"The LF Notebook" (from The LOWDOWN, November 1996) The Mailbag, News, and Comments About LF Radio, Etc. by John H. Davis Box 367, Warm Springs, GA 31830 - johnhdavis@aol.com - Longwave BBS - 706-672-0360 -Fax - (706) 672-0964 -World Wide Web http://members.aol.com/lwcanews/ Things to be thankful for...The new DX season is upon us, and there are now entire evenings without significant QRN. Many members and non-member beacon operators alike have updated their beacon information promptly, making possible an operator contact list a month earlier than usual. MedFERs will be pleased to note that conflicts over occupancy of the expanded AM band mean another winter without too much QRM there. And I imagine you'll be able to add to this list as well. * A spotless record (figuratively speaking). At this writing, the sun has been more than six weeks without a spot on its face. There were none at all in September, and that trend continued well into October. You may recall that most solar observers believe we reached the solar cycle minimum this summer, when the first spots exhibiting reversed magnetic polarity were observed. However, solar minimum doesn't always coincide precisely with the minimum sunspot counts. At least one researcher, Patrick McIntosh, believes this year's sunspot total will be lower than the minima of the past three cycles. Speaking of the sun, there was a partial solar eclipse in Europe on October 12. I wonder if any of our members there happened to monitor for propagation effects in the lower HF bands, mediumwave, or longwave? If so, we'd be most interested in hearing how your results compared with observations during the annular eclipse of May 10, 1994, in North America. * Deadlines, deadlines. Correspondents ask from time to time about the deadline for this column. Generally, I'm pretty flexible. The column is supposed to be at heaquarters by the second Saturday before the end of the month. As with most LOWDOWN columns, it's best to have typed or handwritten material here before the 12th of each month when possible. However, if the material is particularly timely, I'm willing to put it in the column right up to the last minute. E-mailed material can be processed quicker (at least, as long as you don't use all-capitals in the text), so it's easier to insert at a late date. This month was something of an exception, though. Because of all the database updating, and wanting to make sure the beacon lists are current right at the moment of mailing, I set myself an earlier cutoff for this month's Notebook. This particular column reflects written items received by October 9, and e-mail received by the 13th. Based on the volume of beacon updates that have come in so far, I believe that decision will prove to be a life- saver. Of course, anything that didn't make it into print this month will (barring mishaps) appear next time. Keep sending that news. It's what makes life interesting for all of us. * Web wonders and BBS bulletins. If you've been following the saga of the Longwave Home Page from the beginning, you know that one of the concerns was obtaining enough server space for a decent file library. I don't expect we'll ever have the hundreds of Megabytes available to the Web page that is available to the BBS, but there is good news tonight (as someone used to say on the radio). Discussions are presently underway that could almost triple what's presently available, and there's a chance I might be able to increase my own space enough to almost double it again. The Longwave Home Page now also contains a link to a new Web page by Robert Kramer N9MBK, which presently features mediumwave DX news, and will soon have an area for longwave DX as well. The Longwave BBS will still remain our prime repository of interesting files, so I encourage everyone to continue to use it once in a while. And be sure to register, if you haven't already done so. It really does save time. I do need to mention the new fall schedule for the BBS. It will be available continuously from Friday evening through Wednesday morning each week. As was the case with the summer schedule, it will probably be available other times as well, but these are the times you can pretty much count on it being there for you. (There could be modest interruptions on some Sunday evenings, however. I'll try to have those billboarded on the system ahead of time.) The BBS will probably run full-time beginning about Christmas Eve. HELLO, OLD FRIEND If you didn't happen to be monitoring W1AW on or about October 15, you really needed online access this month to receive some exciting news in time to act on it. I hope some of you were able to do so. It often seems odd to the uninitiated how attached we technical types can get to a piece of supposedly inanimate hardware. Of course, we know that our classic old car, or rare Lionel train, or faithful transmitter, has its own unique personality. So it's only natural to develop a sentimental attachment. And common sense or business necessities be durned, you just don't throw out a friend simply for growing a bit old. Fortunately, there are some folks in Sweden who understand that view, and have preserved a unique piece of radio history. Many longwave enthusiasts have heard of the Alexanderson alternator, the most powerful of the early methods for producing a pure carrier wave for radio communication. However, almost none of us born during or after World War II have ever heard such a transmitter in operation. There's only one operable specimen left in the entire world now...and it was on the air briefly in October. This was the ARRL Bulletin announcing the operation: ARLX018 Oldest LW transmitter The world's only working Alexanderson alternator will broadcast this month from Sweden on 17.2 kHz. A nostalgic Morse code transmission at 0900 UTC on October 23 from station SAQ in Grimeton on Sweden's west coast will commemor- ate the declaration of the radio station as an historic building. The RCA Alexanderson alternator was built in 1924. The SAQ site, complete with six antenna towers and the 200 kW transmitter, are under the care and management of Telia Mobitel, a Swedish mobile telephone company, and the radio museum of the Radio Historical Society of West Sweden, which operates club station SK6RM. Ulf Sjoden, SM6CVE, has helped to organize the event. SAQ also will transmit a test on October 21, at approximately 1100 UTC. SAQ requests listener reports of both the test and the commemorative message via telephone at 46-340-74251 or fax at 46-340-74195. Callers will be reim- bursed for the cost of the call. The operator at SAQ is Bengt Dugaas, who is not a ham. The Alexanderson alternator was developed during the early years of wire- less by Ernst Alexanderson, a Swedish-American. The device is essentially a large, electromechanical high-frequency alternator with a high-speed rotor that's connected directly to an antenna system. A similar station once operated on Long Island. The circuit was used to transmit telegrams and messages between Europe and the US. Last fall, Amateur Radio station 7S6SAQ operated from the SAQ site to celebrate 100 years of radio and the 70th anniversary of the radio station (see ''Up Front,'' QST, Nov 95 , p 14, for a picture of the Alexanderson alternator and the antenna system). During September 1995, SAQ itself trans- mitted a message to England which was relayed via landline from a BBC monitor- ing station to those attending a ''100 Years of Radio'' conference in London. ALOHA, OMEGA Another type of VLF radio facility is coming to the end of its useful life, too. Unfortunately, it may be impossible to preserve a specimen of this one. Greg Greenwood (WB6FZH/KH6, 46-005 Nana Place, Kaneohe, HI 96744; greg6fzh@ aol.com) updates us on the Hawaii OMEGA station: "Latest from Marilyn Kali, State of Hawaii Department of Transportation spokesperson...no Faraday Sheild, and the Coast Guard has verbally advised that September 30,1997, will be the last day of operation of the Kaneohe Transmitter Site. No official written notification has been received yet. NOAA says that they do not have money in their budget to take the site over. The antenna that goes across the valley from the top of the Koolau Mountains will be removed prior to the H3 Highway opening." In unrelated matters, Greg has ordered the Sigma-Delta A/D board, and hopes to start listening for BPSK signals in a few weeks, transmitting later in 1997 with a beacon of his own. And we understand he got married recently, too. Congratulations. ON TO THE MAILBAG -David E. Crawford (decrawf@nersp.nerdc.ufl.edu) starts us off with a mystery this month. "Heard an UNID MedFER here this morning at 1030 UTC on 1687.6, CW, IDing as SAC. Any ideas who/where?" (Alas, I have no information on this one. If you've got a clue, please let both David and myself know. Thanks.) He adds, "We'll try to round up some gear to take a shot at 73 KHz (at the CANAVDX event) and let you know what happens. I found the Brit 73KHz web site via yours, so that should give me an idea what to look for." -John T. Reed (KA5QEP, Oklahoma City, OK; jtreed@juno.com) reports "I was finally able to hear TEXAS, after several years of trying and talking with Bill Bowers. He hears this LowFER almost every day this time of the year, and says it has been coming in real good lately. Today I was able to hear it for the first time. Here's the report: Date: 9/31/96 1830 UTC; Reception: Solid, two IDs followed by long dash; Receiver: CEI R1401, no audio filter, 1 khz bandwidth; Antenna: Bowers ferrite loop on Palomar amp, oriented for lowest noise. Great to finally catch this one!" -And from Texas, comes this word from Bill Cantrell (TEXAS, WD5CVG; e-mail: cantrell_bill@macmail1.fwrdc.rtsg.mot.com): "Good news. The new top- hat for the TEXAS Beacon is now in place! Bill Bowers (OK) has been receiving the TEXAS Beacon lately. I have nearly completed all modifications to the Beacon." "Bill is also logging the signal strength of my beacon on a daily basis. He is comparing changes in signal strength with Station FT on 365 kHz (400W). FT is located about 3 miles from my house. My calculations indicate that FT should be 40 dB stronger than TEXAS (26 dB due to power and 14 dB due to FT freq/tower height at 100ft). I will be trying modifications to the tower and antenna match this Fall to see the effects on radiated efficiency." Your columnist is most impressed with the methodical monitoring, using a "commercial" beacon for comparison. This could probably be beneficial for other experimenters to try. Bill continues, "The top-hat is mounted on nylon insulators so I can try some top-loading experiments too. The top-hat is very heavy-duty. It consists of a steel plate with 8 ball-mount vehicular steel whip antennas, each being 8 feet long, mounted in a radial pattern to the plate. The top- hat has a 9 foot radius. It should improve the radiated efficiency markedly by increasing the antenna current flow at the top of the structure. I also completed rolling out 800 feet of wire netting (chicken-wire) to form the ground-plane. The ground-plane consists of 16 radial spokes 50 feet in length from the tower base." "I used heavy-duty nylon guy wires to support the Rohn 25G tower. One set is at the 25 ft mark and another set is at the top (40 ft). It was a relief to finally get the tower firmly guyed. (I don't like climbing wobbly towers!) The nylon ropes are attached to the metal tower using large glass insulators. This ensures that the guy-rope resistance stays at an extremely high level. That way the nylon ropes will not de-Q the antenna structure as dust and contaminants begin to coat them." "My computer simulations show that the tower voltage should reach about 1,300 VAC peak. Indeed, you can draw a tiny arc to tools or to the ring on your finger by lightly touching the tower metal. I am documenting/ photographing the whole set-up and will submit my findings for a future issue of the LOWDOWN, probably for publication this Spring once the DX season is over. Another nice thing about this investigation is that I have made it one of my college projects for an Antenna Theory class. All classes should be this much fun!" -Dave Holland (DCH, PX; Berlin, MD) reports a good summer this year, following a rough winter that included the passing of his father. Dave credits "a lot of help from my radio friends" in getting through it all. He says MedFER PX is on the air with a reworked transmitter, "and now has a much cleaner signal. It may be off sometimes, so I can use the antenna for other experiments. For now it looks like LowFER DCH will not be on the air this winter. I have other experiments planned for the LF xmitting antenna. I installed some large windows on the south side of my garage workshop, for better light,and sun heating. I'll be able to do more radio work in there this winter." "I am working with Richard Marris, of Slough England, who is setting up a receiving station on the southwest coast of England for winter MF DXing tests. His letter has been in the Lowdown. That's why PX is on early this year." -Cliff Buttschardt (HDO, K7RR; cbuttsch@slonet.org) has been keeping an eye on LF-related messages on the Internet, and recently helped clear up some misunderstandings and misinformation on the subject. Internet message exchanges are fascinating to follow, but hard to convey in print, so I'll just try to summarize. Some time in early October, Brian Carling AF4K (bry@mnsinc.com), responded to someone's query about the LowFER band by saying "In the US it is on 190 kHz. In England it is 73 kHz. Signals generally travel a distance of about 50 feet then disappear! But if you have nothing else to do, why not!" (Well, even over Georgia soil, this is not quite accurate. Down here, we get 100 feet or so before signals disappear.) But Cliff explained the difference between our LowFER band and the British ham assignment, outlined some DX achievements of LowFERs, and directed him to the Longwave Home Page for more information. On October 8, Mr. Carling posted, ""WOW! I apologize and stand corrected Cliff! I had NO IDEA that folks were actually doing that! I HAVE heard some 25 watt LF beacons that far away on my all-band SW receiver (SONY ICF-2010 when I had it), but sheesh with the short antennas and QRPp that hams are using for their transmissions, I am VERY surprised to hear that!!" He later concluded, "Sounds like fun!" Cliff also reports on a new release of the FFTDSP42 graphical digital signal processing program. "This may be another way we can obtain below noise LowFER copy! Bill Lake and I with help from others might be able to see if this idea has merit....As I understand it, a sound card is required----BUT most any resonable sound card will work. Further, I think the readout is graphical which really is not what we want for communications but might prove useful to determine if a LowFER signal is there which can be synthesized to produce intellegence." Mike Cook, AF9Y, stated, "The FFTDSP42 program has been updated to 42t. The only change was to improve the long term display logging and the corresponding playback program. This mode is most useful for recording long periods of unattended operation." FFTDSP42t can be downloaded on the World Wide Web from http://www.webcom.com/af9y or by FTP at ftp.webcom.com/pub/af9y/www and it is also on the Longwave BBS. -Jeff King (WB8WKA; jeff@mich.com) has a track record on LF, and with some new techniques as well. "I am a past LowFER back when I was 13 years old...built the tube transmitter from Popular Electronics. Was wondering if you were aware of anyone using Spread Spectrum on the 160-190 or MF Part 15 bands? Direct Sequence specifically. I am a SS experimentor on 900 and 2.45ghz, and was wondering what type of performence might be expected." Sounds like an interesting area for further experiments. Your columnist would suspect the useful part of 1750 meters is a little skinny for effective spread spectrum work, but who knows? It would seem the Top End might be productive. Anyone have some additional ideas on this? -Lyle E Koehler (LEK, MIN; lek@juno.com) sent a slightly modified version of the article on using an EEPROM in the VE2IQ beacon keyer to Bill Oliver for use in The LOWDOWN. Should be interesting. "My new LF antenna is ready to go up. Initial tests will be on CW using the identifier MIN. By November 1st I hope to have a second beacon running continuously in BPSK mode, on a frequency that is still to be decided. I'll send another short message as soon as the antenna is actually up, with a best guess at the eventual operating frequency. LEK will remain on 186.750 in CW mode." "QRN is slowly letting up. OK is often readable just before sunrise, but I haven't heard any other distant LowFERs so far. SAM is putting in an excellent local signal, and I've also heard ART and RM. On MF, STLMO is still in there pretty consistently and is the only MedFER I've heard since last season." -Brice Anderson (BA, IE) reports that BA has been heard by BOB, but so far not the other way around. Brice has heard YHO, however, beginning with weak reception on October 10, increasing significantly by October 12. Footnote. Much more in the works for next month. Til then, 73. - - -