains some very good news. "The morning of June 12, 1995 found us well behind a cool front, in clear air, and the QRN level was down. I went out to the quiet site with my 12 ft whip antenna and regenerative preamplifier feeding into my Sony ICF 2002 receiver. At about 200 Hz bandwidth it was no problem to read Bill Bowers' OK beacon at 189.9 kHz - He's transmitting a good signal! As Mike Mideke once pointed out, June mornings can be surprisingly good, and I agree with him. Nice to find Bill's signal on the air. Now I have OK and TEXAS." (At the end of the note was Rick's name with the call letters appended thus: "KA5YWH and the R-beacon," which struck me as being a great name for an Alternative Rock band. I've got the recording setup if anyone has the instruments and inclination. Sadly, only one thing stands between your columnist and a promising musical career...a tragic and complete lack of talent. But I do recognize a good name when I see one!) - Bob Laney (Herndon, VA) sent in the Geotimes news item mentioned above. He reports there isn't much LowFER activity right now. "I check the bands only on the weekends. But I think about my new LowFER antenna to be erected this fall while I mow grass, paint walls, hang wallpaper, spread mulch, and go to work." - John D. West (29 Highway 52 #27, Longmont, CO 80504; 303-652-0247) has some profound thoughts on the subject of an LF ham band. Because of his involvement with equipment development, he might stand to gain more from an amateur allocation at 1750 meters, but he doesn't support it. He has prepared an open letter on the subject that I feel eloquently expresses the attraction of the hobby as it now stands, which may appear in this issue or the next. Whatever your views on an LF ham band, this letter is well worth reading. John also has a suggestion on a topic that has occupied us before. When using a remote receiving antenna, there can be a problem with noise coupled between the power line ground and the remote ground, manifesting itself on top of the received signal. One way around this is an RF isolation transformer. Or, the signal could be relayed by radio. But J ohn has a simpler way that's available off the shelf. "I use a small isolated DC-to-DC power supply module to power the antenna preamp. I picked up a bunch of them surplus and use their +/- 5 volt outputs in series for the antenna amp. I use one to power my MAX800 and another to make my PC run on 12 volts. They're very handy. If anyone needs one, I have lots, cheap, $9 each." - Cliff Buttschardt (950 Pacific St., Morro Bay, CA 93442) alerts us to another impending noise problem on LF. "The noise generated by the 'high efficiency' fluorescent lamps wipe out all low frequency reception, even that of WWV on 60 kHz....HF lamps are oscillators directly connected to power lines. It would seem that such gross interference could be stopped by inclusion of ferrite chokes and bypasses. When TV sets first used direct connect power supplies, the problem was severe, but the television manufacturers responded to the problem. It now appears the same pressure has to be brought to the lamp manufacturers." - More good news from the West this month as LF mainstay Jim Ericson (EK, EK-3 formerly of Sunnyvale, CA) surfaced with some news from his new home near the Canadian border in upper Washington State. "It's been a year since we moved from the chaos of California Hi-Tech into Glacier, Washington, (pop. 98!) which is about 33 miles east of Bellingham. One would think that with all that time, and with 11 acres to play with that I'd be all set up and back on the air. The task of building a new home here and getting settled in a new community has severely limited my experimental radio efforts. "I have also had a couple of limiting bouts with arthritis and pneumonia, and in April I undertook a 12-step program to deal with the reality of my alcoholism. Things are going extremely well, and I feel better than I have in many years. I expect to have my HF ham station on line by the end of summer, and at least some plan formulated to get the EK beacon back on the air. Unfortunately, much of my longwave equipment is still in temporary storage back in California, and it may be Fall before I can get it up here. I hope to have more to report soon. In the meantime I can be reached on email (jderic@pacificrim.net), or by regular mail at POB 2001, Maple Falls, WA 98266." It is really great to hear from Jim again, and we wish him much continued success all the way around. - Quick FOR SALE Notes: Member Glenn Swiderski (19 Willa Drive, Buffalo, WY 82834; 307-684-5496) has two ICOM R71-A receivers with 12 volt hookups and FL32 CW filters in both. He's asking $475 each plus shipping. He also has a Sony 2010, new, in its box, for $325. - Lyle Koehler (LEK, MIN, K0LR; Aitkin, MN) hasn't let summer stop his LF and MF activities: "On July 1st I went down to Blooming Prairie, MN (no, I'm not making that up and yes, the school teams are still called the Blossoms) for my 45-year high school class reunion. The daytime QRN was low enough so I could hear BK (about 140 miles) and LEK (about 180 miles) on my portable receiver with the 30-inch loop. At home, I'm hearing BK, SAM, ART and SL when QRN permits. 0KVL is sometimes readable on MF but not on LF. MIN (MF) and LEK are still in continuous operation except during thunderstorms. I've only had to replace the final in the LEK transmitter once so far this summer." That's mighty good reception for summer, and pretty remarkable about the transmitter final. As for SL, that's a temporary beacon Sam Eastey operates intermittently from his lake home, a few miles from Lyle's QTH, on 186.225. Sam has managed to keep his regular beacon, SAM, on the air to provide a signal source, despite continual threat of lightning damage. Lyle has been conducting some interesting antenna experiments. "While visiting (son) Bruce's lake cabin on Father's Day, we tried using a loop antenna at the end of his dock to get as far away as possible from the power-line noise that has been wiping out his LowFER reception recently. An antenna above the dock would be in the way, so we tried sticking my 30-inch portable loop down into the water. The windings are enclosed in a hoop of 3/4-inch plastic pipe, and we could submerge everything but the point where the leads come out without having the windings in direct contact with the water. There was no noticeable attenuation of LEK's signal, and very little detuning with the loop almost completely submerged. Unfortunately the noise level was still very high. It looks like Bruce needs to add about 200 feet to his dock." Congratulations are in order for Bruce Koehler, who now holds amateur call AA0YB, having passed all his exams in one session. "He says our 1750- meter messages and QSOs helped him prepare for the 20 WPM code test. The FCC has really gotten its act together with electronic processing of new license applications. New hams can check in by voice or Internet to find out if their call signs have been granted, and may begin operating as soon as the call appears in the FCC database. The waiting period between taking the exam and getting on the air is now only 7 to 14 days." - Stephen P. McGreevy (RR, CQ; 45 Elda Dr., San Rafael, CA; e-mail: {{NOTE: GARBLED--SEE SEPT. ISSUE FOR CORRECTION}} 94903spmcgrvy@ix. netcom.com or s.mcgreevy@genie.geis.com) reports his MedFER beacons are off the air now until the next time he gets a chance to go on a DXpedition. "Back in 1993, I traveled all over the western and central US and Canada in my van, DXing beacons, LW, MW, some SW, making a great deal of Natural Radio recordings, etc. RR and CQ were heard as far as Manitoba and the Dakotas. Now, with a job in San Francisco, I am rendered mainly listening from home. While I used to heavily DX the NDB and LowFER bands, I really have more-or-less quit. Got up to about 600 NDB's." "I am very fascinated and in love with Natural Radio, however, as it connects me in another way with this beautiful planet. I've dropped many activities in order to simplify my life, and concentrate on enjoying nature. Natural radio falls into my enhanced interest and love for nature. Working in the big noisy city of San Francisco (in MIS) really has pushed me toward times when I can just get out into nature, and has also been an incentive to drop out of many other activities, such as TV watching (yecch) and most forms of comsumerism. I guess I'm sort of going down the path that Vince Pinto did. Anyway, at least I'm saving quite a bit for my planned/eventual permanent extraction from the rat race." He adds, "I would be interested in coordinating some natural radio sessions in the future." Mother Nature has rewarded Steve with some magnificent natural radio recordings, several of which he graciously converted to computer WAV files and uploaded to the Longwave BBS in the form of two collections. You can download them as VLF1.ZIP and CHORUS.ZIP, and I heartily recommend them. On the day he was sending those files, "I went out in the back yard to watch convective t-storm clouds build over the Sierra 100 miles to the east. I also decided to listen to sferics with one of my earlier WR-3 prototypes. I was astounded to hear nice, moderately diffuse whistlers-- about 1 per minute average--sometimes 2-3 per minute. Some of them are quite loud now. I grabbed my Marantz and better WR-3E whistler rcvr with excellent highpass and made a 15 min. recording of these unusually timed whistlers. This was at 2045 UT June 25. It's 101 outside, though it's dry heat. We thought summer would never arrive here in northern CA and now, we get 3 days of a heatwave--and daytime whistlers rivaling the better nighttime/ sunrise ones! Mother Earth is truly fascinating and unpredict- able!" Sporadic E propagation on FM BCB struck like a storm on July 5 or 6-- "three hours of skip to western TX and eastern NM from 2300-0200 UTC. Many signals were strong enough to override some of the San Francisco and surrounding area stations. But, the very best E-skip I ever heard (100 hours of it) was in GEORGIA the summer of 1990! FM E-skip is second most exciting DX pursuit to natural radio--maybe first, since it is rarer." - Bart Prater (VA, N4ZV; Rt 1 Box 496, Moneta, VA 24121), who is both a LowFER and a ham operator, says "I've got mixed feelings about an amateur allocation in the LowFER band--ten watts and a big antenna takes away the magic!" Taking advantage of the wettest June on record in central VA, Bart made a VXO to drive a balanced modulator, then followed that with a simple series crystal filter, using surplus color burst types. "Adjusting the VXO for a band pass peaked at 1.5 kHz, LSB, and using a variable cap shunting the output of the single crystal to broaden the passband a bit, this little exciter really talks." Suppression is 40 db for USB and carrier, and 6 db rolloff is at 1 and 2 kHz. "A simple mixer converts to the MedFER band, where the NLSBSC (Narrow Lower Side Band Suppressed Carrier... maybe I should just call it J.U.N.K.) exciter is a hands down winner over my old phasing exciter with its conventional 300 Hz - 3 kHz passband. Any thoughts on very narrow filtering for sideband transmission?" Bart says he may investigate the inexpensive Hallmark talking greeting cards for message storage. Footnotes. I have a knack for putting things I'll need later in safe places. So safe that I can't find them when I need them. That's what happened to a nice letter and photo from Brice Anderson, but usually such things turn up again. We'll try to have them next time. 73 for now. - - - THE 1750 METER BAND and THE TOP END (Combined columns for August.) While the flood of correspondence continued through mid-summer, reports of beacon activity have trickled off. Therefore, I think we'll skip both lists this time as redundant. If any new members don't have back issues and would like a copy of the beacon listings, however, I'll be glad to send them to you. Please include a self-addressed, stamped envelope with your request. We have only a few changes to each list, most of which are described in this month's Notebook column. The changes for LowFERs include: replacement of 166.66...kHz with 187.650 kHz for C, Morro Bay, CA; and temporary portable operation of SL on 186.225 in Minnesota. On the MedFER side, the changes are: 1637.93 RR San Rafael, CA and 1655.82 CQ Santa Rosa, CA, off until further notice; and 1638.30 SEA Warm Springs, GA, off until late September. Believe it or not, September is just next month! So please be thinking about your fall beacon activity and let us all know about it. Thanks. - - -