Past Longwave Messages

Past Longwave Messages - July 2000

(For the next few months, you will notice a difference in the format of these archives. We had just converted to the new Message Board and were testing different ways of archiving each month. We hope this will prove satisfactory in the long run, but we apologize that this page does not meet our usual standards. Your comments, as always, are welcome.)

Addresses and URLs may become outdated over time.

SAQ reception

Posted by Michael Oexner michael.oexner spksuew.ron.de on July 03, 2000 at 08:07:05:

Hi all, Sunday's 1245 UTC transmission of SAQ was received quite well here in the southwestern part of Germany. My listening equipment consisted of a surplus Selective Level Meter SPM-3 by Wandel & Goltermann, and a simple longwire antenna of 20m length. Seems that the transmissions that were scheduled for 0830 UTC and 0845 UTC did not take place. vy 73 + gd DX, Michael RX: ICOM R71A, Sony ICF-SW7600G, W&G SPM-3 Antenna: Radio West 22.5" ferrite loop with amplifier, 20m longwire, Wellbrook ALA 100 Location: Roschbach, Germany N 49°15' E 8°07' Member: CSDXC, DSWCI, EUNL, LWCA, MWC Editor of "The European NDB Handbook" e-mail: michael.oexner spksuew.ron.de

Posted by Bill Ashlock ashlockw hotmail.com on July 04, 2000 at 03:09:04:

In Reply to: SAQ reception 57 posted by Michael Oexner on July 03, 2000 at 08:07:05:

Reception of SAQ in Andover, MA. was fairly strong 4-6db above backgrond noise. The signal remained essentially constant over the hour and 15 min of broadcast time beginning at ~1243 UT. Equipment: 3.5 ft balanced loop with FET preamp feeding simple NE-602 up-converter to lowfer receiver.

Posted by Frank H. Reynolds reynoldsf rl.af.mil on July 03, 2000 at 09:29:07:

In Reply to: SAQ reception 57 posted by Michael Oexner on July 03, 2000 at 08:07:05:

Reception in the middle of New York state was very noisy. Very few moments of clear CW. I will have to use DSP to clean up the signal. Equipment: Drake R8A, Palomar VLF-S Upverter, approx. 100 meter long wire.

Posted by Sandy Sanders esanders erols.com on July 04, 2000 at 23:14:39:

In Reply to: Re: SAQ reception 58 posted by Frank H. Reynolds on July 03, 2000 at 09:29:07:

Reception also very noisy 60 miles West of Washington DC. Parts of the message were copied on a Cubic R-3080 connected to a tuned FET preamp connected to 40 foot whip and a RBA-1 ( 1942 ) hooked to 1000 feet of wire run along the ridge top. The R-320, 6 foot E-field probe, laptop combo did not receive the signal at all even though it picked up GBH on 16 Khz ok. We are still trying to figure that out. Sandy WB5MMB

Web version of synthesized LowFER transmitter article

Posted by Lyle Koehler lyle mlecmn.net on July 03, 2000 at 12:03:23:

I have posted an Internet version of the "all-in-one" BPSK/CW transmitter construction article on my web site. It may be a little easier to decipher the circuit layout from the color pictures on the web, as opposed to the black-and-white reproductions in the July LOWDOWN.

Posted by jim vander maaten james.vandermaaten sanmina.com on July 05, 2000 at 13:38:24:

In Reply to: Web version of synthesized LowFER transmitter article 59 posted by Lyle Koehler on July 03, 2000 at 12:03:23:

Where may I find it? 73 Jim

Posted by Lyle Koehler lyle mlecmn.net on July 05, 2000 at 19:21:54:

In Reply to: Re: Web version of synthesized LowFER transmitter article 64 posted by jim vander maaten on July 05, 2000 at 13:38:24:

Sorry about that. I failed to include my web address in the original posting. My web site is http://www.computerpro.com/~lyle/

The direct link to the synthesized transmitter is http://www.computerpro.com/~lyle/all-in-one/all-in-1.htm

Back Issues of Lowdown?

Posted by Les Rayburn les highnoonfilm.com on July 03, 2000 at 16:32:08:

I recently purchased back issue copies of the last two years worth of the Lowdown, and then realized that I really needed to go back futher. Does anyone know how many back issues are available? What is the cost of back issues? Les Rayburn, KT4OZ

Posted by John Davis on July 04, 2000 at 18:41:01:

In Reply to: Back Issues of Lowdown? 60 posted by Les Rayburn on July 03, 2000 at 16:32:08:

Back issues of The LOWDOWN are (or have been) available nearly all the way back to the beginning of the LWCA. (Not all are available all the time.) As indicated in the subscription links on our home page, the publisher is the one who can quote prices, as this varies by size of the issue and by whether the available copies are from the original press run or are photocopy reprints. Write Bill Oliver at the headquarters address or boliver at bboard.com and specify which issues are of interest. 73, John

Lowfer Documentary

Posted by Les Rayburn, KT4OZ les highnoonfilm.com on July 07, 2000 at 08:51:36:

Just to update everyone on the upcoming Lowfer video, we've got good news! We will be receiving publicity in upcoming issues of both the Lowdown and Monitoring Times. This will delay the release of the video until early this winter, but will allow us to get more beacon operators to participate by sending in videotapes of their shacks. We have also received support from Curry Communications and LF Engineering. We'll be including "video reviews" of their products. We've contacted other companies who make products of intrest to the LF community as well. Such as Kiwa who makes a low pass filter to reject BCB signals. Videos and photos are starting to trickle in too. Inclduing some from the West Coast. PLEASE SEND IN YOUR VIDEO AND/OR PHOTOS! Again, all we need are camcorder videotapes (any format) of your station. Please use a tripod if available. Hold the shots steady for at least 10-30 seconds...and show us around! We need shots of the antenna, ground system, transmitter, loading coil, receiver, loops, active whips, any homebrew items, and at least one shot of you! Please send them to: Les Rayburn, KT4OZ 4919 Cox Cove Helena, AL 35080

Curry Comms LF Xcvr

Posted by Keith Ballinger kballinger idirect.com on July 10, 2000 at 12:26:10:

Has anyone looked into what modifications are needed to make the Curry 1750 meter transceiver work on 136kHz?

Vanity Call

Posted by Les Rayburn, N1LF les highnoonfilm.com on July 11, 2000 at 01:16:03:

Just wanted to post a little "brag" about my new vanity call. I asked for and received my first choice, N1LF. I'll be putting a new remote lowfer beacon on the air soon in Cleveland, TN. The call will be "1LF". XMGR will remain on from the home QTH. Sorry, just excited about the new call. Les Rayburn, N1LF

Posted by Geri, DK8KW (W1KW) on July 22, 2000 at 03:48:22:

In Reply to: Vanity Call 68 posted by Les Rayburn, N1LF on July 11, 2000 at 01:16:03:

Sorry, just excited about the new call ....

Les, I know how you feel ... congrats on the "LF" suffix ...

73 Geri, DK8KW (W1KW)

VLF/LF homepage http://www.qru.de

Re query on Taiwan beacons

Posted by Mike Troy, CA Carmelink aol.com on July 13, 2000 at 10:40:11:

Mark had asked about a list of UNIDs he hears in Taiwan. Here's my best guesses, which he'll have to verify with DFing: MS 224 Ilan (was 435) BM 290 Makung HKG 338 Hong Kong (Cape D'Aguilar) BS 345 Quemoy HL 360 ? maybe ex CC,Cheung Chau, Hong Kong NN 375 Tainan (was 235) YU 380 Hualien (was 230) MD 405 ? maybe ex SC,Stonecutters,Hong Kong KW 415 Hengchun KU 525 Chia-I (was 365)

Xmitting Loop

Posted by Bill Ashlock william.ashlock edwards.boc.com on July 14, 2000 at 00:12:21:

I have decided to shut down WA 185.200 for a about a week to give me time to work on some new findings. I have constructed a 4'x4'x12 turn transmitting test loop that surprisingly appears to match the prevailing math for signal strength in the Lowfer band including area, current, and number of turns with no apparent ground losses. Experiments on my regular 50'x50' loop last fall indicated a decrease in signal with increased number of turns but I am now thinking that this could have been due to inadequate spacing of the turns rather than due an increase in ground losses. A couple of other discoveries with the test loop are: a) Far lower ground losses in terms of loop Q than originally assumed. I have obtained a Q of 360 with the lower leg only 8" above and parallel to the ground. b) A 3db stronger signal in the far field when the loop is located over a buried ground network rather than over bare ground. I would be interested in comparing notes with anyone that has experimented with multi-turn transmitting loops at or near the Lowfer band.

Airnav missing HP 281?

Posted by Mike Troy, CA Carmelink aol.com on July 15, 2000 at 07:51:03:

HP 281 khz, 5 mi out from Runway 16 of HPN,Westchester County, NY. Still on the air but not found in Airnav.

Posted by Jacques d'Avignon monitor rac.ca on July 15, 2000 at 12:01:39:

In Reply to: Airnav missing HP 281? 71 posted by Mike Troy, CA on July 15, 2000 at 07:51:03:

I have ben told that many LOM beacons across the USA do not appear in the particular dbase. Does anyone know where to dload the latest up to date FAA dbase of the various USA LW beacons and navaids

Posted by Dave Tomasko kdtomasko aol.com on July 15, 2000 at 12:32:07:

In Reply to: Re: Airnav missing HP 281? 72 posted by Jacques d'Avignon on July 15, 2000 at 12:01:39:

Many can be found (albeit painfully) in the Aircraft Owners and Pilots Association (AOPA) directory. Other good sources are Monty's Beacon Guide [now out of print] and Kevin Carey's Beaconfinder

Frequency Selective Voltmeter, modifications

Posted by Frank J. Lotito k3dz aol.com on July 16, 2000 at 08:26:13:

Any one with info on the Sierra-Philco Ford Frequency Selective Voltmeter, Model 126B? I do have a clean copy of the manual, and for years I've owned a Model 126B. I am specifically looking for info on modifications to "improve" this model's (or a similar models') performance for use as a LF / VLF receiver. 73's Frank lotito, K3DZ

Whistler Storm!

Posted by Mark Karney naturalradio norwest.net on July 17, 2000 at 09:53:51:

The solar flare of July 14 and the associated geomagnetic storm of July 15th and 16th produced quite a whistler storm here in Illinois. On Saturday evening about 10:30 local time, I was hearing loud diffuse whislters at the rate of about 3 or four a minute. Around there was a background of hissy whistlers fading in and out along with chorus, risers, and various other birdlike sounds. Unfortunately, sferics were strong throughout the whole period also making listening difficult. I was still hearing whistlers at the rate of one or two per minute when I quit listening at 10 am on Sunday. There's still time to get your whistler reports in for the August issue of The Lowdown, I would need them by Friday, July 21. I would love to hear if other Natural Radio listeners had good results during the storm.

Posted by Jim Hardy jahardy33 hotmail.com on July 27, 2000 at 21:22:37:

In Reply to: Whistler Storm! 75 posted by Mark Karney on July 17, 2000 at 09:53:51:

I hooked up to a tree and ground during that time and had a lot of cliks and chorous but no whistlers yet. I am going to try the woods out by Fermilab and see if that makes a difference. What kind of location are you in? Mine is a golf course. Thanks. Are you near Naperville? Jim

Posted by Mark Karney Naturalradio norwest.net on August 07, 2000 at 13:59:13:

In Reply to: Re: Whistler Storm! 86 posted by Jim Hardy on July 27, 2000 at 21:22:37:

Hi Jim, I am up in Barrington. I tried a few locations around town. In the locations with trees, I didn't hear any whistlers or chorus. What kind of receiver are you using?

Posted by Jim Hardy jahardy33 hotmail.com on August 11, 2000 at 21:58:50:

In Reply to: Re: Whistler Storm! 106 posted by Mark Karney on August 07, 2000 at 13:59:13:

Hi: I have a LF Engineering L500 and hooked it up to a tree for listining. No good antenna yet. Hoping to build a loop about a meter across and 25 interconnected turns. I am wondering if I shouldnt put a 365 variable across the thing for tuning. I have a high pass filter for Broadcast band. I get a lot of sferics here in Naperville. and the Ionospheric changes during the day. Jim

Posted by Mark Karney naturalradio norwest.net on August 22, 2000 at 11:02:41:

In Reply to: Re: Whistler Storm! 110 posted by Jim Hardy on August 11, 2000 at 21:58:50:

I haven't tried trees as an antenna although I have heard that it does work. I'm not real familiar with the LF-500, but I think I would try it wit a 25 or 30 foot piece of wire out in the open, well away from tress and other obstructions. As far as the loop goes, I think a 1 meter loop with 25 turns and a 365 pf capacitor would resonate at about 300 kHz. This is way too high for natural radio listening. I have the loop receiver from LF engineering and the loop has a pretty large capacitor across it. However, a resonant loop has a very high Q and thus a very small bandwidth which is not suitable for whistler listening. I haven't looked at the front-end design of the LF engineering receiver to see if they are loading the loop to reduce the Q, although this might be a neat way to roll of the response to hum and LF beacons and broadcast stations.

XMGR Update

Posted by Les Rayburn, N1LF les highnoonfilm.com on July 18, 2000 at 14:49:21:

Complete details on the XMGR update have been posted on our website: http://www.highnoonfilm.com/xmgr In summary, I've completed the construction of the new antenna. It is a "flattop" vertical very similar to the type used by NDB beacons. The vertical section is up to 40 feet and the tophat runs 70 feet in the horizontal direction. The transmitter and loading coil are mounted in a weatherproof enclosure mounted above an 80 foot radius elevated counterpoise ground system. I am installing a total of 32 radials, most of which will be terminated on the chain link fence that surrounds the backyard. This fence is grounded and bonded to several 10 foot copper rods at various points. The beacon has also moved to 186.404 Khz. Unless there is a good reason to move, we'll stay at this frequency for the coming season. (This is the "old" frequency for the beacon when it was on the air ten years ago) We have also posted a listing of lowfers in the Central and Eastern US. We are starting to list "indicators" of NDB beacons that are nearby these lowfer beacons to check propagation. For instance, NDB beacon "BEQ" is a 25 watt beacon on 368Khz, located 4 miles from my QTH. If you can't hear this 25 watt beacon on any given night, my 1 watt signal is not likely to make the trip (at least not on CW) The next phase involves hooking it up the LF anaylzer and getting some hard data on the antenna. After that we'll be installing the new CW/BPSK transmitter. Whew! Please do send in your own "indicator" information so that I can post that to the listing. Also, we need video tapes and/or photographs for the documentary. Bill "TEXAS" shot over 30 minutes of footage of his set-up that promises to be incredible! Can't wait to see more from the rest of you! Les Rayburn, N1LF (XMGR) 4919 Cox Cove Helena, AL 35080

NDB DS 344 KHz Des Moines, IA still on the air

Posted by Tom Doc Gruis, K0HTF and LW D donnatom netins.net, K0HTF aol.com on July 19, 2000 at 08:27:24:

19 July, 2000 Greetings from Iowa. I have noticed that Des Moines, Iowa, USA NDB DS -.. ... is not listed on the usual lists and search systems. It is still on the air on 344 KHz. The transmitter is located SE of Des Moines (EN31) and a marker beacon shares the site. The antenna is a flat top that is by far mostly the flat top! The vertical portion in probably about ten feet. I'll check and see if I can find co-ordinates for it. But the following, from AirNav.com will be close: "Lat/Long: 41-32-05.759N / 093-39-38.456W (41.5349331 / -93.6606822) (estimated) Elevation: 957 ft. / 291.7 m (surveyed) Variation: 04E (1990) From city: 3 miles SW of DES MOINES, IA" ---- actually SW of downtown; it is is the city limits. TG 73! Tom "Doc" Gruis, K0HTF and LW "D"

LowFER transmitter corrections; cheap custom "crystals"

Posted by Lyle Koehler lyle mlecmn.net on July 19, 2000 at 11:42:40:

In trying to order parts for the synthesized LowFER transmitter described on my web page and in the July LOWDOWN, I discovered two problems. First, the RadioShack.com BCD DIP switch (RS part number 900-5870) that is shown on the parts list has a completely different pinout than the Digi-Key switch (No. SW216) I used in the prototype. There is no easy modification to the circuit board that will allow substitution of the Radio Shack switch. Second, AMP has discontinued the surface mount DIP sockets and they are no longer stocked by either Digi-Key or Mouser. Acceptable substitutes are the inexpensive leaf-spring type of IC sockets, but you have to use a needle nose pliers or other type of tool to bend the pins into an "L" shape. High-quality sockets with machined pins won't work because you can't bend the pins at all. Suggested sockets are the RadioShack.com No. 900-5745 (28 pin); 900-5740 (16 pin); 900-5739 (14 pin) and 900-5744 (24 pin). Of course, another alternative is to dispense with the IC sockets and bend the IC pins for direct soldering to the PC board. Sorry about the inconvenience to anyone who has attempted to build the project. For those who don't need a full-blown synthesized BPSK/CW transmitter, there is now an inexpensive source of custom "crystal" oscillators. Digi-Key stocks the Epson line of programmable oscillators. They apparently use some kind of PLL technology to generate any frequency between 1 and 125 MHz. You specify which package option (surface mount, 8-pin or 14-pin DIP) and what frequency you want. A gal at Digi-Key programs them and they are shipped the same day. Stick them on a protoboard, apply 5 volts, and you get a 5 volt p-p square wave at your specified frequency, within 50 parts per million. (Much better than that over a limited temperature range.) Of course anything that exotic commands a premium price -- $3.33 each in lots of one. I ordered a couple of them to play with; one at about 1.7 MHz and one in the 18 MHz range. Judging from a few quick tests, they seem entirely acceptable for LowFER (with an appropriate binary or decimal divider to get down to the right frequency range) or MedFER transmitters. They may be acceptable also for QRP HF transmitters, although the phase noise seemed too high for use in an HF receiver application. I'll post some additional information to the LWCA message board and the LowFER reflector soon.

RADIO WAVES below 22 kHz

Posted by Renato ROMERO, IK1QFK openlab vlf.it on July 19, 2000 at 18:40:28:

The web site in subject has moved at new URL: www.vlf.it A new interesting session on the Alpha station, by Trond Jacobsen, has been added. Thanks for the collaborations. Bye, Renato.

137 kHz QSO

Posted by Mitch VE3OT PowellM claven.fanshawec.on.ca on July 22, 2000 at 18:09:57:

Good day lowfers: Poor to medium conditions, but at 1400 GMT - July 22, VA3LK and VE3OT accomplished first 2-way QSO on 136 kHz - a first in Canada. The distance was 431 kM (268 miles). Method was with QRSS, using the sweep second hand to count the dots and dashes ! VA3LK - using IRF540 final ( 18V 4A) and with 270 ft tower. VE3OT - G0MRF rig (at 200 watts) 50 foot marconi with 80 ft tophat. VA3LK 44:40N 76:25W and VE3OT 43N 81:15W (London, ON) Great relief to finally make it, and makes all efforts worthwhile. Will progress now to improving antennas and "tweaking" the systems. Many thanks to all who advised, consulted and encouraged us with this project. Lyle, K0LR was instrumental in helping me initially learn how to tune the antenna. Lots of rf burns later, and it works ! 73 Mitch VE3OT

Posted by Les Rayburn, N1LF les highnoonfilm.com on July 26, 2000 at 13:09:55:

In Reply to: 137 kHz QSO 81 posted by Mitch VE3OT on July 22, 2000 at 18:09:57:

Congradulations! Those of us in the "lower 48" sure envy you!

Posted by Keith Ballinger VA3QF kballinger polyphaser.com on July 25, 2000 at 16:34:38:

In Reply to: 137 kHz QSO 81 posted by Mitch VE3OT on July 22, 2000 at 18:09:57:

Congratulations to you both on the first legal 136kHz QSO! I am looking forward to hearing of the formal release of this band in Canada in the not-too-distant future.

Epson programmable crystal oscillators

Posted by Lyle Koehler lyle mlecmn.net on July 23, 2000 at 18:44:22:

I've added a brief test report on the Epson programmable crystal oscillators to my web page. The report can be accessed directly at http://www.computerpro.com/~lyle/epson/epson.htm

XMGR Counterpoise Test

Posted by Les Rayburn, N1LF les highnoonfilm.com on July 25, 2000 at 13:07:17:

Last night I stayed up late and completed the "doghouse" to house the transmitter, loading coil, and variometer. Early this morning, I got permission from my XYL to attach 16 elevated counterpoise radials for a "one day test" of the entire system. The antenna is as follows: Ground: 16 radial elevated counterpoise. Mounted approximately 4.5 feet off the ground. All radials connect to a chain link fence which is bonded and grounded every ten feet with copper ground rods. The radials vary from as short as 25 feet to as long as 80 feet. All radials are soldered to a 1 inch copper tube that is mounted at the base of the "doghouse" (which is mounted on a wooden pole) Vertical: The vertical section is a #14 gauge wire that runs 40 up (appox. 35 feet above the counterpoise) Tophat: The tophat is a three wire flattop made of copper wire. It is 3 feet across, with a 1 foot spacing between the wires. Approx. 300pf. Loading coil: I am using a tapped litz wire coil (wound by Bill Bowers) in series with a surplus LF variometer made by Atwater Kent. The variometer is "nudged" using a long wooden dowel. The "Q" of this combination is approx. 400. Did not have time to test everything with the LF analyzer yet but my RF current meter read just a hair over 210ma of antenna current this morning, running .97 watt input. Not bad at all! Listened to the signal at my office at a distance of about 12 miles; big improvement. Competes nicely with NDB BEQ located just 4 miles from my home, that runs 25 watts. This signal is easily 12db better than my original antenna. ------------------------------------------------------------------------------------------ Comparison to original monopole: My original antenna used an insulated 40 foot antenna with a large radius tophat. Tophat capacitance was measured at over 600pf, and the ground system consisted of approx. 200 feet of buried chicken wire, along with many long radials terminated in ground rods. I also had sunk five long copper ground rods directly at the base of the antenna. The main problem with this antenna was that it was mounted directly next to the house and was base loaded. Losses due to coupling were huge. Signal was only barely readable at my office and antenna current never rose above about 150ma or so. I think the improvements are due mainly to getting the vertical section in the middle of the back yard and further away from objects that it could couple energy into. Also, the counterpoise is hard to beat when it comes to reducing ground losses. A slight improvement is also due to using the variometer instead of a air capacitor for fine tuning. ------------------------------------------------------------------------------------------------ Future Plans (Winter season, 2000) My first order of business is to race home today and do measurements before my wife gets home. Then I'll have to coil up the radials until we can stop mowing, swimming in the pool, etc. After the pool is closed, I plan to put up at least 32 elevated radials, perhaps even 64. I may also try to spread the tophat wires out to 10 feet across, if I can find suitable spreaders. I will also swap out the CW only transmitter for a CW/BPSK transmitter before the start of the season. While no lowfer beacon is ever "complete", I think this one is 90% there and ready for operation this coming season. I really need to thank Lyle Koehler, who has served as my "virtual elmer" answering over 100 e-mails from me since April. Also, Bill Bowers who has supported me even longer, and been incredibly kind. Thanks to all who've helped out with advice, gifts, and time. All of it is really appreciated. Come on Winter!!! Les Rayburn, N1LF XMGR 186.404khz

loop antennas

Posted by chris steele rm3squid aol.com on July 29, 2000 at 19:16:32:

looking for someone that can help me figure how to design a loop antenna for longwave with materials that i have around the house

Follow Ups: Re: loop antennas 105 Frank J. Lotito 8/07/2000 (0) Re: loop antennas 91 Lyle Koehler 7/31/2000 (0) Re: loop antennas 88 Mick Reed 7/30/2000 (2) construction 97 chris steele 8/02/2000 (1) Re: construction 103 Mick Reed 8/06/2000 (0)

Posted by Frank J. Lotito k3dz aol.com on August 07, 2000 at 13:42:17: In Reply to: loop antennas 87 posted by chris steele on July 29, 2000 at 19:16:32:

Chris - A decent, though dated source for formulas that can be used to determine the inductance of different geometry (shape) loops suitable for LF receiving antennas is "Princilpes Of Communication," J. H. Morecroft, third edition, John Wiley and Sons, NY, 1933. The second and first editions of the same book may also help. See if your local library can borrow this title via your state's inter-library loan program. GL, 73's Frank J. Lotito

Posted by Lyle Koehler lyle mlecmn.net on July 31, 2000 at 10:34:52:

In Reply to: loop antennas 87 posted by chris steele on July 29, 2000 at 19:16:32:

A useful tool for designing receiving loops is Reg Edwards' RJELOOP3.EXE software, downloadable free from http://www.btinternet.com/~g4fgq.regp/ My web site at http://www.computerpro.com/~lyle also has information on LF loops and preamps.

Posted by Mick Reed bossmonkey juno.com on July 30, 2000 at 15:20:25:

In Reply to: loop antennas 87 posted by chris steele on July 29, 2000 at 19:16:32:

You can build a useable coil with sruff in the home, but be aware that it may not be as sturdy, weatherproof, etc. I don't know enough to actually design the coil with you, but here's some ideas for materials. You need three things to build the loop: 1. Wire 2. a Form to build the coil on 3. a Tuning Capacitor to tune the antenna to resonance. Wire You can find wire in several places in the home. Most of the coils I have read about use fairly thick wire, between 20 and 14 guage. However, smaller wire will work too. Kids' motorized toys which are broken can be dismantled for the magnet wire found in the motors. The solid type telephone wire can be used, you will find this in the wall connecting a phone outlet to the outside telephone box. An unused telephone outled could be removed and wire gotten from there. Also, speaker wire which is unused can be used for loop forms that don't require solid wire. Also in the home you may have extra coaxial cable. Loops can be constructed from that, too. You can definitely use any spare house wire if you are lucky enough to have it. This wire is solid and usually 14 or 12 guage. Form In the home, you can find things to make a form from. If you want to make a cross-type form which is pretty popular, try: wooden closet rods floor mouldings which are hidden behind furniture broomsticks/mop handles In an apartement, where you have really limited room, how about a loop that is wound around the perimiter of a closet or cabinet door? The door can be opened to different angles to listen in different directions. Of course, this is not a great choice, but it is there. For the type of coils made inside plastic tubing: The tubing is a great, but without it, you could still have a cheap useable coil. Simply find something else to wind the coil on (garbage can lid, laundry basket, etc.) and use something to hold it together (tape, plastic wire ties, twine, string, etc.). Tuning Capacitor Find an old AM/FM or AM radio that you don't use anymore or that is broken. If you don't have this, you can find them pretty cheap at the usual budget sources. Again, these are not preferred construction techniques, but for a budget coil, okay.

LowFER transistors or Xmitter schematics?

Posted by Shane Passmore aa5te aol.com on July 31, 2000 at 06:32:48:

I am looking for a supplier of a VN67AF and 2N5460 transistors. I need a couple for an adjustable LowFER transmitter that appeared in the October 1983 edition of Ham Radio magazine, article by S.J. DeFrancesco. Or, does anyone know of a good, simple (not synthesized) transmitter schematic that is adjustable in frequency without having to change crystals? I am trying to assemble a LowFER station for the first time. One last item: does anyone have any info about the sensitivity of the ICOM 706MkII in the LF range or a modification to make it more sensitive in this range? Thanks and 73's.

Posted by Lyle Koehler lyle mlecmn.net on July 31, 2000 at 10:28:40:

In Reply to: LowFER transistors or Xmitter schematics? 89 posted by Shane Passmore on July 31, 2000 at 06:32:48:

I have misplaced my data sheets on "V-FET" transistors, but it may be possible to substitute the VN66AF or VN88AF for the VN67AF. RadioShack.com lists both of them in their catalog, and they also have the 2N5460. Dan's Small Parts at http://www.fix.net/dans.html shows the VN66AF in his catalog, although his price is higher than RadioShack.com is asking.

Posted by Lyle Koehler lyle mlecmn.net on July 31, 2000 at 10:38:30:

In Reply to: LowFER transistors or Xmitter schematics? 89 posted by Shane Passmore on July 31, 2000 at 06:32:48:

I forgot to respond to the question about the IC-706 Mark II sensitivity on LF. I expect that it's about the same as my original IC-706. In other words, deaf as a post. It will do a great job with a good tuned loop and preamp in front of it; something I'd recommend even for the "hotter" receivers like the IC-751A and TS-870.

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