The Notebook (From the LOWDOWN, March, 1996) The Mailbag, News and Comments About LF Radio, Etc. John H. Davis, Box 367, Warm Springs, GA 31830 -E-mail: johnhdavis@aol.com -Fax: (706) 672-0964 No winter doldrums here! Interesting news from the digital front tops our list this time, and we have plenty of other correspondence as well. Here we go... Digital Mode Sets Pace for DX The promise of digital modulation schemes, for making full use of what little power is available to us in the noisy LF band, has apparently been realized. Since we last got together, California beacon HDO was successfully copied in Colorado and Minnesota! The best way to tell you about developments is probably to just pass along the messages more or less chronologically, from Cliff Buttschardt (W6HDO) and some of the other parties involved. On January 24, Cliff notified several of us: "Late last night, John West of Longmont, Colorado called and said that he was printing HDO(null) very well! I asked for further details in which John indicated that there was no signal to be heard, rather the synchronization was obtained by the computer and relying upon the synthesized frequency for accuracy. The signal was obtained just before dawn in Colorado, purposefully done to avoid intermodula- tion signals when the broadcast stations commence daytime operation. John's grid square is DN70KD while the Cuesta College beacon is located in San Luis Obispo, CA, at CM95NI. This proved to be a path of 923 miles (about 1,500 km). HDO(null) is on the air 24 hours a day and it should not be too long before others in the Mid-continent obtain copy. Many thanks to John for the effort and report!!" Indeed, that word was not long in coming: "1600 miles on 1750 meters!... Just a few minutes ago on Saturday, 3 Feb. 96, I received a letter from Lyle Koehler indicating partial printing of the HDO(null) BPSK beacon! As before, there was no audible signal, and Lyle did have to make adjustments after first noting that consistency was present in what jumbled characters he was receiving. A slight adjustment, part of the DeCarle BPSK program, fixed that. Then the usual happening----a computer birdie swept past and wiped things out. These observations seem best just before dawn at the receiving location, in this case 1200 UTC. Whether is this is propagation or simple lack of broad- cast intermodulation is one of the items all this experimentation is about!" The receiver was Lyle's new ICOM IC-706 with a 250 Hz filter. A followup letter from Lyle says, "The only thing to add is that at about 11:30 PM on the same day I first acquired his signal, I was able to get about 6 minutes of continuous error-free printout of the HDO identifier. The frame grabber was set to 128 samples at the time. I should also clarify that the receiving antenna was my old faithful 8-foot loop ... John West has sent me a prototype MAX800 receiver. I'm struggling to finish my latest homebrew receiver project so there will be enough room on my tiny workbench to try some experiments with the MAX800. Preliminary tests show that I need to enclose the MAX800 in a metal box and provide some isolation to get rid of computer-generated noise." Then, from Cliff on Feb. 4: "Another letter came from John West and he is now printing HDO(null) in the early morning and at times, full pages of copy!" Bill de Carle indicates that, "Apparently WA4ZIA is also going to listen for BPSK sigs." This is already quite a series of feats for one season, and it would be really remarkable if reception can be obtained this far east. There's a westward listening effort, too. In late January, Cliff mentioned, "The HDO(null) beacon....has been reported as an aural signal on the Big Island (of Hawaii). We bought John West's old prototype board just to be sure that we have at least TWO working models, and that will be shipped to Hawaii just as soon as I can package the boards. The DSP synthesizer that Dave Curry has been working on has been completed. It appears to be a gem and switches automatically to exactly 800 hertz from where it transmits for receive. The idea of building a stand alone sythesizer and using it with a narrow band AM receiver which produces EXACTLY 800 Hz audio seems to work far better than any of us anticipated!" "As before, we can always use listeners on 187.65...." Efforts to begin producing receiver kits have suffered setbacks, but several of the parties involved are still hopeful. We're On The Web! Everybody and his cousin has a presence on the Internet these days. If you browse the World Wide Web, you'll find home pages of all kinds...from people who want to sell you something, to people with kooky ideas to promote. Well, why not longwave? Now we're there too! If you go to http://users.aol.com/lwcanews/lwcanews.html you'll find the Longwave Home Page, looking somewhat like what you see on the next page here. The exact results depend on which browser software you use, of course. It's very much in its infancy, and exactly how it grows will depend a lot on how you want it to. For those who haven't taken the plunge into communicating over wires (it's how Samuel F. B. Morse really intended for us to do it, you know), this home page isn't just a static document. Underlined text is "hot." That is, if you position your mouse pointer over it and click, something is supposed to happen. If you click the line under Latest LF News that reads "Digital mode sets record DX," your browser makes a few more quick calls to the AOL server. In a couple of seconds you'll see another page that has a colorful graphic at the top, and part of the news story on the BPSK DX records. Or, if you click "About the Longwave Club," you get information on why you should join the LWCA and how to do it. Web pages can also be linked to each other. Mike Staines and Jill Dybka are just two of our members who have Web pages, and have included LF-related hobby areas in them. By clicking the underlined references to them in the Longwave Home Page, you'll be connected to those pages and can browse any and everything they contain. Or, by clicking Steve McGreevy's underlined name, you'll be linked to the University of Iowa server where many of his best natural radio recordings are archived and are available for downloading. Web publishing can be a great cooperative effort. I invite all members who'd like to have Web pages relating to LF to produce them and let me know about it. I'll be glad to include links to them on the Longwave Home Page, and I hope you'll be inclined to do likewise. The only thing I ask editorially, though, is that Web pages to be linked should be suitable for a family audience, and primarily hobby oriented, without significant commercial or political themes. (I'll gladly mention any Web page that may be of interest to radio hobbyists, commercial or otherwise; but at this point I'd be inclined not to actually link those that don't directly relate to the objectives of the LWCA.) Future of the BBS? If your columnist is dabbling with the Internet, what does this portend for the future of the Longwave BBS? A good question, and I'd like your advice. Right now, the Longwave Home Page and related files occupy a very limited space on the AOL server. This is fine for getting the attention of casual Web surfers, but it's not suitable for "preaching to the choir." To provide a decent base of radio-related files for our members and serious newcomers to access, I'd have to rent more storage space from AOL or another Internet provider. Renting space on a Web site is not terribly expensive these days. For about the price of the BBS's phone line, I could have 20 or 30 megabytes of file capacity. At first, that sounds attractive from an economic standpoint... swap a phone line for server space, and not have to worry about whether the computer running the BBS will survive the next storm or another year's wear and tear. But there are a couple of drawbacks. For one, 20 megs is not really very much storage space these days. It's a small fraction of what the current BBS can hold, so I'd have to continually select only the most popular programs and files to keep there, and that would add to the work instead of reducing it. Also, even though the bulletin board's message system is used less than I thought it would be, several members do depend on it for communication with each other and with me. Perhaps some middle ground would work. What if I were to lease server capacity, and keep the BBS, but have it share a phone line? There would be a chance you'd encounter busy signals once in a while, and I might not keep it on as much in the daytime. But it would remain as a repository for our full file collection and e-mail. Would this adequately serve our members' needs? Is an expanded Internet presence a good idea too? How many of our members are actually able to use BBSes, and how many can access on-line services? These are things I'll need to know, so I'd appreciate your comments. Please watch for a survey announcement soon in this column. I'll be looking forward to hearing from you on this subject. LF Converter Update The January article, "A High Performance Low Frequency Converter for 1996," has generated quite a bit of interest. Author Tim Brannon (KF5CQ, Dallas; e-mail: 76546.1311@compuserve.com) reminds potential builders of the importance of local oscillator isolation. "I've received a lot of correspondence this month and I'm very happy that so many members enjoyed my converter project. However, one fine point of construction which I need to emphasize is the need for isolation of the local oscillator away from the post-mixer amp circuitry. This is especially important if the LO/buffer amp/Filter 2 circuits are not assembled inside a separate shielded box. Otherwise leakage of the strong L.O. signal around the mixer may cause some blocking in the IF receiver and thus defeat the major benefit of the doubly-balanced mixer. I strongly recommend using the shielded box." "Also, be sure to keep the coaxial cable leading from Filter 2 to the mixer AWAY from the post-mixer amplifier circuitry for the same reason." From The Mailbag... -Bill Bowers (OK; PO Box 399, Davenport, OK 74026) has been asking himself a question many beacon operators do. You may have to shut down your own transmitter if you hope to hear anyone else on the band when listening at home. How many times have you thought, what if someone's trying to listen for me right now? Bill speculates: "I wonder if there is any way to work out some schedule for turning off for listening. Maybe the eastern/central regions could be divided into four quadrants and listening periods designated. I am not sure how this would work, but there should be some way to organize it. Maybe just assigning arbitrary numbers to each LowFER for the hours they may be off the air for listening. this does not mean you would be required to turn off for the specified hours, but it would alert listeners that a particular LowFER could be off the air on some known schedule." As ruggedly individualistic as many of us are, it might be difficult to coordinate such a thing, but perhaps it would not be too much to ask that we include possible off-times in beacon listings. It might be awkward to fit any more information in there, but I'm willing to try if the readers want it. It'd be "most likely off times" rather than anything definite, of course. For instance, when I shut down MedFER SEA to listen, it's usually between 11 PM and 1 AM Eastern, but I don't do it every night and hardly ever for that whole time span. I'd have to indicate it as a possibility somehow. Bill has another question, this one for owners (or gurus) of the Drake R-8 receiver: Is there a way to change the BFO offset from the stock value of 800 Hz to 400 Hz? If so, please drop him a line at the address given. And, he's one of several people especially glad to have TEXAS back on the air. "I pick him up strongest around noon every day. It sure is nice to have that signal, as I use it for all my antenna tests." -Brice Anderson (BA, IE) wrote on January 30, when it was 0 deg.F in Lancaster, IL. The day his letter arrived, we reached the same temperature here. Hmmm. He indicates LF conditions were deteriorating. Regulars WI and TH were spotty; KRY was consistent, but not much above the noise. TFQ was strong most of the month, and John Hoopes was hearing BA, but Brice hadn't copied JDH yet. Brice has been trying for a QSO with ZIA "but we never hear each other at the same time, hi." He passes along word that ZIA has been heard in Orlando, though. Other who-heards: BOB heard BA while portable near Chicago. MedFERs SEA, MIN, and STLMO come up to useful levels briefly every 5 minutes or so, but fade swiftly, he says. During one such opportunity, Brice's IE and Lyle's MIN managed a QSO. (This was after a new 2N3094 in IE's final, necessitated by some lightning in a snow storm the week before.) He reports GDY was "getting clobbered" by a broadcast signal. Brice and Lyle both observed an unexpected difference in propagation between the 160 meter ham band and the MedFER band. During the CQ WW 160 contest, Brice had 50 QSOs with stations in Europe, South America, Hawaii and Japan, but MF conditions were not nearly so good. - Lyle Koehler (LEK, MIN, K0LR; Aitkin, MN) started off his message with "not much happened during December," but that hasn't been true lately; see the BPSK news earlier. Lyle also bought an ICOM IC-706 transceiver, and sends a "mini product report" on it. (Download file IC706RPT.TXT on the BBS.) He notes: "My synthesized homebrew LowFER receiver had some frustrating bugs and is taking longer to get going than it should. However I've already been able to hear a number of LowFERs with it, and copied JDH for the first time on February 6th. He's my best CW DX so far at nearly 1100 miles. When the receiver is finished I'm hoping it will also work well for BPSK." "The total list of LowFER signals received at this location is now up to 19 for the season. On CW, I've heard KRY, 0KVL, YB, JDH, XJ, BWY, BA, BK, ART, MEP, WI, ZIA, SAM, ARK, TH, RM and OK. The only BPSK signals 'printed' on the computer so far have been MAX and HDO." "I've been able to copy VA and QSO with IE on their new MedFER frequen- cies. D is still readable here occasionally, but the other night the (Army Broadcast Service mobile AM station) was testing with power levels from 500 to 5000 watts on 1670 kHz with lots of sideband energy at 1675. WNYB is also on the air on 1620. Henry's STLMO beacon is still in the clear and readable here just about every night." "We've had enough winter weather to last us for a while, even though we were enjoying a balmy 42 degrees below zero while Tower, MN was setting a new state record of -60. This area also escaped an ice storm that hit the Twin Cities, taking down the ART, YB and SAM antennas. ART already has his antenna repaired and YB should be back on the air soon, but it may take a little longer for SAM to rebuild." -John T. Collins (P, KN1H; RR2, Box 427 Cornish, NH, 03745; e-mail: jollins@vtetv.org) says, "Just wanted to notify you and the Lowfers that my beacon 'P' is on the air on 186.32KHZ and seems to be working alright. For now it will be on every evening and all weekends. It's a VN66AF at 24V, 41ma into a shunt-fed Rohn 25 tower 38feet high (including a mast). Obviously a full 15 Meter long antenna would work better, but this is what I have at the moment. Since I've never heard another LowFER from New England I figured any beacon at all would be better than none! I hope someone hears it!" -Will Payne (YWK, Dallas, GA) spoke of our Southern taste of winter, and one benefit it brought. "We have an exceptionally hard freeze here plus 1 - 2 in of snow, and I have finally heard some LOWFERS, to my great delight! Swept the LowFER band twice, skipped NDB listening, shut down the Rycom and restarted YWK. Hope someone out there heard me!" His reception took place on Feb. 5 using a Rycom 6040, and 500 ft wire under snow for the antenna. Signals, times, and received signal strengths were: WI 0650 "VVV DE WI WI WI WI WI WI ", -85 dbm XJ 0658 "XJ XJ XJ XJ XJ XJ XJ X1 ", -90 dbm 184 kHz, UNID voice, 0706 in noise -93 dbm "Heard XJ again Tuesday night, but he suddenly stopped TX at 0226 UTC. Started YWK; hope he heard me!" "Am trying to interest Ray Sanders, KS4EG here at Lockheed, who is a notorious DSP fiend, in audio filters, or even a complete DSP receiver DC to several kilohertz. I saw in back LOWDOWN issues a project which digitally integrated a time domain replica of the input signal, synchronized with the AC line, in perhaps 2048 samples, then subtracted it from the audio being processed, effectively removing anything with a 60HZ autocorrelation. It was fairly involved, with TTL logic running some SRAM and A/D and D/A, but it strikes me as a particularly sound approach in theory. Ray believes it can be done in his DSP engine, but he is still intent on the HAM BANDS and wants me to design an RF front end for his DSP receiver/exciter. Maybe we will trade favors." -Robert Schneider (new E-mail address: rs@uni-wuppertal.de) is interested in digital signal processing, too, and recently got a DSP56002 Evaluation board. "I read about it in QEX, and the next day ordered one at our local Motorola distributor. Now I am trying to get familiar with the instruction set. The last time I programmed in assembler was in the old Z80 days. But there exist some very nice applications written by other hams." His FTP site continues at: ftp.uni-wuppertal.de:/pub/pc/lowfer. -Bruce Koehler (YB) checked in to the BBS just as last month's issue was going in the envelope to headquarters, and in the rush I managed to mis- identify the beacon in my little addition to the 1750 meter column. (Sorry about that.) What Bruce was trying to tell us was that "we had a big ice storm here today, with wind gusts near 50 MPH. I was listening to local LowFERs LEK, BK, 0KVL, and RM using the YB transmitting antenna as a receiving antenna (my loop was covered with ice), and heard a clunk on the roof. Suddenly all I could hear was LEK. I looked outside and noticed the YB wire from the top hat had broken and fallen on the roof. The top hat is still dangling from the cottonwood tree. BK's signal is way down too; the antenna and loading coil must be covered with ice at Shell Lake. LEK is still strong, Lyle missed the ice but got about a foot of snow." -Mike Staines (mike@bluefin.net) Reports, "There was quite a band opening around 10:30 pm local time tonight (Feb. 4). TH (Carl in NJ) was VERY strong so I tried listing around. Heard KRY for the first time. He was RST 219 average, but LOTS of QSB and was quite strong for seconds at a time. The Euro- broadcasters were all over the place and were so strong that their sidebands were wiping out anything else. The Timewave DSP-59 helped with KRY but was not needed for TH and WA." Mike makes a request for Lowdown articles on ULF transmissions, below 10KHz. "I am checking on access to about 10 miles of old telegraph line that runs next to some railroad tracks up here. Thought it would be a fun transmit antenna at those freqs." New member Carlton Davis recently asked for some ideas on this same part of the spectrum too. It would be a great opportunity for a would-be writer with some experience in this area to share some helpful information with our readers. -Bill Hensel (D, AA0RQ; Englewood, CO) has just acquired an E-mail address: AA0RQ@AOL.COM. Among other things, he will be using it to submit reports to us. He notes, "I am hearing STLMO occasionally around 0230 UTC. A rogue beacon exists on 4095 KHZ. It is out of Arizona and sends dashes, and another on the same freq. sends dits. They are 100 mw beacons." -Frank Cathell (TSN, Tucson) also made mention of these, and updated us on several other items. He reports MedFER TSN went on-air as scheduled on January 1, and has been heard in the San Diego, Los Angeles and Kingman, AZ, areas so far. Located 25 miles north of Tucson, his present site is actually quieter than the former mountain location at Descanso, CA. "I have managed to copy MedFERs A, D (very consistent every night), RR, and possible traces of MIN and STLMO." "Longwave has been the real surprise, with multiple receptions of LowFERs PLI, NR, and M, using a 4 foot long active whip (modified LF Engineering L400B) 8 feet up. Beacon M is generally readable 24 hours a day, while PLI and NR are easy nighttime copy." -Doug Williams (OER, KB4OER; new address: 135 Hughes Road, Watauga, TN; e-mail: d.williams@ilinkgn.net) says beacon OER will not be on the air this season. "I have too many irons in the fire and the beacon had to take a back seat. I hope to do the rest of the antenna work this summer and have it on the air by next season. I haven't had time to do much listening, but I hear beacon WI on occasion." -David Jones (NR, Columbus, GA) writes, "Saturday night (Feb. 10) from seven to eight, I listened mobile at the future American Indian stickball field near Fort Mitchell, AL. I heard RED YD JDH and WI. That is the first time for Cecil's beacon." David also recently met Harry Lanier (KF4VK, Valley, AL), one of the great evangelists for the longwave radio hobby. (One thing your columnist has particularly missed since selling the old 2M HT is visiting with Harry on the air.) -Nils R. Bull Young (WB8IJN; e-mail: nyoung@nova.wright.edu) is one of our newer readers. "I just got the January edition of The Lowdown as the start of my membership in LWCA kicks in. Great stuff. I am surprised at the number of people who are involved in VLF/LF/MF experimenting. If I'd know that there this many loonies around, I would have gotten into this earlier." "Right now I'm just playing around with Ls and Cs, listening between 160 and 190 kHz and between 1.6 and 1.7 MHz on my TR7. It's an old beater but it works. Soon enough (as in: as soon as I get some other stuff out of the way and get the boxes built and such), I'll be putting a 624 Kits convertor into the receiver antenna hole of my Argosy. I think the Argosy/convertor deal will work better than the TR7, which appears to be prone to picking up its own signals as well as the intended stuff on the bands of interest. Especially at 1750 meters." "This all wouldn't have happened, however, if one of the guys in the Wright State University (near Dayton) instrument shop had not given me a big chunk of pvc pipe.... 8.5 inches in diameter and about 6 inches long. I wound a coil on it with some surplus wire and tuned it with a 500 pf cap. Picked up XJ (about 35 or 40 miles from here) on two occasions over the Christmas holiday. Haven't heard him on since." "Then I messed with an old LF/MF tuner that I'd build years ago and picked up (Latin aero beacon) MER on about 1685.6 kHz a few nights ago. Nothing I've heard yet bangs the meter needle on the peg. But that I'm used to, being a QRP loonie as well. I'll let you know when I get some beacon's peaking around here. Plan on putting one on soon enough, using the initials of my name as a call: NBY. Figure that four letters is at sea, and even as confused as I am, I know that I'm not standing at the rail any more. So I'll be a shore station with 3 letters and be happy." BEACON BITS: Donald Moth (MPK, Chittenango NY) heard KRY at 9 AM Eastern on February 3. Maybe the -6 deg. temperature helped. Don uses a 45-foot square loop strung between two ham towers, and regularly copies ZWI, SVZ, and TH. -Jim Hagan (WA4GHK, Malabar, FL) ran across W (179.6) in January, very strong at 20 miles distant; "not even in CW mode when I found him." He also heard YD that same afternoon. At night, ZIA is a regular, as are WI and TH to varying degrees, and KRY came in very well on January 29. -Ron Barlow (N4GJV) says hopes to put a signal on this year are looking improbable now. He has been hearing XJ, KRY, TH, VA, WI, NI and ZIA though. -Hank Holbrook (Dunkirk, MD) sent a nice reception report on SEA on January 22, weak to fair. About that time, PX was strong, ABC-1643.5 fair, and GDY was good (plans to QSY due to QRM, apparently). We'll have several more loggings from Hank next month. Meantime, he copied the Army's KTRK test, and has heard two unidentified beacons: SN on 1650, and RWN on 1677. Any ideas on these? Footnotes. Three years! This is column number 36 for yours truly, and if I don't think about it too hard, it scarcely seems like one season. You'll probably find lots of typos in this one, for which I apologize in advance. I've been transposing letters a lot lately, and hitting some completely off-the-wall ones, and there's no reason to believe I've caught even the majority of them this time. We've been intensively engaged in questionnaires and focus groups at work, on behalf of two different sets of consultants. (One set is to determine what we should be paid. The other is to tell us if we'll be needed at all in the future!) All of this had to be done in less than two weeks, with only a few days' notice to us...of course. We'll take up where we left off next time. If we're lucky enough (maybe that should be _un_lucky), we might have another April 1 visit from the notorious Mr. Answer Guy. Til then, 73. - - -