notebk24.txt THE LF NOTEBOOK The Mailbag, News and Comments About LF Radio & Other Experimental Topics John H. Davis, PO Box 367, Warm Springs, GA 31830 >Fax/Voice: (706) 672-0964 >E-mail: johnhdavis@aol.com >Longwave/Part 15 BBS: 706/672-0360 A wild and wacky winter. What do you make of a DX season where the weather forecast changes every few hours, mostly to add more precipitation? I don't think there has been one week all winter without at least one thunderstorm in Georgia. One early February week was particularly outstanding. Four times in that seven days, we had snow various places in Georgia, including 1-1/2 inches here; severe thunderstorms; fog; humongous winds, northerly and southerly; and flood warnings. (Those get peoples' attention around here now!) The temperature at this QTH one morning was 10º F; a little over 24 hours later, it got up to 70º. I know...that's wimpy compared to some parts of the country, but after all, I moved here to get away from those parts of the country! Between the weather and having to do some serious study of computer programming, there hasn't been much chance to DX this month. But behind every dark cloud, as they say, is a silver lining. The winds make an excellent test of my LF antenna's durability, and so far it has passed with flying colors. Many of the thunderstorms are associated with quick-moving frontal systems, so they sweep off into central Georgia and leave us in clear air. While my mobile whistler listening setup is presently immobile, I still enjoy watching the storms from a distance. Having vantage points on a nearby 500 foot "mountain" enhances such opportunities. One possible tornado producer, over 70 miles away, was extraordinarily visible in its upper regions, and may have produced a couple of "blue jet" upward discharges. Oh, to have a camera with me at all times! A personal note. At this point, if I may, I'd like to take a moment to thank the membership for selecting me for the H. John Clements Memorial Award for 1994. It is a very pleasant thing to have the goodwill of one's colleagues, and to think that they feel one has contributed something useful to the joint effort. There are quite a few members of the organization worthy of this award, who are much more directly involved in the front lines of technical work and serious monitoring than I. When I heard I was "in the running," I expressed concern that I haven't really done that much for the hobby. This column is a high-visibility position; but to paraphrase Will Rogers, all I really know is what you folks tell me each month. I've been tempted several times to say "let's wait a while and see if I ever really do something to justify this." But then I thought of a Garrison Keillor story, the point of which was that if you protest your unworthiness for too long, people will take your word for it even after you finally begin to feel deserving. Therefore, deserving or not, I'm more than delighted to accept this recognition. Thanks to those who voted for me, with special thanks to everyone who has contributed to this column over the past two years. That sort of volunteering and sharing is what really keeps this organization going. Longwave Topics On Line Two items this month should interest members with computers and modems. >For one, the Longwave BBS will go to its temporary spring schedule some time this month. From somewhere in mid-March to about April 21, the BBS will be available from Friday evening through Monday morning. It may be available some evenings during the week (6 or 7 pm to around midnight Eastern), but this will depend entirely on the weather. This is the time of year when we usually have our worst electrical activity here, and since I will probably be unavailable to disconnect the phone lines in time, this is the best way to minimize risk of damage and extensive downtime. During this schedule, you may also find only 2400 baud available for extended periods, due to noisy phone lines. If so, set your modem to 2400, rather than depending on it to fall back to the right rate; it appears some high speed modems may not turn off multi-carrier demodulation, and are still susceptible to noise. We continue to expand the available files--which, in addition to latest beacon news and electronics programs, now also include a few radio-related science topics, items about Space Shuttle missions, and some helpful utilities for users of PC-compatible computers. The focus is still on longwave, Part 15 operation, and related experimental activities, of course. If you haven't tried it yet, sign up for Sprint's 10 cents per minute plan or some other long distance money-saver, and get on-line! > The other exciting "interactive" news comes from Tim Brannon: "I have checked into the CompuServe HAMNET several times over the last few weeks, and I just want to let everyone know that there is a healthy amount of interest in LF/VLF/Lowfer activities there from people who see the occasional magazine article mentioning LF/VLF listening and Lowfer activities. Most of these people are seeking more information and are not LWCA members. The current message threads are the WEAK/EXOTIC signals message section. Any other LWCA members who are on CompuServe should be sure to check in and throw in their experiences! The hourly rates for CompuServe have recently dropped again, down to $4.80/hour for 300 through 14,400 baud." Tim can be reached via CompuServe e-mail, or through the Internet. His address is: 76546.1311@compuserve.com. DX Partyline Update Comments have been favorable toward the idea, mentioned in January, of the LWCA participating in a monthly segment on HCJB's "DX Partyline" program. It is therefore being pursued (albeit a tad slowly), and your columnist will be contacting the producer again soon. This may or may not be a current schedule for the program: UTC Day Program Block Freq. & Target Area 0109 Sun 0030-0159 9.745 12.005 17.490 (Am) 0509 Sun 0500-0559 9.745 (Am) 0739 Sat 0700-0830 9.420 (Eu) 1009 Sat 1000-1125 6.135 9.745 (Pac) 1709 Sat 1700-1759 15.490 (Eu) The Mailbag for March >There were a number of new LowFERs and changes to existing beacons reported since last month's listing. One of these, OVO/N3, belongs to new member John Graham (PO Box 255, Bunola, PA 15020). John is also a ham, and can be reached on packet: N3OVO @ W3CSL.SWPA.PA.USA.NOAM. >Robert Laney (RL, WB7PZU, 3153 Southfield Drive, Herndon, VA 22071) has beacon RL operating on 188.59 kHz. This was listed as the alternate frequency last time. "I abandoned the original frequency of 186.59 because of inter- mittent QRM from an unknown source. Will be interested if anyone is copying the signal." > David Oliver (WB6VKH, 5930 Deary Way, Orangevale, CA 95662) is a new visitor to the Longwave BBS and a recent LF enthusiast: "I've just started up a VLF station and wish to learn more about (LF)." We'll try to find out more about his operation next time. David adds: "For those who have the MFJ-259 analyzer, I have a mod which I've completed on mine, which changes the range from 1.8 MHz - 170 MHz to cover the VLF band. After conversion the analyzer covers 100 kHz to 170 MHz. I just had to do it in order to make the VLF antennas tune better. If anyone is interested in how to do the modification, drop me a line and I'll send you some stuff." > Robert J. Fear (IA; 225 North Boots, Marion, Indiana 46952) sends compliments to all the authors who make the Lowdown such an interesting publication. Robert is a new beacon operator now. "My transmitter is active as IA. Operation is CW, 24 hours a day, on 184.32 kHz. The antenna and tuner are a miserable failure. Some additional work should boost the radiated signal strength." "I recently built an up-convertor for 10 kHz to 550 kHz to feed a modified AM broadcast radio. The convertor in combination with a tuned loop antenna are giving wonderful results except for a dirty carrier comming from a local low-power AM Broadcast station at (400 kHz) 1400 kHz. At first I thought it was bad grounding on my part, but after borrowing a spectrum analyzer I could see the problem in the vivid green glow of the CRT....All I really want is a tunable tranceiver and antenna with a frequency range of 0 kHz to blue light. "Some interesting things have happened as a result of my long-wave work: "(1. My wife thinks I'm crazy. According to her I spend far too much time at night listening to 'all that noise'. I think she'll catch on eventually. "(2. My neighbors are starting to wonder if I'm attempting to contact aliens. I got some very strange looks while putting up my receiving loop and rotor. "(3. My oldest daughter is starting to take an interest. She has spent some time recording and decoding beacon call signs. "In closing I would just like to say that I never expected to find anything between 10 and 500 kHz let alone such a dedicated group." > Congratulations to recently-renewing member LeRoy E. Anderson (Crystal Falls, MI) on acquiring his Technician license, call sign N8WQG. He's working on getting his General ticket next. > Another recent renewal is from Joseph J. Rein, Jr. (Two Dogwood Road, Netcong, NJ 07857). Joseph has been with us off and on since the days when the Lowdown was a self-addressed-stamped-envelope newsletter. He receives TH consistently, day and night, during the low temperature seasons, but mainly concentrates on NDBs, particularly those operating 25 watts or less. > Bruce Koehler (BK; Shell Lake, WI/Maplewood, MN) recently signed up for membership, and has been using his beacon for practical purposes. On weekdays, it sends weather information from the Shell Lake cabin; specifically, wind velocity and crawl space temperature. On weekends, he and LEK exchange messages during the day in CW at 12 - 15 wpm. The wind speed comes from an 8-foot ornamental windmill. Temperature data may soon include indoor and outdoor temperatures as well. He says a typical message reads something like this: DE BK BK BK CRAWL TEMP 45 WIND 12 = Very handy. > Dave Sampson (117 Briarcliffe Road, Dewitt, NY 13214) hasn't had any luck finding a new home for his WW II Navy regenerative LF receiver and power supply, described as working and in beautiful shape cosmetically, so he's ready to "sweeten the deal" with an RME VHF-152A 2/6/10 meter converter (with manual) and a Conar 220 tube tester. Still $100 on a pick-up basis. Call 315-446-1258 after 7:30, or leave a message on his answering machine. > John Lyman (TAL, Tacoma, WA) advises that anyone interested in contact- ing him about TAL can now do so via Prodigy. "Our info is listed under 'Linda', not John Lyman, ID# QBMH71A. In a few days I will have our new fax line up too. That will be the same as my home number. I will be able to receive faxes from 1pm to 6pm pacific time (longer hours later)." > David Jones (Columbus, GA) has been taking advantage of the Georgia winter thunderstorms that have been such a plague on LowFER and MedFER operation. They provide him with some excellent whistler monitoring opportunities. One example, from his January 29 note: "Heard dozens of whistlers last night. Was trying out a mobile antenna , which failed in the wind. Two thunderstorms persisted for several hours so I recorded until out of tape." A rural area about 25 miles south of the Columbus/Ft. Benning area provides sufficient quiet, QRM-wise. A trip to hunt Litz wire on February 5 gave David a similar opportunity. He was able to hear quite a few whistlers with his mobile setup, along with JDH. He used his mobile gear a few weeks ago to plot reception of SEA in the vicinity of my QTH (an effort which, I'm embarrassed to say, demonstrated the shielding effect of the pine trees near the present antenna). > John Reed (Ponca City, OK) throws some light on a misperception that I inadvertently expounded last time about the Watkins-Johnson DSP receiver. He addresses the matter of dynamic range thus: "I did quite a bit of research on dynamic range for various receivers. I have enough test equipment to make measurements of it when it's not too high, and to the best of my knowledge, the HF-1000 has a very good dynamic range. Here are some measurements that I pulled out of my collection of RDI White Papers on various receivers: Receiver 20 Khz TOIP 5 Khz TOIP --------- ----------- ---------- ICOM IC-R71A +5 dBm (Excellent) -19 dBm (Excellent) NRD-525 +5 dBm (Excellent) -24 dBm (Good) NRD-535 Noise limited -20 -35 (Good) NRD-93 ($7000) 0 dBm (Excellent) -46 dBm (Fair) Drake R-8 +7 dBm (Excellent) -21 dBm (Good) ICOM IC-R9000 ($5500) -9 dBm (Good) -33 dBm (Fair) Kenwood R-5000 -2 dBm (Good) -34 dBm (Fair) W-J HF-1000 ($3800) Superb (> +10 dBm) Excellent "The last rating is a preliminary one from a review in Passport to World Band Radio, 1995 edition, done by the same group that publishes the White Papers. In the Passport review, the following statement concerning dynamic range is made: 'And the radio's dynamic range is classic Watkins-Johnson: superb at 20 Khz seperation, excellent in the tougher 5 KHz test.' There was also a review of the HF-1000 in QST recently. They got a dynamic range of +27 dBm at 100 KHz spacing. Here is a statement about the front end of the HF-1000 from that review: 'the HF-1000 uses a DMOS FET switching mixer. It's about time we saw this high-dynamic-range technique in a receiver that's within reach of consumers.' My own experience with the receiver is that I have yet to hear an example of inter- or cross-modulation on it. I don't have the optional preselector." "The HF-1000 is not the perfect receiver yet. There are some software glitches (the latest version 4.01.01 will be sent out soon, free to owners) and the set radiates some noise. Watkins-Johnson has a fix for this, also to be released soon. I'm real happy with the receiver, and especially the interaction with Watkins-Johnson customer service. This is the second free upgrade of software they have furnished. More upgrades are in the works." John's comments certainly constitute a hearty endorsement. What I read was probably referring to the dynamic range of the A/D conversion (e.g., the number of bits used)--not the RF dynamic range, which is evidently quite good. I wish I could recollect the source for that notion. It might clarify things further. The more bits used in the digital section, the greater the precision of the math that can be performed, and thus the more accurately the filtering and demodulation algorithms can be implemented. However, that wouldn't have any effect on the RF dynamic range, which is what most of us think of when it comes to dynamic range in receivers. So, please excuse your columnist's presumptuous assumptions on the subject. Footnotes. We do have a couple of other notes I'd like to include this time, but it is fortunate that they are not time-sensitive. Severe storms overnight resulted in some problems at the TV station which I must now deal with. (No consequences at home yet this month, for which I am grateful.) They will give us a head start on next month's column, but we need your news, too! Enjoy what remains of this season. Let us hear how your efforts go, and as always, please advise if your schedule will be changing in April. Til next month, 73. . . .