The LF Notebook The Mailbag, News and Comments About LF Radio, Etc. John H. Davis, Box 367, Warm Springs, GA 31830 - E-mail: longwave@mindspring.com - Web: http://members.aol.com/lwcanews/ *"If you build it, they will come." We're well into baseball season now, but this quote applies to the Longwave Home Page as well. It would be more dramatic if I could tell you some mysterious voice told me this before I started plowing up Web server space and blundering into the world of Hypertext Markup Language. But truthfully, I didn't have a clue what would happen. I figured maybe a few dozen people a month would discover it. Later, after the big transition from BBS messaging to e-mail last summer, I revised my estimate up to (what I thought was) an optimistic 100 or so hits per month. I wasn't even close. According to Pagecount, the advertising service that provides the counter we're using right now, the Longwave Home Page has been accessed 871 times in the first 17 days of April! This figure is strictly for the Home Page itself. It doesn't indicate how many times the associated pages, such as the Message Board, were accessed directly without going through the Home Page. After finding out that America (Sometimes) Online now provides counters too, I added them to a few other key pages, and discovered that the Message Board is read about 10 times a day. The page of comet links (no longer available) is hit seven times daily, on average. Even Mr. Answer Guy's silliness is visited about five times a day. Pagecount also provides a summary of where the Home Page's readers are located. As you would expect, the bulk of our readers reach the page through U.S. commercial and network Internet service providers (.com and .net), with 19 hits from U.S. educational sites (.edu), one from a U.S. non-profit organization (.org) and one from a U.S. military facility (.mil). There have been hits from one particular government (.gov) site almost every day, though I have no idea who it is. Outside the U.S., it is no surprise that Canadian Web surfers found us most often...33 times. It's not surprising, either, that Japan was next, with 28 hits. But would you believe Sweden comes in third, with a count of 25 times? Finland followed with 14, Germany with 12, nine each from the Netherlands and the U.K., and seven from Italy. Also on the list are Portugal, Norway, Belgium, France, Spain, Ireland, Malaysia, Australia, New Zealand...and even the Faroe Islands! A long Notebook column next month. I'm already working on it, having plans to be gone for a few days about the middle of May. As a result, I'm bundling up some of the long-delayed feature material and some of the less time-sensitive news for the June column. We'll have very abbreviated versions of the beacon lists ("just the changes, Ma'm"), but they'll probably return in July. Did I call March "cruel and treacherous?" Well, one of the ways it lived up to that reputation this year was by changing places with April! After warmth and early blooming and spring storms in March, we've returned to flirting with near-freezing temperatures and semi-drought well into late April. Of course, there are some of you who would be very happy with those conditions right now, so I'm not complaining. It just goes to show, though, there's no such thing as "normal" weather. Communications breakdown. I've long suspected that AOL sometimes misplaced my e-mail during unexpected crashes, or regular maintenance, or just at random, and we had good evidence of that this month when John Reed sent an article as a file attachment to e-mail. Fortunately, he surmised that it had gone astray and sent it again. When sending me any e-mail, please be sure to include "Longwave" or "Radio" or "Beacon" or similar words somewhere in your subject line! You wouldn't believe the amount of junk e-mail I receive. My first task every day when I log on is to delete the clutter so real messages can get through. I guarantee that if you use words like "Opportunity" or "Free!" or "$$$" or "2,000,000 Internet addresses" or "Hot!" or "Don't miss out" in your subject line, that mail will be zapped without a second thought! In fact, mail that arrives with "Hello" or "No subject" on it may be deleted unless I immediately recognize your name. It's absolutely astonishing how much junk arrives under those headings. Since junk e-mail is now a fact of everyday life, it's therefor wise to make your subject line truly descriptive...not just when sending to this column, but for all your e-mail correspondence. It'll really help the person at the receiving end. *A Top End Update. Just as I was preparing to mail this month's columns to headquarters, I received some additional material from Dick Pearce on the Dallas-Ft. Worth Airport TIS stations. You may have heard stories that these signals have been heard in New Zealand. Although you shouldn't accept half of what you hear on the Internet, this story may be true. Dick forwarded a letter he received from an American Airlines official, confirming that they've received e-mail from New Zealand about the transmissions. More on this next time. BPSK Update Digital communication by radio is really catching on, and BPSK is leading the way among modulation methods. Most of this month's news on the subject comes from Lyle Koehler, so I'll let him fill you in: "The BPSK tests on the ham bands have been very useful in a couple of ways. First, they have proven that BPSK operation is not limited to propagation paths with long-term phase stability. Amazingly, signals on 80 meters will continue to 'print' even under rapid fading conditions including severe flutter probably associated with aurora. Another benefit of the HF tests has been a series of significant improvements in the COHERENT software." "At the moment there are half a dozen amateur stations with two-way BPSK capability scattered from coast to coast, and you will usually find some activity at about 0300 UTC on 3591.000 kHz. We start out at 40 baud (MS25 in the COHERENT software) without the error-tolerant (ET) mode, and switch to ET if necessary to improve the copy. We've also run successful BPSK experiments on 160, 40, 30 and 20 meters. When the QRN chases us off 3591 kHz, the activity may shift to around 7081 or 10,141 kHz." "All that's required for BPSK reception is Bill de Carle's 'Sigma- Delta' board, connected between the receiver audio output and the computer's serial port. To transmit BPSK, we simply take a very stable audio reference tone (which can be derived from the crystal-controlled clock on the Sigma-Delta board) and use an exclusive-or gate or double balanced mixer to produce the binary phase modulation, then feed it into the audio input of a transceiver in the SSB mode. The BPSK experimenters are using various combinations of modulating tone, bi-phase modulator, and low-pass or band-pass filters to clean up the audio signal before it goes into the transmitter." "Everyone is using something slightly different, and all the methods seem to work equally well. It doesn't matter exactly what audio tone is used because the frequency of the SSB transmitter can be set to whatever is necessary to put the output tone on the operating frequency. For example, I'm taking an 1800-Hz square wave signal from the Sigma-Delta board, running it through a bandpass filter to turn it into a sine wave, then through a home-brew double balanced mixer and a simple R-C low-pass filter into the transceiver's audio input. Total parts cost for the transmit interface is about 10 bucks. The transceiver (several of us are using ICOM IC-706's) is set for 'split' operation. On 80 meters the receiver is tuned to 3591.000 kHz CW with the narrow IF filter, and with the BFO pitch set for 800 Hz." "The transmitter in my station is set for LSB mode at 3592.800 kHz, so that with a 1.8-kHz modulating tone the output is at 3591.000. A transceiver with the high-stability reference oscillator option is recommended, although I don't have one in my IC-706 and it seems to be stable enough for BPSK QSOs even on 20 meters." "By now we have operated on 160, 80, 40, 30 and 20 meters. Dave, AA1A and Bill, WB6RIJ were the first to span the continent (Cliff, K7RR was at sea, literally, but has since worked Dave on BPSK). COHERENT is up to version 6.0 and incorporates some great convenience features that make BPSK QSOs almost like a hardwired duplex keyboard-to-keyboard connection..... I'm hoping the end result will be some new DX records for LowFER and MedFER signals next season." We also have word on the subject from Dave Riley (1A, AA1A; daveaa1a@pcix.com): "A dozen years ago one could hear many beacons around the Boston area and actually get on and call CQ and get an answer... Today almost nil... was a dull season on LowFER, but we did get connected to the BPSK folks and have discovered communications with them on 160-80-30-20 meters. My setup is a Sigma-Delta board from Bill, VE2IQ, which is a bargain and performs very well. Mine is mounted in a A/B serial port switch box along with the transmitter modulator. The 'B' serial connector was removed and replaced with RCA jacks. A real nice house for $9.95." On To The Mailbag -Bob Hoffswell (BOB, AA9DH; Mahomet, IL; BOBharvey@prairienet.org) writes: "I just wanted to report that LF activity has been pretty low here in Mahomet. I seldom hear Brice anymore and YHO is rather weak. BOB is still on the air 24hrs, even in storms, but I'll have to remove the radials and ground screen soon to allow for grass-mowing. I'm going to make some 100-mile-away readings tomorrow and again in a few weeks after I remove the radials, etc. If things are really poor at that distance, I may take BOB off for the summer, except for some experimenting with a mowable ground system-perhaps some sort of tuned GP. Until then, BOB is on and I will advise you of my decision to stay on or turn off for the summer." "At present, I'm back working on reseeding the HF antenna farm here, which lost a major antenna this winter. For the past few years I've been playing with short, high-efficiency, helically-wound dipoles. They seem to work as well as the big guys on 30 and 40m (efficiencies are over 50%), and a 25' vertical on 160m worked well. It could offer interesting possibilities as an alternate LF antenna, or portion thereof." -Brice Anderson (BA, IE; Lancaster, IL) indicated that winter still had a grip on southeastern Illinois in late March, but signs of green were showing. He has taken MedFER IE off for the season. While BA remains on, the extensive radial system will be rolled up for yard work. Though the latter was on all winter, Brice reports only BOB and XJ heard it regularly. He feels conditions were sub-normal this winter, and reports hearing KRY, and TFQ only up until February 11, but not since. ZIA was last heard Feb. 12, and TH was heard on Feb. 17. "I can hear BOB and YHO every day, although BOB is getting weaker as the season progresses. Also YHO. My hand goes out to them for keeping their beacons on the air! MF has been very poor, but I can usually find MIN and STLMO. Deep and prolonged QSB is the rule." -Pete Smith (Z, K7ZTM; Layton, UT 84041) indicates he is considering a call change from Z to ZTM for his beacon, to make it easier to copy, and is still attempting to improve signal strength with a new antenna. And, would anyone know about a station on 186.20 kHz sending a sequence of 11 dits followed by "CS" in a continuous fashion? "His signal strength is just above the noise level. Sure would like to know who it is so I could let him know we heard his signal. Have a nice summer." -Ken Mills (Pullman, MI 49450) sent a nice letter, plus a short article that may appear next month. On behalf of other recent converts to LF, he asks exactly what is meant by BPSK. We'll probably have a short summary on this again soon, but in brief, it's a modulation method in which the phase of a carrier is inverted by 180 degrees to denote a transition in digital data (in the sense used here, normally ASCII characters transmitted at a specified bit rate). It has considerable noise advantages because it can be detected coherently, among other features. "I have been a brass pounder for 40 years and am finding welcome relief in searching for low power NDB's. Of course, a lifetime of experiences from Ford Tri-Motors to Lear Jets to homebuilt Steen Skybolts may explain my interest in NDB's. QRP operations here are meeting a challenge as part of an emphasis on weak signal detection. It seems to me that BPSK might offer some opportunities for accomplishment in this area. I have yet to hear a LowFER, and I listen most every night." A relatively quiet spot on 92 acres of woods may help, though. Ken expresses appreciation for Ken Cornell's Scrapbook series, recommends Ken Stryker's Beacon Guide, and also thanks Bill Oliver and the various LOWDOWN writers as well. -Lyle Koehler (LEK, MIN, K0LR; Aitkin, MN; k0lr@emily.net) also has a regular report this month. "QRN has been really bad on the rare occasions I listened lately. LEK and MIN are still running, but none of the other local beacons have been on the air for the past couple of weeks...nothing but static crashes and power line carriers on the LowFER band. However, I got an E-mail message from Jim Strong, K0PM in Princeton, MN, recently. He has been hearing beacon LEK for a long time and finally found out where it was located (probably through the Longwave Web page). This morning (April 13) I heard Jim's beacon for the first time. It is presently operating on 181.50 kHz, using the repeated character 'I' as an identifier. Jim will probably be using a different ID in the future. It's nice to have a local LowFER beacon to listen to again. Band conditions at 0945 local time were very quiet. I could hear a faint but identifiable signal from OK, as well as the third harmonic from WWVB on 180.0 kHz. Just checked again at 1400 CDT -- still hearing I and, amazingly, OK." "It's that time of year again. Our grass won't start to grow for a couple of weeks, but the snow is almost all gone and I should be rolling up the ground screen for the MIN LF beacon before the grass takes over. Time to start thinking about new antennas and projects for next season. Although Aitkin is located on the Mississippi, the amount of flooding here was very minimal. Nothing like the terrible mess in other parts of the state where rivers reached record levels." "On a sad note, I've lost another long-time friend and fellow experimenter. Arthur J. Mundy, W0YFZ (LowFER ART) died suddenly on Friday, April 11th, at the age of 78. Art was active in many aspects of the radio hobby over the years. At the time of his death he still headed up the volunteer examination program for the Anoka County (MN) Radio Club." -Tom (Doc) Gruis (D, K0HTF) checks in to confirm "D is still at it!" and update us on his contact information. -Darwin Long (DJL; Thousand Oaks, CA;) writes about DGPS beacon AE, at Point Atkinson, BC. "I have noticed most loggings of DGPS beacons to contain no ID's. If one listens to these beacons either in AM or sideband mode, no intelligible ID will be found... in almost all cases." "There always seems to be that little exception to a rule. Case in point is a DGPS beacon near Vancouver, B.C., at Point Atkinson L.S. About three years ago, before the implementation of the DGPS system, I was on a vacation to BC, as I usually do each summer to assist in an ongoing study of nesting common loons. As usual, my LF receiver tags along. NDB AE at 320 kHz was transmiting its continuous dit-dah dit dahhhh, like most normal Canadian NDB's do, using a clean shift of +400 Hz." "However, last year, DGPS was in full swing in the Northwest. I again tuned in 320 kHz while on the B.C. southwest coast. There was AE transmitting its Morse characters, with a new twist. In AM mode, AE was coming through as a warbly 400Hz +/- 25Hz shift, instead of a clean 400 Hz shift. It seems that this DGPS beacon is an NDB converted for use as a DGPS beacon. The shift oscillator was left keying (at 320.400), while the 320.000 kHz oscillator had been replaced by an MSK shifting oscillator centered at 320 kHz, for the RTCM SC104 differential correction data broadcast. Apparently, leaving the shift oscillator (used for the I.D. beat) has no deleterious effect on the DGPS operation or useability by DGPS equipment. At my last listen, on 3/25/97, around 12:30 local time from here in Southern California, it is still operating this way. I'll check it again in person this summer when I go back to B.C. "If the 'new' DGPS AE is zero-beat, AE keys in clean 400Hz beat tones in the receiver. It is the only DGPS I have heard so far as having an ID. If anyone else out there reading this has heard DGPS beacons with I.D.'s, could you let me (and any other pertinent logging/NDB entities of LWCA) know about it? I do have audio recordings from Vancouver, of AE 320 in various modes for your verification." "I might be crazy, but let's hope AE 320 sets an example, and other DGPS beacons add ID service to again render the possibility of identification, just like the good 'ole days with marine RDF beacons. Maybe we should write some letters..." -David Jones (NR, AD4NR; Columbus, GA; d.jones160@genie.com) alerted us to the late-April sequence of INTMINS tests from the Mir space station in time to get word out on the Web page. He reports the April INSPIRE Journal indicates no one has yet received previous Mir transmissions. The most recent series of Mir passes included some very good ones over the U.S., including one on April 26, at 8:23pm, passing over Grenada, Mississippi, southeastward to Jacksonville, Florida. David will be trying for that one, as will your columnist. We'll let you know next time how it worked out. David also notes that "Bill Pine editorialized about the loss of Omega next September. Omega not only is a simple check on the usability of a receiver, but gives the precise timing needed to correlate the transmissions with the tapes. Most spectrograms in the Journal have Omega lines on them." Alas, he also adds: "I got a letter from the Navy Observatory which says they will close down the Loran-C on January 1, 2000. I have dozens of pamphlets from time and frequency manufacturers. Loran-C is a natural for synchronizing their devices in spite of the increased accuracy an compactness of GPS. I have just two and fraction years to get my Austron standard receiver working." -Stan Forsman (caengrav@aimnet.com) ran across an unusual signal last month. "NUD-347 (US Navy, Adak Island, Alaska) was using a DA3ID format with a long 30 second cycle time. When I talked to them on the phone, they informed me the odd format indicated the backup transmitter. The primary was dead and the secondary unit had been built and installed in early 1941! As the base was being mothballed, they were not certain as to whether the NDB would be kept on-line." "My equipment consists of an old National RBL-5 receiver and a 100ft longwire antenna. My location is rather noisy, especially between 200khz and 300khz, but I have been able to hear and verify just over 380 NDB's since 1988." -Jon Iza (EA2SN) checks in from Spain this month. "Things here are a no-no on LW, for I have too much work to do and little time to spent on radio. However, I did listen to HAARP transmission from Gakona and read the CW on 6.990... 3.400 was covered with nice classical music." "On the LW/BPSK side, I'm finishing my delta converter since I recently got a bunch of audio-transformers to isolate the board and the computer. I had a very bad ground loop with 70 volts or so between them. When connecting or disconnecting, it hurts! Good news is that I travelled to The Netherlands and attended the National Dutch Fleamarket, mid March. Got to a table and saw (for the first time on my life) a frequency selective voltmeter. It was on top of a (twin) frequency generator. I saw a tag of 100 Dutch guldens (about 75 US$). I said to myself, OK, I'll come back. Wandered around, shopped some, and, when leaving I went back to get the voltmeter. I gave the guy a bill of 100 gulden and while trying to carry the voltmeter, he told me 'No, for 100 you may get both!'" "So there I was with two big and heavy boxes but a happy camper. The rigs are Wandel und Goltermann (The voltmeter is an SPM3) and I am looking for information. Built as a tank, and surely nice. Now, to build an antenna to log those beacons..." Footnotes. Just a brief reminder that the beacon lists will not appear in their usual form next month, but that this column will have plenty of features and (hopefully) all the news you can get in my hands by May 20. Meantime, keep informed by checking in on the Longwave Home Page. In April, it was the place to hear about another Coronal Mass Ejection from the Sun, as well as the Mir transmissions meantioned earlier. Who knows what last minute, fast breaking news might appear there? And, of course, let us hear from you soon. 73. - - -