Past Longwave Messages - February 2001

Addresses and URLs contained herein may gradually become outdated.

New build of Argo
Posted by Alberto di Bene, I2PHD on February 03, 2001 at 16:57:15

Hello all,

I have just uploaded Argo beta 1 build 119.

These are the changes, from the readme file :

Beta 1, build 119 (Feb. 3rd 2001)
- 90s dots mode now enabled
- Automatic save and restore of the settings
- Improved panel to specify capture parameters
- Facility for frequency calibration, both additive and multiplicative
- Buffer allocation streamlined, saving more than 10 MB
- More exact capturing interval (now independent from the vagaries of Windows)
- The ticks spacing has been doubled in each mode, to avoid excessive crowding
- A couple of bugs, that caused random hangs, now exterminated

Please test it, and report any problem you may find, together with suggestions.
TNX

73 Alberto I2PHD

Download site : http://www.weaksignals.com

LowFER Reception
Posted by Robert Bicking, W9RB on February 03, 2001 at 16:59:53

Woke up early this am and heard JDH (CW) @ 1000Z, 2/3/01, 559. Tuned around but didn't hear anything else and when I returned to 184.5 kHz 10 minutes later, didn't hear JDH.

On 1/19/01, also 1000Z, heard BA (549)and BOB (539)for the first time this season.

Also, checked with ARRL but no news on LF ham allocation in US.

Re: New build of Argo
Posted by Steve Olney VK2ZTO on February 04, 2001 at 20:07:04

G'day Alberto,

Have been playing with build 117. Very impressive !!! Congratulations !!! The only crash came when I specified a non-existant file path name for the captures.

There I was thinking with build 117 "wouldn't it be nice if .....", then along comes build 119 and they are all there by the looks. I haven't downloaded 119 but I will soon.

Alberto, would it be possible to rotate the display 90 degrees in the narrowband modes (like the full band view) to maximize the display bandwidth? Also, would it be possible to show the first two peak frequencies instead of the one ? Of course you can easily see where I heading with this - FDK.

Once again - congratulations for making such a fine contribution to our art/science/hobby/fun.

Regards Steve

Re: New build of Argo
Posted by Lyle Koehler on February 04, 2001 at 20:12:45

Subj: New build of Argo Date: 2/4/01 11:28:13 AM Eastern Standard Time From: lyle@mlecmn.net (Lyle Koehler)
To: i2phd@qsl.net, (LowFER reflector), (Longwave Message Board)

I have been using Argo beta 1, build 119 this morning to watch VE3OT's 160m beacon. The slow speed feature is very useful for viewing the signal over a period of several minutes and observing the effects of QSB. Between 1500 and 1620 UTC, Mitch's beacon has been fairly consistently readable, with occasional fades that last a minute or two.
I also like the idea of being able to save settings upon exit, so that Argo is ready to start seeing signals as soon as the program is opened.
Nice job, Alberto!
-- Lyle, K0LR http://www.computerpro.com/~lyle

Re: New build of Argo
Posted by Alberto di Bene on February 04, 2001 at 20:16:34

Lyle,

thanks. I have been suggested to allow to save the settings under various names, so that you can preload, each time you change the operating conditions, the set you want. For the next build....

73 Alberto I2PHD

new medfer 517khz RLD
Posted by Brian Helms on February 04, 2001 at 21:05:11

I finally have gotten around to getting a medfer on the air even though my lowfer is off for the season for improvements due to the fact that it was just thrown together in a few weeks time. My medfer consist of a 11 inch basket weave coil and of course the 3 meter pole w/t tophat. Dex and I did a few tests on it today and found that he could copy it with ~.5mw yes that is -4dbm. He has a great receive setup. It is running qrss day and night unless I am on 160. Not counting on Dex's success but I am going to post it just in case but more of a play toy for me. If someone does hear it then I'll make up some kind of special qsl or something ;).

73's Brian Helms
517khz RLD KD4RLD

Re: New build of Argo
Posted by Alberto di Bene, I2PHD on February 05, 2001 at 04:38:00

> Alberto, would it be possible to rotate the display 90 degrees in the narrowband modes (like the full band view) to maximize the
> display bandwidth? Also, would it be possible to show the first two peak frequencies instead of the one ? Of course you can
> easily see where I heading with this - FDK.

Steve,
thanks for the comments. Have you tried Spectran ? Though in its core perhaps it is a tiny step behind Argo, it lets you choose many things, amongst which the orientation. Spectran is more a general purpose spectral analyzer, while Argo is canned for QRSS/DFCW work. The double peak indication is certainly feasible, I can produce a version for you of Spectran, if you need it.

FDK is quite interesting, and I am giving it a more than occasional thought... in my mind I am considering a modified version of it for a weaksignal communication program. If/when I will write it, you will of course be given due credit. If only I had more spare time...

73 Alberto I2PHD

K0LR and VE3OT beacons on 160m
Posted by Dan Lester on February 05, 2001 at 10:05:58

2-4-01 2235 CST, heard K0LR beacon on 1999.9 KHz, slowCW and IDing at intervals with
10-12 wpm (estimated). Lyle's signal was excellent and although there was no deflection of the receiver 's' meter, the beacon was far above the noise. Rapid QSB noted on K0LR's signal. 2350 CST, returned to the dials briefly and heard VE3OT also on 1999.9 KHz, slow CW with legal ID's of about 10-12 wpm (estimated) at intervals.
VE3OT's signal was very weak, QSB was slow and signal varied from below the noise floor to just above it. QTH here is Seymour, WI. using a Drake R8b, antenna is a "ground"
beverage 1100 feet in length leaving the shack at 270 degrees terminated with a 560 ohm resistor and 8 foot ground rod with a noise reducing transformer and 8 foot ground rod at the feed point.
73 de KE9SE

Re: New build of Argo
Posted by Steve Olney VK2ZTO on February 05, 2001 at 14:34:40

G'day Alberto,

I had a look at Spectran but it's minimum resolution is a bit coarse. Also there is a discrepancy between some of the sample rates giving an error of almost 2 Hz (I can't remember which one now).

Had a rethink on Argo and have decided that I will modify the FDK coding to only include alpha-numerics and an EOT character. This will cut-down span to 4.6Hz which will fit into the Argo display of 30 second dots.

Haven't downloaded build 119 but will do that now. Thanks again. BTW, would be interested to know what modifications to FDK you are thinking of. If you have the time in the future to write an FDK weak-signal program I would like to put forward some of the algorithms that I have experimented with which have an advantage for improving the performance of FDK.

My stumbling block for writing code is that I use the MCI commands exclusively and do file acquisition only. That is, I record a one minute file synchronised to the start of each minute (actually 47.6 seconds long), read the file in and analyse it (using the remaining 12 odd seconds) and produce a single FFT result. I haven't had time (or the strength) to do the level of sophistication that you have achieved.

Regards Steve

Lowfer call sign
Posted by Lewis Denton on February 05, 2001 at 18:29:10

Hi All,
I finally got the bug and am building a lowfer xmiter being a ham i was consitering using my call letters for call sign but noticed that others aren't doing so. is their any reason for it ?
my call is 6 letter should i use only a portion of it to keep it short ?
Lewis wa4lip in South Ms.

Re: Lowfer call sign
Posted by John Andrews, W1TAG on February 05, 2001 at 20:38:41

Lewis,

While you can use anything you want for a call sign, most of the beacon operators prefer to keep things short. These signals are usually heard under marginal conditions, and shorter is better.

Also, if you elect to use slow-speed cw (QRSS) mode, around 0.4 wpm, you might not be able to fit a full ID before a skywave signal fades. I've had receptions where only a few letters showed up, and full copy would not have been possible with an entire ham call sign. The QRSS mode is highly recommended if you want the widest possible "audience."

John, W1TAG

Re: Lowfer call sign
Posted by Lyle Koehler on February 05, 2001 at 22:55:59

While you can technically use anything you want for a call sign on the LowFER band, most of us feel that you can't legally use your ham call sign outside the ham bands. A portion of a ham call sign is often used, though.

SIEMENS VERY LOW FREQUENCY RECEIVER Type 3 U 412 / 3 U 42d
Posted by Dr. James D. Bishop on February 06, 2001 at 07:58:33

I realize that this question is about a long out of production product. However, I hope you can help me with whatever data you may still have regarding the SIEMENS VERY LOW FREQUENCY RECEIVER Type 3 U 412 / 3 U 42d built by SIEMENS) many years ago.

I hope it is not too much trouble.

Dr. James D. Bishop

Re: Lowfer call sign
Posted by R. Bicking, W9RB on February 06, 2001 at 17:57:59

I received the call sign of my dreams thru the vanity program (when I started operating in 1954, the only hams that had 1x2 calls were licensed about 1917). Imagine getting a call with my initials--- I could only remember a few from the old days that did this and they probably knew someone-- like W8JK, the inventor of the 8JK beam and an authority on antennas. But-- as others have said, the noise goes up as the frequency goes down so shorter is better, which is why I use "RB" for my LowFER.73, Rob, W9RB.

CT MedFER beacon operating QRSS
Posted by Clint Turner KA7OEI on February 06, 2001 at 22:42:09

I have started operating the CT MedFER beacon QRSS - at least part-time.

For minutes 0 through 29 past the hour, CT runs QRSS at a rate of 3 seconds/dit For minutes 30 through 59, CT runs its "normal" PSK31 mode.

Upon modifying the beacon to be able to run CW, the frequency got adjusted upwards slightly from what it had been:

It is now operating on a nominal frequency of 1704.957 KHz.

This beacon is now operating at a higher ERP than before: The tophat was "filled in" a bit to increase its capacitance and that allowed me to get rid of the last bit of ferrite in the loading coil - apparently nearly doubling the ERP.

If you get a chance, please look for this beacon.

73,

Clint KA7OEI

LEK transmitting 60 second dots
Posted by Lyle Koehler on February 06, 2001 at 23:34:34

Starting this evening, LEK is sending *very* slow with a dot length of 60 seconds. I think the haywire divide-by-20 circuit I added to the timer chain is working correctly. With an ID cycle time of 32 minutes, it will take a while to make sure. The transmit frequency is still 186.700 kHz, and LEK will be running in this mode at least through the weekend. Perhaps this will help some of you who have been trying so diligently to pick up the signal.
-- Lyle, K0LR

160m beacon schedule
Posted by Lyle Koehler on February 06, 2001 at 23:37:11

Date: 2/6/01 10:28:26 PM Eastern Standard Time To: (LowFER reflector), (Longwave Message Board)

The K0LR 160m QRSS beacon on 1999.9 kHz is on the air this evening but will be shut down until after the weekend. Urgent business (skiing) will result in the absence of the control operator for the next few days.
-- Lyle, K0LR

Re: new medfer 517khz RLD
Posted by Mitch VE3OT on February 07, 2001 at 13:53:18

Hi Brian: did some listening on 517. Unfortunately have an S8 beacon, about 250 miles away. YWA. So he is exactly zero beat with you and from this area it's not possible. Any other frequencies in your magic box closer to Dex?

73 Mitch

Re: new medfer 517khz RLD
Posted by Brian Helms on February 07, 2001 at 16:39:57

Sure, my source is variable in frequency so if I retune my antenna then I can get closer. How close would you like for me to move to him? Would 100cycles be enough? I am pretty flexible and can easily enough modify my coil to change the resonance of the antenna. Just for curiosity, is there a data signal close to 517 in your area?

Thanks Brian Helms KD4RLD

Medfer RLD update
Posted by Brian Helms on February 07, 2001 at 20:24:20

Due to there being a beacon on 517 I have moved my medfer to 510.6 so it will be close enough to NC that they can both be copied in one screen shot. By the way, I am about 6 or 7 miles from NC so I am anxious to compare them to see how much I am lacking. The ground plane for my antenna is 15 quarter wave 160 meter radial all laid out about 20 feet around my antenna(I folded them back on themselves). Not as good of a ground plane as Dex has but anxious to see how it compares.

NC copied again on 510.5
Posted by Mitch VE3OT on February 07, 2001 at 23:32:37

Dex:
Great signal tonight (Wednesday) and clearer ID this time. Posted picture at usual site:
http://technology.fanshawec.on.ca/elec101

73 Mitch

New! TWEB Contents Website
Posted by William Hepburn on February 08, 2001 at 02:36:33

As another LW DX aid, I have added a new webpage to my website. The page lists the information broadcast on the enroute aeronautical beacon broadcasts..or TWEBs. The URL is http://www.iprimus.ca/~hepburnw/dx/twb-wx.htm . Of course - any updates are welcome!! Just E-mail me.

LEK Heard in MA!
Posted by John Andrews, W1TAG on February 08, 2001 at 10:04:47

With Lyle sending in VERY low speed mode (60 second dots), I was able to copy LEK last night. Reception started around 0530Z, and ended at 1200Z, about a half hour after sunrise. Best copy of the entire call sign was in the half hour before local sunrise. There were a couple of complete callsigns overnight, and sometimes I'd just get a really clear letter or two.

Distance is 1110 miles to Holden, MA. Equipment included an Icom R75 receiver and a 14-turn 6' square loop.

I will keep trying each evening while LEK is in this mode, as it's important to know if this was a propagation fluke, or something achievable on a regular basis in this mode. Previous LEK reception at normal QRSS speed has been confined to one night, Jan. 20, where I got some partial call signs. MANY other overnight sessions have been spent looking for this signal, with no results.

John, W1TAG

Re: NC copied again on 510.5
Posted by Dex, W4DEX on February 08, 2001 at 22:58:02

Mitch, This signal from this toy beacon is only a few DB above the noise received at RLD's QTH about 6.5 miles away and not far from line of sight. Once again I am amazed of your ability to pull signals out of the noise.

Dex

WA sending SSQRSS
Posted by Bill Ashlock on February 09, 2001 at 14:36:54

Boston area tests indicate WA is back up to normal power after a one month break in the action. Tonight at 7:00 the QRSS rate will change to 60 sec dots - call this SSQRSS (super-slow QRSS). This rate will continue through at least the next three days during the hours of 7:00pm to 9:00am EST. The day-time transmissions will be normal CW.

Appreciate your listening efforts,

Bill WA Andover, MA

New beacon on 1750 meters
Posted by Donald R Moler on February 09, 2001 at 20:16:32

I just put a beacon on 180.000 KHZ The I.D. is BKR in cw at 5 WPM. The transmitter is located in Girard, Ohio.
( near Youngstown Ohio.) I will be constantly making improvements on the antenna in the next few months there fore my signal will improve with time. I can be found on 3.805 Mhz every morning at 8;30 am ( 80 meters) My call is N8BKR. E- Mail VONJ@cboss.com

WA heard in EN36US
Posted by Bryce Ofstie on February 10, 2001 at 09:29:58

Congratulations to Bill on a strong signal into Duluth, MN. I saw his post yesterday and setup ARGO to capture him last night. Looking this morning I see his signal from 11:30 until 6:00 (local). I'll have to see if the fades correspond to the rotating pattern. The best image occured before
5:00(central) here.

Re: WA heard in EN36US
Posted by Bill Ashlock on February 10, 2001 at 13:45:49

Hi Bryce,

Fantastic clarity on the jpg file! (others, check out lowfer reflector: lowfer@qth.net) I make the distance to be just over 1000 miles to Andover, MA. I had just set up the keyer for the first time to 60sec dots, two hours earlier. What a surprise after being off the air until now! It appears that SSQRSS or QRSSSS or QRSS^2 (or whatever we call it) will have a major impact on Lowfer communications.

Many thanks for your efforts.

Bill WA

LowFER beacon TH heard well in Wisconsin
Posted by Dan Lester on February 10, 2001 at 19:52:49

2-9-01 2120 CST, Beacon TH 189.36 KHz. Good signal, well above the noise, atmospheric noise was low and no competing carriers were within the received passband (500 Hz). TH was ID'ing 15 times per minute, no processing was needed to copy the signal. Using long wire antenna on the ground and r8b. 73 de ke9se

"RB" Beacon on QRSS
Posted by Robert Bicking on February 10, 2001 at 22:24:17

Scrounged a bit to find some large caps and reduced the speed of my beacon keyer to 4 sec dots and 12 sec dashes, as low as I can go until I get to the store to get some more caps or do something more clever. At any rate, "RB" is QRSS at 186.92 kHz. Let me know if you hear it and I'll send a QSL. P. S., ground must have dried out a bit as it has tuned itself back up to max current. Happy listening. 73, Rob, W9RB.

LEK Copied in Alabama!
Posted by Les Rayburn, N1LF on February 11, 2001 at 00:53:20

After months of effort and frustration, I have finally been able to receive LEK in QRSS(S) mode here in Helena, AL. Distance is 972 miles. Not even close to Lyle's
1100+ mile record, but my best DX so far at this location.

I suggested to Lyle that we attempt QRSS(S) mode early this week, but due to work and then thunderstorms, I was unable to make an attempt to hear him. Last night, I ran screen captures overnight without success...this was perhaps the low point of the season for me. Roger in Mississippi seemed to be able to see Lyle's signal with ease, yet my computer screen didn't even show a weak trace...what could be wrong?

Today, I stepped outside and noticed that my 10 foot monster air loop was pointed in the wrong direction!! Lyle's QTH was planted smack in the middle of the 20db null of the loop...
I quickly rotated the loop back into position. Shortly after sundown, Lyle's signal began to come in...now some hours later I have watched it ebb and dip, but remain easy copy for most of the evening.

My next target will be WA who is also running QRSS(S) mode...I hope that more lowfers will try this mode next season...it certainly expands the horizons of possible receptions!

RB seen in EN36US
Posted by Bryce Ofstie on February 11, 2001 at 02:15:45

Rob's beacon can be seen clearly here in Duluth. Congratulations on a nice signal.
I posted it, along with WA, KOLR and VE3OT to my website tonight. I also cleaned up the sounds page so that it doesn't take as long to load. Check out:
http://cp.duluth.mn.us/~ki0le/pages/sounds.htm

73 and good signals,
Bryce KI0LE, BRO

"WA" 185.300 khz Q5 in North Carolina
Posted by Dexter, W4DEX on February 11, 2001 at 08:51:07

I setup on WA's frequency last night about 10 pm EST and let Argo do it's thing over night. The first identifiable signal showed up just after I set up and several good shots were logged over night. The last signal captured occurred at 7 a.m.

Dex

Argo beta 1, build 120
Posted by Alberto di Bene, I2PHD on February 11, 2001 at 15:10:13

Argo beta 1, build 120 has been just uploaded to the weaksignals site :
http://www.weaksignals.com

Changes from build 119 :

Beta 1, build 120 (Feb. 11th, 2001)
- More ticks on the frequency scale (ticks each 0.1 Hz at maximum resolution)
- Named saving/loading of the settings
- CPU overload indicator
- Minor adjustments in the code

Please test it and report any problem or malfunction, TNX.

73 Alberto I2PHD

Re: "WA" 185.300 khz Q5 in North Carolina
Posted by Bill Ashlock on February 11, 2001 at 18:37:52

Dex,

Thank's for the report. This is two scores in the two days that WA has been in the SSQRSS mode!

You were asking about some details on the antenna. This is a pair of 50ft square vertical plane loops that intersect each other at their midpoint. One is mostly 1/2" copper pipe and the other is a tripple run of #12 stranded wire. Both loops rest on a bunch of tall oak tires in the woods behind the house and appear to be holding firm in their position in spite of a number of wind storms.

The transmitter final is mounted at the midpoint and puts out a combination of in-phase and 180deg out of phase signals that results in a rotating propagation pattern. This controlled by the keyer computer in the shack. You should see the strength varing within each group of four WAs in your recording. There's a double wide word space just before the N/S WA. John, WTAG, at 40 miles to the west is reporting a total absense of the N/S segment but the directional characteristics of a skywave path may be different as reported by Paul C about 120 miles from here.

Now that the transmitter appears to be working up to expectations I should be able to dedicate the next few nights to adding some final touches on my article that has the details of putting up a simple #12 loop.

Thanks again for your efforts Dex.

Bill WA Andover, MA

LF Transmitter
Posted by Fabian C. on February 11, 2001 at 20:56:55

I was wondering just how good is the Curry Communications transciever? Is it worth the almost $200 just to have SSB or is it better to just have a CW beacon. I was looking at the LW-MAX Pc controlled exiter, and would like to have 2 way QSOs. Any tips on antennas? I have a 20' pole up right now with an A99 at the top.

Any Tips?

TNX & 73's,
Fabian C.
KD5JDG

Converter CB-VLF ??
Posted by Michi on February 12, 2001 at 08:43:23

Thank you very much for reading my question!

Who can send me a description or manual for changing a CB-radio into a VLF-radio?? Receiving and transmitting!

Thanks a lot!
Michi

European NDBs
Posted by Paul logan on February 12, 2001 at 10:47:40

Hello all, can anyone point me in the direction of an online listing of European Aeronautical NDBs/ or give me any other info on this subject.

Paul Logan, Lisnaskea, Ireland.

LEK copied in Dallas
Posted by Tim Brannon KF5CQ on February 12, 2001 at 12:26:52

Well, I finally got my act together and found LEK on my Argo captures this morning. I saw traces starting about 03:30 CST but no recognizable characters. Found complete calls on 30 minute captures at 05:30 and 06:00 CST. The signal faded about 06:40. Still using the LF converter with a 50 foot wire antenna and a tuner, and no preamp. I intentionally set Argo for 30 second dots thinking they might be too short to distinguish from the background at the 60 sec setting, but this is probably not necessary. Haven't figured out the distance yet. Probably will try for WA tonight.

Tim

Lowfer freq.
Posted by Lewis Denton on February 12, 2001 at 17:17:45

Hi All,
Progress report from South Ms. and question about band edge. I finished the oscillator section of my LOWFER today.
All left is finals and low pass filter and then on to the antenna. my question is how closs are you allowed to band edge. I have a crystel that will put me on 189.755kc, is that two close, I don't want to buy a crystel if i can help.
Thanks,
Lewis wa4lip

New Medfer Beacon, CM97BJ
Posted by Jim Vander Maaten on February 12, 2001 at 18:48:48

I have a new medfer beacon on 1689.6 kHz.
It's AM and the id is 'ESA ESA ESA (4 sec. dash)'.
My location is San Jose, California. There is a broadcast station on 1690 kHz 100 miles away so I don't expect many recption reports yet until I can find a new frequency. Just wanted to let the locals know where it is. The IDer is a 8 pin PIC that cost $6.00 programed. This IDer is the easiest one I have found. You can read about the IDer at members.aol.com/k1el/index.html.
73 Jim

Old Newbie
Posted by Jim Martin on February 12, 2001 at 19:41:25

I used to DX the LF bands years ago and actually learned the Morse Code while living in a house on the beach in Cocoa Beach, Florida. It's great to be back, this time from Dracut, MA and hope to have an LF beacon on the air one of these days. Kind of got tired of ham radio after 20 years and what's been happening to it...maybe this will rekindle the radio fire...I once had. I spent much of this weekend tuning around. My question, I am trying out ARGO and using a Yaesu FT-1000D, holding a microphone next to headphones. Haven't seen any QRSS sigs yet...but can hear plenty of faster stations. What are some of the best audio coupling methods being employed out there? I have set of Timewave audio DSP filters, the DSP-599ZX and the DSP-59Y...probably don't really need them for this as the FT-1000 does a pretty good analog job itself. Any QRSS hints, anecdotes or whatever for an newbie would be appreciated.

Re: Old Newbie
Posted by Robert Bicking on February 12, 2001 at 20:03:34

check some of the postings here. The FT-1000 is a world class radio (I have one). Take a look at the website ofv N1LF: http://www.highnoonfilm.com/xmgr/qrss.htm for info on QRSS.

Re: Lowfer freq.
Posted by Clint Turner KA7OEI on February 12, 2001 at 22:39:10

Having a LowFER beacon on 189.755 is not "too" close - and with it being almost midway between the 3162nd and 3163rd harmonics of the powerline frequency should help should you decide to operate QRSS.

Since you are 245 Hz away from the band edge, you have plenty of room - even if you were to go almost 100 words per minute.

The only thing that might overlap the band edges would be keying transients due to the risetime of the keying - if the risetime were faster than 5 milliseconds or so, then the upper keying "sideband" (i.e. the key click") might fall outside the band, but that may be splitting hairs:-)

Clint KA7OEI

WA in Ontario - 98 to go !
Posted by Mitch VE3OT on February 12, 2001 at 22:43:55

Hi Bill:
Just a repeat here about your great signal, received this evening at 10:20 PM EST (0320Z) on 185.300.
Audible at times, and increasing in strength now.
Picture at http://technology.fanshawec.on.ca/elec101.
Congratulations - Lopp's sure working.
73 Mitch

For Lopp read loop !
Posted by Mitch on February 12, 2001 at 22:45:25

Got so excited I couldn't spell LOOP.

73 Mtich

Re: Old Newbie
Posted by Tim Brannon on February 12, 2001 at 22:45:53

Most newer HF rigs like this have a high impedance audio source on the back panel somewhere. My ICOM 738 has this on one pin of a DIN accessory plug, so I made up a shielded audio cable with the appropriate plugs. This just runs direct to the "line in" jack on my SoundBlaster card, and I use the Windows Volume Control applet to adjust the input level. This lets me adjust the rig's volume control without any effect on the feed to the computer. The FT-1000 manual probably has a section on connecting a packet TNC or multimode data controller with applicable hookup info.

Re: For Lopp read loop !
Posted by Bill Ashlock on February 13, 2001 at 01:54:50

Hi Mitch,

Loop or Lopp, Mitch or Mtich - who cares. I'm pretty excited too, what with a .750 batting average in the last 4 days (and the night ain't over)! This antenna appears to have a nice skywave angle. Just looked at your ARGO record and it looks good.

Three cheers for this very Sloooooooow QRSS!

Thanks for your efforts Mitch.

Bill WA
185.30

PS to Les: It looks like your suggestion has paid off

Re: Old Newbie
Posted by Bill Ashlock on February 13, 2001 at 09:53:04

Hi Jim,

Glad to see a local LF enthusiest on the scene. I make out the distance between us to be only about 10 miles. According to the math WA should be pounding in at your base at about 30 uv/m so keep an eye on the gain control! I'm currently running normal CW rates during the day but switch over to very slow QRSS at ~8:00pm (easy to miss the signal if a 3 min word space happens to be going on). Hope you eventually set up a beacon transmitter as it would be great to do some two-way CW. Be sure and let me know if there is any way I can help you out and drop by if you would like to see a dual Xmitting loop setup.

Bill WA Andover, MA
185.30

LEK reception reports
Posted by Lyle Koehler on February 13, 2001 at 16:40:25

Subj: LEK reception reports Date: 2/11/01 9:44:20 PM EST To: ad5t@arrl.net (Roger V. Thompson), w1tag@charter.net (John Andrews), les@highnoonfilm.com (Les Rayburn), lowfer@qth.net (LowFER reflector), lwcanews@aol.com (Longwave Message Board)

I returned from my ski trip to find a whole stack of e-mail messages including reception reports from three new states. Maybe I should go away more often! Even with the help of *very* slow CW, those are still amazing feats of reception. Thanks and congratulations to all.

Map trivia: My location is EN36EK, and the actual lat-long coordinates are 46.45 N, 96.62W. Since my old address was a rural route box number and my new "street" address is too recent to be in any map databases, my location is given differently depending upon where you look. The callsign database puts me in the the town of Aitkin, MN (I'm about 8 miles southeast of there), and the on-line map services usually stick me in the middle or the east shore of Elm Island Lake. That happens to be correct within a mile or so, because I actually live at the southeastern tip of the lake. However, it turns out that *any* rural address in zip code 56431 shows up at that same location. Apparently I live fairly close to the geographic center of the zip code area. I have corrected the QRZ listing for my coordinates, but need to do the same thing on the Buckmaster web site.

Once again, thanks to everyone for trying so hard to hear my beacon. QSL cards will be in the mail shortly.
-- Lyle, K0LR

WA back on 1000 track
Posted by Bill Ashlock on February 13, 2001 at 19:13:03

WA is back to a batting average of 1.000 as the result of two skywave reports last night. Lyle's late report brings the total to 4 in the four days transmitting in super slow QRSS.

Glad to see you back on line Lyle - and no broken bones!

Bill WA Andover, MA
185.30

Re: Old Newbie
Posted by Jim Martin on February 13, 2001 at 22:47:19

Hi Bill,

Thanks for the invite. Plan on me taking you up on that.

I was listening to your beacon earlier this evening before it went to QRSS. My antenna is not the greatest right now. Just about 175' of AWG 12 wire at ten feet running down one side of the property and across the back...my lot is 225' x 75' and as soon as the snow goes away I'll go out a put some more wire up. My lot is right on the Lowell line and there are woods beyond that...so can fudge it a bit farther than my property line.

I am getting the materials together for a loop right now. The first dit of WA just went by, 579 here in Dracut. Sig ought to pick up with a better antenna here...

Geeze Bill, this is the slowest code I've ever copied by ear. hehehe. Even slower than the flashlight, look it up code across the reservoir at Boy Scout camp (Camp Winton) in California during the summer of 1968. It is painful...hehehhee. I'll have to fire up ARGO here in a short.

Wonder if the town will feel better about me putting up my tower if they felt it would put them on the map..har har...

Thanks again.

GLS frequency please
Posted by Rick on February 14, 2001 at 07:18:02

Several of the Australasian LF group are using the Argo program to dig weak NDB's out of the noise. The latest version has been used here in Port Moresby in an attempt to ID GLS from TX. Problem is, we have several carriers on the plot and no idea which is which.
Can anyone there give an accurate frequency for the GLS carrier - needs to be within .1Hz Using HF1000 MFJ784 and Argo 119 soon to be 120.
Thanks all. Rick and lofexp@egroups.com

Re: Converter CB-VLF ??
Posted by Mike on February 14, 2001 at 10:28:02

A CB set with a transverter (transmit and receive converter)would not be stable on LF/VLF -- the CB has a frequency tolerance of only .005%, and can wander hundreds of hz. A transverter might also generate spurious signals on frequencies near the CB channels.

It would be better to buy the parts and build your LF/VLF station. There are designs available; visit the links from this site. And keep asking questions! Good luck, Michi.

Mike, AJ1J
"CA" Carmel, NY

Re: European NDBs
Posted by Mike on February 14, 2001 at 10:36:36

There is a list of navigational stations worldwide, LF and VHF, at -- www.fallingrain.com/air/airports.cgi

Mike, AJ1J

WA in daylight QRSS
Posted by Mitch VE3OT on February 14, 2001 at 11:19:31

Nice signal from Bill at 11AM EST (1600Z) here ion a foggy morning in London, Ontario. Normal electric utility noise (S5 this morning) but WA clear on ARGO (10 sec dots).
73 Mitch VE3OT

Re: WA in daylight QRSS
Posted by Bill Ashlock on February 14, 2001 at 12:49:35

Mitch,

What is going on here? Why is my bench light dimming at 60 sec and 180 sec intervals? (ha ha)

Thought that skywave propagation was pretty much limited to the dark hours. Possibly this is related to the seasonal change coming up? Or with this QRSS stuff do we now have a year-round season for Lowfers?

Comments anyone please?

Bill WA Andover, MA
185.3

LEK copied in Maryland!
Posted by Larry Putman on February 14, 2001 at 14:25:00

Early this morning at 0120 EST I copied LEK using my Ten Tec RX340 and 80' inverted L antenna and Argo 117!

This is the most distant lowfer that I have copied at a distance of 1010 miles! Thanks to Lyle for the great signal!

Larry WB3ANQ

Re: WA in daylight QRSS
Posted by Mitch VE3OT on February 14, 2001 at 15:37:48

Followup - signal solid until 12 noon - faded out until 1430 EST and back again solid at 1530 this afternoon, so only a two hour (approx) period during which no copy here in foggy London town.
Mitch

60khz Antenna
Posted by MItch on February 14, 2001 at 16:25:44

I have an HP 117A 60khz freq. comparator. I'm missing the preamp and antenna. I was wondering if there was an antenna I could substitute for the HP pre-amp/antenna. I have the HP schematic and information (the receiver has a +35v at the antenna conncection).

I have a circuit for a preamp/antenna, but I'd prefer to buy rather than build.

Any information would be greatly apprecited. Thanks.

Re: WA in daylight QRSS
Posted by Lyle Koehler on February 14, 2001 at 18:47:56

A rather ragged "WA" appeared on the Argo screen between 0930 and 1000 CST today. About half an hour after that, my noise level came up and was pretty bad for the rest of the day. At this time of year, there obviously is still *some* skywave propagation even during daylight hours. DIW is typically readable all day, but they're running a bit more power!

Last night while walking the dog at about 2230 CST I saw a brief burst (maybe a minute or two) of fairly bright aurora. It was too cold to stay outside and see if it returned...

Re: GLS frequency please
Posted by Tim Brannon on February 14, 2001 at 23:53:47

Hi Rick,
I live about 300 miles north of GLS in Galveston and have a good copy 24 hrs a day. With a receiver that tunes in 1 Hz increments, I used the Argo software to achieve the 0.1 Hz resolution. I set the receiver dial to 60.000 kHz for WWVB here in the US, and then using Argo in 3- second-dot mode I adjusted the calibration variable until I had a line on 800 Hz (center of my CW passband). I then repeated this in 30 second dot mode to acheive a resolution of 0.021 Hz. (The Argo sensitivity had to be turned way down to get a clean line). Then I set the receiver display to 206.000 kHz, and Argo showed a continuous carrier at 801.9 Hz. Tuning the receiver to 205.998 Hz put the carrier line just below 800.0 Hz, so I interpolate the GLS frequency to be 205,998.1 Hz or 205.9981 kHz.
I've been trying a few tricks to improve my frequency stability, so I'd also appreciate some other listener's measurments. I'm setting up now for an overnight run to copy WA near Boston in QRSSss, but I'll repeat this a few times tomorrow and see what I come up with.
Tim Brannon

Re: Old Newbie
Posted by Bill Ashlock on February 15, 2001 at 04:53:33

Hi Jim,

Sorry to be a day late on this comment to your post. I'm still on cloud nine on this late success with the slooooow CW and he reports are coming in more frequently than I can keep up with. Did you see the earlier post where I indicated that WA had been off the air for a month? I've received an average of one report per day since turning on the switch last Friday. Two receptions during the day today. Lyle's is from a distance of 1150 miles!

How's the noise level at your home base? This is a crtical factor in Lowfer reception - at least it used to be before QRSS took off. My best antenna is a 3ft E-probe (simple 2-stage amp driving coax lead-in) that is elevated 40 ft off to the side of of the lot and is almost in contact with a tall tree. The signal strength and S/N improves considerably with elevation. The S/N especially improves with distance away from the noisy house wiring. A coupling transformer is esential at the shack end of the lead-in to isolate the power line noise riding on the receiver's chassis from driving the ground side of the antenna.

Happy Lowfering - hope to meet with you soon!

Bill

GLS and WWVB
Posted by Rick on February 15, 2001 at 05:29:22

Tim,
Thanks for the help which I have passed on the low frequency group here in Australasian region at lofexp@egroups.com I hope to copy WWVB tonite with some luck.

Also have copy on CFH on 137KHz, quite good S/N I would say, but not audible !!

Regards

GDX NDB Address Needed
Posted by RFU on February 15, 2001 at 08:13:25

Hi all,

Does anyone know the mailing address I need to verify the NDB GDX on 227 khz? Has anyone else logged this NDB?

Thanks.

New detection system for 1750 meters
Posted by Donald R Moler on February 16, 2001 at 00:40:20

I am looking for someone to help with a below the noise detection system. I have just built a synchronous detection system using WWVB on 60 KHZ as the reference signal. I have built a one watt transmitter on 180 KHZ that uses a high Q five foot square loop tuned to 60 KHZ which is amplified and then multiplied by three then amplified again to give me a beacon output of one watt on 180 KHZ. Now my beacon on 180 KHZ is traceable to WWVB. Now anyone in the receiving range of WWVB can build a receiver loop for 60 khz and receive my signal using a synchronous detection system with WWVB as the reference signal into a double balanced mixer. Such a receiver will have a bandwidth of much less then one cycle and is easy to build. Such a system would have far greater sensitivity to weak signals that are below the noise then any system in use on 1750 meters now.

on air
Posted by Donald R. Moler on February 16, 2001 at 00:49:10

My beacon that is referenced to WWVB is now on the air every weekend and will be on 24 hours a day every day of the week as soon as I finish improving my antenna. I am out to get the record DX signal on 1750.

Re: New detection system for 1750 meters
Posted by Les Rayburn, N1LF on February 16, 2001 at 10:09:30

Donald,

Glad to hear about your efforts. We still need more information to post to the web pages and the Lowfer list. What mode are you transmitting on? What is your ID? Hours of operation and grid square.

Also, be advised that even frequencies such as 180.00khz usually present problems with carriers and other noise sources which often fall at even frequencies.

And I'm sure we'd all like to see and hear more about your synchronous detection system using WWVB on 60 KHZ as the reference signal. Those of us interested in pushing the edge of weak signal detection all agree that synchronus detection represents the best chance of improving on QRSS(S), however, such systems suffer from being more complex to build and operate. A simplier solution than those that have been proposed would be just the ticket.

At present the lowfer distance record is a path from Hawaii to California that will prove difficult to beat.
However, the "continental" record is not within reach...
the biggest limiting factor at the moment is that we are currently lacking "serious" listeners on the West Coast. Most of the weak signal work is being done back East...but perhaps someone out there will take up the torch next season.

Please let us hear more about your beacon and your experiments. Welcome to 1750 Meters!

For the latest news on operations, current experiments,
QRSS, and other 1750 Meter news visit the Noise Floor web site:

http://www.highnoonfilm.com/xmgr

Re: New detection system for 1750 meters
Posted by Lyle Koehler on February 16, 2001 at 12:30:31

Don's proposed scheme is something I have wanted to try since I first got interested in LF back in the 70's; in fact my original LowFER beacon was slaved to a WWVB reference. However I never got around to building a receiver for it, and my best DX in straight CW mode was about 15 miles with the kludge antenna I was using. There are two potential problems with the technique. First, WWVB puts out a third harmonic signal on 180 kHz that is audible at my location, so it would swamp out any *really* weak signals on that frequency. That isn't a fundamental problem; it just means that the transmitting and receiving systems have to be a little more complicated, using frequency synthesizers locked to a WWVB reference to get to a clear spot in the spectrum.

A more fundamental limitation is the phase stability in the propagation path itself. Bill de Carle has run some tests indicating very little phase instability in transatlantic propagation of BBC Home Service signals on 198 kHz. However, many of the QRSSS LowFER reports are showing significant amplitude variations over time intervals of only 10 or 15 minutes, and my gut feeling is that there would be considerable phase variation as well. This may set a limit on weak-signal detection using fully coherent techniques with long-term integration. But we'll never really know unless we try.

Re: New detection system for 1750 meters
Posted by John Davis on February 16, 2001 at 14:21:51

Lyle phrases both major potential drawbacks very well.

That's not to say there's no benefit in playing with such an idea, but it's good to start with reasonable expectations. Therefore, let me also bring up a few more points worth considering as well.

Synchronous detection does not inherently mean very narrow bandwidths. That is a function of receiver design, which in turn must take into account the proposed modulation method, which you have not yet defined.

Also, for synchronous detection, it is not enough to inject a received signal into one port of double-balanced modulator with the reference signal at the other port. That only works if (a) you are attempting to detect the presence of a carrier, or you are receiving an amplitude modulated or on-off keyed signal, that just happens to be in phase with the reference, in which case the output of the mixer will be a DC level or baseband audio corresponding to the envelope of the receiver input; or, (b) you are attempting to demodulate phase shifts in the incoming carrier, and the input and reference happen to be 90 degrees apart in phase.

With the technique as you describe it, you can never be sure of the phase of the incoming signal relative to the reference, even if both are perfectly locked to WWVB. The path lengths will affect phase, and the propagation effects mentioned earlier will keep it varying somewhat. Hence, while you can stabilize both the transmitter and receiver FREQUENCY from a single source, you will need a way at the receiver of adjusting to find the In-phase or Quadrature condition, depending on your modulation method. You can do it manually, or with a Costas loop, or with a plain PLL. In any case, you basically need both an I and a Q demodulator (just the same as you were thinking, but with one having the reference shifted by 90 degrees) and involving both in the detection process.

(Also, please be sure to send the information Les and I have requested to the part15@lwca.org address, so we can get it listed on the Web site and in the publication. Thanks!)

73,
John

WA's tally for the week
Posted by Bill Ashlock on February 16, 2001 at 18:38:10

WA is ending the 7-day marathon for super slow QRSS (60 sec dot times). The average number of skywave reception reports per day was 1.111. The following is the tally:

Friday: Bryce O. 1000+ miles Saturday: Dex M. 600+ miles Sunday: No reports Monday: Mitch P. 533 miles and Lyle K. 1150 miles Tues: Mitch P. 533 miles and Roger M. 1000+ miles Wed: Mitch P. 533 miles and Lyle K. 1150 miles (both were daytime reception!)
Thurs: No reports

Must be something to this mode of operation!

Tonight there will a pause in the action while I will make some changes to the directional pattern of the loop antennas via the software. The goal is to alternate the signal from the regular 4 direction pattern to a simple 2 direction N/S and E/W pattern to determine the effect on readability. The mode will continue to be QRSSS with 60 sec dots. Should be up and running by 11:00 PM EST.

Thanks to all the QRSS listeners out there. It's been quite a week!

Bill WA Andover MA
185.30

Beacon MV on air
Posted by Tim Pauly on February 16, 2001 at 22:17:55

Beacon MV is back on the air.

Frequency: 187.600 kHz.
Mode: CW; ID 3x then 5 second carrier Location: Salisbury, NY Hours of operation: 9pm to 6:15am m-f, sporadic weekends.

second station
Posted by Donald R. Moler on February 17, 2001 at 00:15:01

I am building a second station to transmitt and receive on 1750 meters. This station will be located on a farm near Saxonburg Pa. and will use synchronous detection also. The two stations will be about 80 miles apart and give me a way to test the complete system. It looks like the variation in arrival time of the 60 Khz WWVB due to the path length changes will be the same for both the transmitting station and the receiveing station and should come close to canceling out. Also, for the short time that I will be intergrating the signal, the path length won't change much. ( I hope ) I do have a phase shifter that came out of a NDT tester and I can rotate the phase 360 degrees. Back in the 60's I worked at Yale U. and took care of the time base's and used the HP VLF receiver. If I remember correctly the only time there ever was a large shift in time delay was at sunrise and sunset. We also had a atomic clock to check the VLF receiver. Don Moler Girard Ohio

WA received in Maryland!
Posted by Larry Putman on February 17, 2001 at 08:37:32

Bill,

Your new pattern works well down here!!
I did an overnight Argo capture and started seeing your signal just after midnight and it peaked around
0330 EST.

First time I have seen your signal this season after countless hours of watching! :-)

Larry Putman WB3ANQ

WA's tally for the week
Posted by Bill Ashlock on February 17, 2001 at 09:13:27

WA is ending the 7-day marathon for super slow QRSS (60 sec dot times). The average number of skywave reception reports per day was 1.111. The following is the tally:

Must be something to this mode of operation!

Thanks to all the QRSS listeners out there. It's been quite a week!

Bill WA Andover MA
185.30

Bill Cantrell's analysis article in IEEE Trans. on MTT
Posted by Mark Kahrs on February 17, 2001 at 11:36:47

Hmmm, some guy named William H. Cantrell published an article named "Tuning Analysis for the High-Q Class E Power Amplifier"
in IEEE Transactions on Microwave Theory and Techniques,
December 2000, pp. 2397-2402. If worse comes to worse,
you can find this at your neighborhood university library.

In it, he analyzes class E operation and then describes a 1 W transmitter with an output frequency of 189.7 kHz...

LW RTTY STATIONS
Posted by John Fog W2IMX on February 17, 2001 at 12:44:06

I'am picking up lots of RTTY sounding stations in my area,
northern New Jersey, all over the long wave band. I have an old PK-232 TNC but unable to print any text. It's all garbal. Can anyone fill me in on what these stations are all about and how to print them.

TNX John W2IMX

Re: LW RTTY STATIONS
Posted by John Davis on February 17, 2001 at 13:39:34

There ARE a lot of RTTY stations on LF, but not literally "all over" the longwave band. I wonder if you could describe the sound and on what frequencies it appears? There may be other explanations.

John

Re: WA received in Maryland!
Posted by Larry Putman on February 17, 2001 at 14:14:19

I have put up a very crude website to display some screen captures of my recent receptions at

http://www.dataserv.net/~larryp

LF Beacon "NC" off air
Posted by Dexter, W4DEX on February 17, 2001 at 15:02:09

The LF beacon's coil house was blown off the building roof when a guy line broke during high winds last night. The 40 pound coil with varoimeter was badly damaged. A fast moving front produced 60+ MPH winds here on the hill top. 177.777 khz will be off until further notice.

The MF beacon survived due to insufficient wind loading and continues to ionize the atmosphere. Skywave QSL #2 is still available. 510.500 KHz QRSS 3 dot sec

Dexter

74HC4059's
Posted by Chris Lantaff on February 17, 2001 at 20:04:42

Also anyone looking for the hard to find CD4059, I just ordered a few @ $2.95 from Electronix Express www.elexp.com $20 min order plus shipping

Chris Lantaff, KE9YK Evansville, IN YK 185.97 KHz

Jitter
Posted by Donald R Moler on February 18, 2001 at 14:48:43

When I triple the 60 khz WWVB signal to 180 khz I end up with short term phase jitter on 180 khz from the amplitude modulation on the 60 khz signal. I just found this out when I beat my beacon against a crystal oscillator. This may not be a problem with synchronous detection with long term intergration, just the same I am going to generate my signal from a crystal oscillator and lock the oscillator to WWVB in order to have short term stabilty also. Don Moler

LEK WOLFing on 186.700
Posted by Lyle Koehler on February 18, 2001 at 16:47:58

To: (LowFER reflector), (Les Rayburn), (Stewart Nelson), (Longwave Message Board)

Starting this evening, LEK is transmitting BPSK in Stewart Nelson's WOLF format. Details of the format and downloadable files are available at http://www.scgroup.com/ham/wolf.html

WOLF presently works only in "off-line" mode. To decode LEK's signal, you need to record a monaural WAVE file of the signal at 8000 samples per second, save it as wolfr.wav in the same directory as wolf.exe, then invoke the "wolf" command and wait. I tried recording a 5-minute sample of my own signal and then mixed it with noise, in the same manner used for comparing other weak-signal modes in my web page article. WOLF was able to extract the "LEK LEK LEK" identifier after processing 96 seconds of a file with the signal attenuated by 33 dB, and after 288 seconds at -37 dB. The 5-minute sample apparently wasn't long enough for a signal attenuated by 40 dB. Your own mileage may vary, depending on the sampling rate accuracy of your sound card and the frequency accuracy of your receiver.

LEK should be well within 0.1 Hz of 186.700 kHz, and I have attempted to correct the transmitted signal so that the bit timing is as close to 100 milliseconds as possible.

WOLF may not work as well as QRSS(S) with 90-second dots, but it should do a lot better than QRSS at 3-second dot lengths. Again, frequency and bit timing accuracy will have a very significant effect on the results.

Good listening!

Lyle, K0LR http://www.computerpro.com/~lyle

Re: New detection system for 1750 meters
Posted by Don Moler on February 18, 2001 at 16:57:02

I will try to answer some of the questions that are being asked.

First I made my 60 khz receiving loop so as to have a high Q and try to eliminate having a high amplification preamplifier. The loop was made from two boards 5 inches by 5 foot 10 inches and half inch thick. I crossed the boards to make an "X" and wound # 14 copper wire around the X leaving spacing between the wires in order to increase the Q. I then added a five inch board to the end of each leg so I could wind another set of windings above the first. I then added silver mica capacitors to resonate the loop at 60 khz along with a 360 uufd variable air capacitor to adjust for any change in the inductance.

I mounted the preamp right in the center of the loop in a small chassis. the preamp consist of two mpf 102 J fets. as a differential pair. I had these drive a transformer that I wound on a high Q core that encased the winding to element any external field and prevent feedback to the loop and cause oscillations. This transformer had two windings, the first had a center tap for supplying the D.C. to the FET'S, The other winding to drive the coax that goes to another amp located in my house. I built this very heavy loop in my basement and when I took it outside the Q of the loop went up and it had a tendency to oscillate so I dropped the supply voltage a little and that cured the problem.

In the house I amplify the 60 khz and clip it by driving it into saturation. I did this because I was afraid the amplitude modulation that is being used on the 60 khz WWVB signal would shift the phase of the output of my amplifier. (In order to send time information in binary, WWVB reduces the carrier by ten DB. This means going from 50,000 watts to 5,000 watts.) I then triple the 60 khz to 180 khz then amplify it again to clean it up.

The path time variable from WWVB to my house in Ohio is guaranteed to be better than 100 microseconds and in the daytime under normal conditions it should not vary more than a few microseconds. This is good enough to do long term signal averaging. We all know that signal to noise ratio varies as the square root of the bandwidth and this holds true even if the bandwidth is less than a cycle per second so by integrating the output of the double balanced mixer we can have a bandwidth as short as the phase change of the two signals will allow. I don't know what that is but I am going to find out soon. I have my system up and operating but I still have a lot of bugs to get rid of and I will keep every one posted on my advances.

The call I am using is BKR it comes from my ham license N8BKR. I am located in Girard Ohio, near Youngstown Ohio.

The hours of operation are random for now. When I am transmitting I send 5 wpm in cw. In the future I will try modulating the signal with a division of 60 khz. I am going to try to set a DX record on 1750 meters and there is lots to do before I can get there.
I would appreciate all the help and advice anyone can give me ... I am on 80 meters every morning at 3.805 mhz. Thanks

Don Moler N8BKR

Re: LEK WOLFing on 186.700
Posted by John Andrews, W1TAG on February 18, 2001 at 17:36:40

After downloading a copy of WOLF.EXE, I set CoolEdit to record 75 minutes from 5:15 AM to 6:30 AM EST today (2/18), with the receiver set for LEK on 186.700.

After breaking the resulting file into chunks, I find three lines of solid copy between 6:10 AM and 6:20 AM EST, about a half hour before local sunrise. Lyle was sending "LEK LEK LEK", and that appears on each of the three lines.

My earlier experience in receiving LEK was nil with 0.4 wpm QRSS cw, and pretty good just before sunrise with 60 second dot QRSS(S) cw. To transfer those three lines in a 10 minute period represents a substantial improvement in information content.

The distance involved is 1110 miles. Receiver is an ICOM R75, and the antenna is a 14-turn square loop, 6 feet on a side. The loop is series tuned, with a preamp inside the house.

John Andrews, W1TAG

Re: LEK WOLFing on 186.700
Posted by Lyle Koehler on February 18, 2001 at 18:54:00

I changed the identifier string a little bit today, to make better use of the 15-character limit presently imposed by WOLF.

Also, this afternoon I recorded an 11.2 minute wave file of my signal and pasted two copies of it end-to-end to make a 22.4 minute sample. I attenuated the signal by 40 dB (using Cool Edit) before mixing with my "standard" noise recording, and the results are shown below. It took the full 11.2 minutes (7 repetitions of the message) to recover the message the first time. Then there was a missed line, which might have been because of a glitch in phase where the files were pasted together, followed by solid copy. 11.2 minutes is a big improvement over QRSS with 60-second dots. Using the same test on a QRSS-60 file, the single letter "L" takes exactly 12 minutes to transmit, and is very rough copy on the Argo screen at -40 dB. That's at least a 15-fold improvement in "throughput", which can be very important if the band opening only lasts for 10 minutes! Besides that, there is little question that the message is there when it finally comes through, which can't always be said for copying Morse by ear or by eye.

D:\Ham\LF\Wolf>wolf WOLF version 0.21 t: 24 f: 0.632 a:-1.4 dp: 98.2 ci: 3 cj: 27 M*V10EJC4I7E9NH ?
t: 48 f: 0.193 a: 0.5 dp: 95.7 ci:15 cj: 33 41F/FQZ28ZEIN6M ?
t: 96 f:-0.608 a:-1.0 dp: 92.2 ci: 3 cj:150 2FZYXLDAZNDOR U ?
t: 192 f: 0.303 pm: 75 jm:535 .F9998VZXANIJ9D ?
t: 288 f:-0.586 pm: 88 jm: 34 QJT99 ZE7HCKQED ?
t: 384 f:-0.010 pm: 105 jm:185 MT79W67FIG.3BQ9 -
t: 480 f:-0.010 pm: 223 jm:185 MT68PV 03 9FBQ9 -
t: 576 f:-0.010 pm: 230 jm:185 Z18YCVJN7U.MJUR ?
t: 672 f:-0.010 pm: 263 jm:185 DE LEK AITKIN* -
t: 768 f:-0.010 pm: 288 jm:185 DE LEK AITKIN* -
t: 864 f:-0.010 pm: 311 jm:185 IYI/GFLO1GOYR24 ?
t: 960 f:-0.010 pm: 335 jm:185 DE LEK AITKIN* ?
t:1056 f:-0.010 pm: 392 jm:185 DE LEK AITKIN* -
t:1152 f:-0.010 pm: 514 jm:185 DE LEK AITKIN* ?
t:1248 f:-0.010 pm: 521 jm:185 DE LEK AITKIN* ?
t:1344 f:-0.010 pm: 554 jm:185 DE LEK AITKIN* -

All of this proves only that I can receive my own signal under simulated "real world" conditions. Fortunately we already have John's reception report to show that WOLF really does work!

WA sending 2-speed QRSS
Posted by Bill Ashlock on February 18, 2001 at 19:25:27

Beginning tonight WA will alternately send one 20 sec dot- time WA and one 60 sec dot-time WA in each loop direction. The loop pattern will be the simpler 2-direction N/S - E/W version so that the effect of the QRSS speed will be easier to analyze. Hopefully the 'S/N gain' with the slower speed can be seen on a single screen capture.

Signal reports will be greatly appreciated.

Bill WA Andover MA
185.30

Re: New detection system for 1750 meters
Posted by Ron Kovach, Langhorne Pa on February 18, 2001 at 20:20:42

I had been using a similar system for a year or so here at my location, but has been put together with high end stuff bought at flea markets. Currently using an Austron Loran C receiver and phase locking a crystal oscillator to the Loran C station. This oscillator drives a frequency synthesizer and a lock-in amplifier, with the lock in tuned to 60 khz (or any other frequency up to 100 khz). The system was used to detect Sprites, caused by thunderstorm discharges, that ocurred along the propagation path.

Re: Jitter
Posted by Ron Kovach, Langhorne, Pa on February 18, 2001 at 21:33:46

Hello Donald:

I just took a look at 180,000.0 Hz and I see what looks very much like WWVB time code coming through. Also coming through at 120,000.0 Hz, but much weaker. The third harmonic of 60 kHz is quite strong. I am in a very noisy location here, but goes quiet around midnite. Will check it out again at that time. I see the usual suspects from Europe (DCF77 Mainflingen, DCF139 Magdeburg etc.) so propagation is pretty good now.
Anyway, the important thing is that the harmonic may cause you problems on the receiving end.

Displacement Current Whistler Receiver
Posted by Scott Fusare on February 19, 2001 at 08:37:14

Thanks to Dick, PA0SE, for putting up the link to Dr. Nordholt's work. I have been toying with this idea for a while and feel that it has some great advantages over the high impedance approach.
I thought I had come up with something new and exciting when I came across Dr. Nordholt's U.S. patent on the idea (ain't it always the way). In theory, the circuit is immune to shunting capacitance (virtual ground, can't charge). Also, as the source is capacitive, using capacitive feedback gives a flat frequency response (within the limits of the device). My foray into this approach, using op amps in the transimpedance configuration, has been successful on the bench - but less so in the field. Happy to have the design using discreet components to try.
Would love to hear from anyone who has tried this idea. For those that would try the op amp approach an ultra low (fA) bias current device is needed. The circuit is an integrator at heart and will happily integrate the bias current (into a tiny cap) and quickly hit one of the rails. U.S. Patent# 4414690 at http://www.uspto.gov/patft/index.html , covers the theory for those that are interested, but don't have access to the IEEE journals.

Re: New detection system for 1750 meters
Posted by Larry Putman on February 19, 2001 at 09:21:25

Don,
There are two other beacons listed as operating on 180Khz.
One is in the east and the other in the west. If either or both of these stations are active how would this effect your new detection method?

Larry WB3ANQ

Re: Displacement Current Whistler Receiver
Posted by Donald R. Moler on February 19, 2001 at 10:42:53

Charged coupled amps have are in wide use in nuclear research, and they have been used elswhere for many years. They are generaly used after detectors that have high capacitance and a fast response is needed. They make it look like the generating device does not have any capacity. I have used them at Yale U. and Bell labs and found that they really do work where nothing else does. Don Moler

loops
Posted by Donald R. Moler on February 19, 2001 at 11:21:43

I am not up to date on receiving loops, but I found out that if a receiving loop is hooked up to a preamp with a differential pair of FET's at the input, it helps to find the center of the loop and ground it near the preamp input This seems to eliminate a lot of garbage. This may have been done before, but I am not aware of it. Don Moler Girard, Ohio

WWV, a silent key?
Posted by Tim Pauly on February 19, 2001 at 13:58:07

This came across the remailer on broadcast.net. I thought it would be of interest to the LF community. Please excuse the cut-and-paste forwarding.

> Dave, KJ9I, informs that NIST will be conducting a survey to determine
> if/how the 5, 10, 15 MHz WWV broadcasts are being used in May of this
> year. Dave questions if this study may be tied to a feasibility study
> to determine if the service will be continued. So if you use WWV,
> please participate!! In order to get a survey send an e-mail request to
> NIST.radio@Boulder.net.gov and include your mailing address.
>
>
> 73 from Bill Smith, W5USM
> "Shortwave Since 1950"
>
>
>
>
> Sponsored by the Collins Collectors Association http://www.collinsradio.org
> Nets: Tues: 3.805 Mc-2000 Central / Thur: 3.875 Mc-2000 Central
> Fri: 3.895 Mc-2000 Pacific / Sun: 14.263 Mc-2000 UTC

Re: loops
Posted by John Andrews, W1TAG on February 19, 2001 at 16:23:24

Don,

The subject is not new, but certainly is not widely discussed. For a good preamp, check out Lyle Kohler's site:

http://www.computerpro.com/~lyle/bal-pre/bal-pre.htm

Another approach is to series tune the loop into a coupling transformer, avoiding any ground connection on the loop side of the transformer. The balance to ground is then only limited by the physical layout of the loop and the symmetry of the transformer.

John Andrews

Re: LEK WOLFing on 186.700
Posted by Mick Reed on February 19, 2001 at 16:30:08

Sure! If you're not a purist who insists on copying by ear, why not use WOLF? I can imagine people complaining about how WOLF is like 'cheating' even more than QRSS viewers are. No way.

Re: Bill Cantrell's analysis article in IEEE Trans. on MTT
Posted by Mick Reed on February 19, 2001 at 16:36:56

Yes, I got a copy of this article. It is essentially the same as the HTML version (see www.k3pgp.org), but shows more of the equations used. Now that I have read both versions, the theory is much clearer to me now. BTW I got my Class-E working and I am trying to figure out if I can calculate my antenna loss resistance by varying and measuring the shunt cap.

Re: WWV, a silent key?
Posted by John Davis on February 20, 2001 at 12:25:58

I wouldn't be too worried about this survey being a prelude to doing away with WWV. Surveys like this have been conducted several times before, with the principal results being changes in the modulation format and the type of information delivered. It's like the Nielsen ratings for TV broadcasters.

However, it's still definitely worthwhile to participate. Broadcasters and hams continue to use WWV for quick frequency calibration; hams, SWLs, and all kinds of field researchers use the solar terrestrial information; and the time itself remains an essential backup resource for navigators and us mere mortals. It never hurts to remind them that we find the service useful...and perhaps there are other kinds of data they should be transmitting as well (alerts about short-lived geophysical phenomena, perhaps?).

73,
John

Re: LEK WOLFing on 186.700
Posted by John Andrews, W1TAG on February 20, 2001 at 13:00:29

Here's the quick results from a 5:30 AM to 6:30 AM EST recording of LEK on Tuesday, 2/20:
-------------------------------------------------
WOLF version 0.21 t: 24 f:-0.090 a: 1.0 dp:105.2 ci:13 cj:362 ???IUIKBRNT EM7 ?
t: 48 f:-0.745 a: 0.4 dp:103.0 ci:14 cj:449 NCI43XKOED/LZ/Z ?
t: 96 f:-0.705 a:-1.0 dp:100.9 ci: 4 cj: 53 L9DF1DA8FGZ*DEP ?
t: 192 f:-0.518 pm: 194 jm:506 S.0IEQ/9XOKK1.6 ?
t: 288 f:-0.439 pm: 253 jm: 67 DP/1*WS2CVLNKAB ?
t: 384 f:-0.439 pm: 388 jm:377 LL E4K6/DMGUNHQ ?
t: 480 f:-0.439 pm: 449 jm:377 A7XHKN5*2OKNNL5 ?
t: 576 f:-0.439 pm: 551 jm:377 JZA.PF87KLREV8F ?
t: 672 f:-0.439 pm: 607 jm:377 N9B3W 1H7C8LFZ1 ?
t: 768 f:-0.439 pm: 645 jm:377 SE8CVV5*2NJDBI6 ?
t: 864 f:-0.439 pm: 647 jm:377 DE LEK AB.J.HUV ?
t: 960 f:-0.439 pm: 659 jm:378 QX4VQO PJ6UQGT/ -
t:1056 f:-0.439 pm: 824 jm:378 HDZ.2IL* 3*UOQ ?
t:1152 f:-0.439 pm: 860 jm:378 DE LEK AITKIN* ?
t:1248 f:-0.439 pm: 899 jm:378 DE LEK AITKIN* -
t:1344 f:-0.439 pm: 970 jm:378 DE LEK AITKIN* -
t:1440 f:-0.439 pm:1009 jm:378 DE LEK AITKIN* -
t:1536 f:-0.439 pm:1059 jm:379 NK7C917FUVA9GRE -
t:1632 f:-0.439 pm:1082 jm:379 DE LEK AITKIN* -
C:\WOLF>
----------------------------------------------------------
Without having had time to play with the file, I believe the signal was best in the 5:30 - 6:00 AM slot.

John, W1TAG

Computer ID Software
Posted by Charlie Vest on February 20, 2001 at 18:08:34

I am currently using Lyle's software for my beacon ID.It works just great but I am interested in using the same computer to ID more than one beacon.Is there any software available to do this ?
THANKS,
...Charlie...KC0EH...

Re: Computer ID Software
Posted by John Davis on February 20, 2001 at 21:38:44

Charlie writes: "...I am interested in using the same computer to ID more than one beacon. Is there any software available to do this?"

I don't believe so. At least, not yet.

Got any specifications you'd like for it to meet? Range of transmit speeds, number of beacons, preferred operating system, comm ports you'd like to involve, etc.?

73,
John

Argo beta 1, build 123
Posted by Alberto di Bene, I2PHD on February 21, 2001 at 09:47:56

Hi all,
many Argo users did complain about the fact that the screen capture facility did not work, or better, it worked incorrectly, when the Argo screen was covered by other windows or a screen saver.

With build 123 this has been corrected. What happens now is that, when the timeout for the capture triggers, Argo pops up for a fraction of a second from nowhere, the capture is done, then the window which previously had the focus (the foreground window) is restored. This also if a screen saver is active at the moment.

There are also some minor improvements. From the Readme :

Beta 1, build 123 (Feb. 21st 2001)
- Screen capture now works even if the Argo window is covered by other windows.
- When reloading saved settings, you don't have to type their name, but just
make a choice in a list box.
- CPU overload indicator now works ok, as the MasterTimer and the DoProcess
routines are placed in different threads. This has also some other beneficial
effects.
- Frequency scale ticks algorithm slightly revised and amended.
- Some code adjustments and error corrections.

Build 123 is available, as usual, from : http://www.weaksignals.com

73 Alberto I2PHD

JDH off the air
Posted by John Hoopes on February 21, 2001 at 20:00:24

Hi All:

Just wanted to drop a note to let everyone that JDH will be off the air until next season. I'm having a problem with wild pigs digging up my yard and my ground radials. I wonder if RF fields attract grub worms because that is what the pigs are looking for and there seems to be an abundance around the antenna. I also noticed the thunder storms are becoming more frequent with each passing day so 24 hour beacon operation will become somewhat of a hazard.

Thanks to all that took the time to listen for JDH and for the signal reports. This has been the best year for me to date. For those of you who will continue to operate, best of luck.

73 John/AB4MS/JDH

Re: wolf
Posted by Lyle Koehler on February 22, 2001 at 23:22:00

Date: 2/22/01 11:12:07 PM Eastern Standard Time To: (Kathy & Nick Nicholson), (LowFER reflector), (Longwave Message Board)

Kathy & Nick Nicholson wrote:
::Lyle, where is the program WOLF available for download ?

http://www.scgroup.com/ham/wolf.html

I have added a short set of notes called "Wolf for Dummies (including me)" to my web page. Kinda redundant, since it's a re-hash of what is covered on Stewart's web site, but it does include circuits for keying an XOR gate modulator from a wolfx.wav audio file.
-- Lyle, K0LR http://www.computerpro.com/~lyle

Earth field detector
Posted by Donald R. Moler on February 23, 2001 at 14:26:31

The earth's magnetic field affects the very low frequencies as well as the rest of the radio spectrum. So it would seem that many of the lowfers and natural radio enthusiast would be interested in a simple method of detecting extremely small changes in the earth's magnetic field and the device I use I will describe here;

The idea is to float a magnet in water with a mirror attached and then reflect a laser off of the mirror onto a distant wall. The laser can be better focused by first shining it through one side of a pair of binoculars if one wants better resolution. I use the end cap from a four inch PVC pipe as the water container. I then mix a small amount of powdered iron with epoxy and place it in the bottom middle of the end cap. This serves to keep the floating magnet centered in the end cap and enables it to rotate freely. Then mount a small front surface mirror and a very small bar magnet or a chip of a magnet in a plastic spray can top, that will be used for the boat. I covered my device with a small fish tank so the air movement would not affect the boat. You may want to add a little oil on the water to keep the water from evaporating. This magnetic field detector is so sensitive it can detect cars going down the street and the refrigerator door opening. In the summer I shine it on the barn about 200 feet away and during a magnetic storm it will move back and forth as much as ten feet or more. I can detect aurora long before it affects the bands. The natural radio enthusiast may want to try and correlate this with radio noise. Don Moler N8BKR Girard, Ohio.
----- Original Message -----

XM(GR) Testing in WOLF Mode
Posted by Les Rayburn, N1LF on February 24, 2001 at 16:24:12

XMGR joins LEK in conducting on air tests of the new WOLF mode. Currently I am transmitting
24/7 in WOLF mode on 184.900khz. Reception reports are very welcome!

RE:XM in Wolf mode seen in EN36US
Posted by Bryce Ofstie, KI0LE on February 25, 2001 at 23:40:33

After a weekend of bad listening conditions the static crashes finally let up enough for me to record Les' signal and decode it with Wolf. At 8:00 PM CST I recorded for
28 minutes and at 1056 seconds into the decode I started seeing XMs. Nice job Les.

This is now the second signal I have seen in Wolf, Lyle's being the first. I can see Lyle's signal anytime of the day and usually within the first 24 seconds of the decode.

With Wolf and QRSS it looks like we may have modes that can be seen through the summer.

73 and good listening,

Bryce KI0LE/BRO

Loop Antennas for Receiving
Posted by Rye Gewalt on February 26, 2001 at 17:58:02

As kind of the new kid on the block, do I get the impression that Loop antennas are the devices of choice for receiving and wire/masts are the most commonly used for transmitting.

I am seeing significantly lower noise using my resonant loop antenna (18T x 4ft/side). I get the feeling that my long wire and tuner make the antenna too close to the house where there's lots of near field junk from the power lines. The loop is away from the house 40 feet and fed with matched coax via a one turn coupling link in the loop antenna.

I'd be interested in thoughts on this....

Regards Rye

Freq change for WA
Posted by Bill Ashlock on February 26, 2001 at 19:47:00

WA has moved up in frequency approx 1.5 Hz to 185.302 to allow a clear frequency for Jim Shaffer's receiving attempts. This may allow others a crack at WA as well.

The QRSS rates are 45 sec dots - even hours, and ~22 sec dots - odd hours.

Appreciate and all signal reports.

Bill WA Andover, MA

Western Canada LF Activity
Posted by Steve McDonald on February 26, 2001 at 23:52:52

Does anyone know of any activity/interest in doing some 2 way LOWFER work out this way. I would love to build up some gear but it would be nice to have someone to work when its done! I think it would be great fun to run some skeds with central BC or Alberta from here. Any takers??

Steve / VE7SL

TEXAS now on WOLF mode 24/7
Posted by Bill Cantrell on February 27, 2001 at 01:10:39

Date: 2/26/01 10:56:26 PM Eastern Standard Time To: ('LowFER Reflector'), ('LWCA News')
CC: ('Lyle Koehler')

Hello All,
I am now running the TEXAS Beacon in the continuous WOLF mode with many thanks to Lyle for a WOLF EEPROM. I am on 189.090 kHz. The carrier frequency and keying are accurate to within +/- 0.3 parts per billion. My antenna current is doing good right now, despite damp soil conditions.

Regards,
Bill EM12hw Haslet, TX
"TEXAS" & WD5CVG

Re: Loop Antennas for Receiving
Posted by John Andrews on February 27, 2001 at 09:20:06

Rye,

In moving the antenna away from the house, you are certainly gaining some isolation from the electrical and electronic garbage we all seem to have. But maybe more importantly, your receiving setup is now more isolated from the noise and junk that is flowing through the ground. Your wire antenna needs a good ground system under it in order to receive desired signals. But when you consider all of the noisy currents that flow through that ground area, you realize that they can easily contaminate the signals you are trying to hear.

By your description of the loop, on the other hand, the loop itself has no direct ground connection. You are inductively coupling to it with your 1-turn link. I'm guessing here, but typically that may only be grounded at the receiver end. Some of us use ferrite-core transformers before the receiver that "float" the ground connection on the coax to the loop, and find that further quiets things down.

There's a good article about all of this on the LWCA site:
http://www.lwca.org/library/articles/wa4ghk/gnd_isol.htm

With all of the new weak-signal detection techniques, it's amazing what you can "hear" from noisy suburban locations. But it's certainly worth the work to quiet things down as much as possible.

John Andrews, W1TAG

Re: Loop Antennas for Receiving
Posted by Rye Gewalt K9LCJ on February 27, 2001 at 15:46:29

Thanks for the comments and it indeed makes good sense, particularly since I get different noise levels depending on which of several grounds I use. I do have the loop ungrounded and have been trying a broadband video isolation transformer with mixed results. I am just about to add a preamp to the loop ---mostly so I can tune the darn thing remotely. It's all of 5KHz wide at 6db Points and I think maybe a bit too loosely coupled. I'll probably try the preamp (the LEK single ended one) directly to the loop and also to the coupling link as time allows.

I did have one interesting event last week. We had a power failure in the area which at first was irritating until I realized that the noise level would probably be down. I quickly hooked a battery to my AR3030 and took a listen. At 4 in the afternoon I could clearly hear TH up in New Jersey and DCH (Berlin MD)(I think I have that right --- memory goes second) here south of Washington DC. I wish the outage had lasted longer as I would have liked to have made some measurements of comparative levels, but it was over too quickly. You could hear the noise level rise about ten seconds before the power came on so I suspect I was hearing other areas coming up just before we came on line.

It was interesting to note that most of the noise that I have is not really synchronous with the power line -- I built a synch. blanker for that and it works good (actually great!) --- but the majority of the residiual "city" noise appears to be very random with little obvious relationship to the line (using a scope synched to line and displaying IF out). I suspect some work with a FFT would find more 60Hz stuff in the noise----. Research for later-----

Great fun this....

Regards Rye Gewalt K9LCJ

Antenna loading coil
Posted by Lewis Denton on February 28, 2001 at 12:41:37

I have completed my LOWFER xmiter and have a 50 ft.vertical center loaded. could some one direct me to a site where i can find loading coil spect. to go between xmiter and antenna.
Thanks Lewis WA4LIP

Several questions from LW novice...
Posted by Joel Govostes on February 28, 2001 at 19:51:13

1. Are QRSS LOWFER signals intended for copying by computers, or by listening, or both?

2. I have seen designs for multiturn loops, using a single turn loop within the perimeter of the larger one to couple to the rcvr itself. Why just a single turn on the pickup loop? Is the pickup loop (not sure if that is the correct term) intended to create a proper match for a coaxial cable lead-in, presuming that is what is generally used to run the signal to the receiver location?

3. Do most LW dx'ers (esp. looking for LOWFERs) use preamplification, as in VHF/UHF weak-signal work, or do they merely rely on the gain and directivity of the loop antenna?

4. Finally, what is the point behind "shielded loop" designs? Why doesn't the shielding interfere with (or
"block") the desired incoming signal or prevent it from developing current in the inner loop itself?

Thanks for any comments or info on these topics. So far I have only used a passive box-loop (on big cardboard box!), setting my portable rcvr near the center of the loop, and resonating the latter with a BC variable cap. So far have only logged ZWI in Syracuse, NY (I am near Ithaca), but that alone was encouraging, and I am hoping to snag a few more once set with a less makeshift antenna! I do believe the bug has bitten, tho'.

Thanks/73 Joel N1AEP jwg6@cornell.edu

Re: Several questions from LW novice...
Posted by JG on February 28, 2001 at 20:04:05

BTW - I have logged several MW NDB's, but the Baldwinsville, NY LOWFER is the only LOWFER so far. Rcvr is hardly much good for LW -- a Sangean ATS818. So maybe not bad for starters, considering that handicap...
73

Re: Several questions from LW novice...
Posted by John Andrews, W1TAG on February 28, 2001 at 20:49:46

Joel,

I'll give your questions a shot. More experienced folks here may want to chime in.

1. Are QRSS LOWFER signals intended for copying by computers, or by listening, or both?

It's difficult to copy QRSS CW by ear, but not impossible. The real advantage to it comes when you run a DSP-based program such as Argo or Spectran, and work visually in a narrow bandwidth. You can then copy signals that might not be audible in the noise. The narrow bandwidth and long detection times are the keys, here. Some of the current activity is with very slow speed cw -- things like 60 second dots. NG by ear!

Yes. Think of it like "link coupling" in conventional transmitter and receiver circuits. If you parallel tune your loop, and connect your 50-ohm receiver input right across it, you will swamp that tuned circuit, destroying the Q, and losing signal level. On the other hand, a one or two turn link will transfer the power more efficiently into the low 50 ohm load, and the Q will be less affected. The link approach has a secondary advantage in that the tuned loop is usually left floating with respect to ground. This reduces noise pickup, and makes the pattern more of a standard fat figure-8. Another approach would be to series tune the loop into a small coupling transformer (1:1) and connect the coax to the secondary of the transformer.

3. Do most LW dx'ers (esp. looking for LOWFERs) use preamplification, as in VHF/UHF weak-signal work, or do they merely rely on the gain and directivity of the loop antenna?

As far as I know, most use preamps. Some put them outside at the antenna, others keep them in the shack. Most of our receivers can use the help. Because the loop is fairly sharply tuned, you are less prone to the overload effects you may be used to at HF. But the preamp still has to be "sturdy" enough to endure the local AM broadcast, Loran-C and other signals that make it through. The preamp would be a necessity if you do not use the single turn coupling method you mentioned. In that case, the preamp would be required to present a high impedance to the loop, and drive a 50 ohm line with the resulting signal.

First, the shield cannot be continuous around the loop, or it WILL short the signal out. So, shielded loops have a break in the shield, usually at the mid-point. Shielded loops are useful in reducing precipitation static, such as on the outside of airplanes. Many claims have been made over the years that the shield reduces all forms of electrical noise and cleans up the pattern of the loop. The reality is that you are probably better off with skipping the shield, and keeping the turns farther apart (reduces capacitance between turns so you can have more of them). You are definitely better off if you keep the loop electrically balanced with respect to ground, with or without the shield. I am using a 14 turn square loop, 6 feet on a side, with the turns spaced one inch apart. Runs circles around anything else I have tried.

But you've copied ZWI, and I haven't been able to hear him in central MA. You should also try for RI on 184.32. He's running QRSS, so either slow your brain down, or start playing with the computer!

John Andrews, W1TAG

www.lwca.org

potrzebie