Re: [IRCA] How to ID an unmodulated LW carrier?

[Stephen Airy <pianoplayer88key@xxxxxxxxx>]

Oh ok, that sounds quite likely.  I plugged their coordinates into the FCC's distance finder and I'm about 18.5 miles away at a heading of 69°, which seems to match the direction I was aiming for the strongest signal.  It wasn't demodulating at all on my AM PL-606 - it sounded just like a broadcast signal does when it has just an unmodulated carrier with no program content, just a lot narrower when I tuned off frequency (if it makes any difference with non-modulation).  Anyway I looked up the coordinates on Google Maps, and it appears to be in the area where the Point Loma lighthouse is.
And yes, I'm wanting to build a loop (or a few) sometime.  I'm just not sure what type of frame I want to use, yet.  I know a crate loop is out of the question due to needing to keep it a reasonable size and make it collapsible.  I've been considering a PVC frame loop like in Gary DeBock's articles, but when I was mentioning the idea to my dad, he thought the PVC wouldn't hold up as well in our weather here, where it can exceed 100°F with low humidity in summer.  
 
Also I'd need to figure out what type of capacitor to use.  (It would definitely be one of the larger types like what Gary uses in his projects, not the little cheapies that come with analog-tuned AM and FM radios.)  I'm just wondering if there's a way to get a better shape factor (flatter top, steeper sides, greater total off-frequency attenuation) by using a double or triple-gang capacitor in the design and 2 or 3 coils accordingly?

From: Steve Ratzlaff <steveratz@xxxxxxxxxxxx>
To: Mailing list for the International Radio Club of America <irca@xxxxxxxxxxxxxxxx>
Sent: Saturday, August 20, 2011 5:22 PM
Subject: Re: [IRCA] How to ID an unmodulated LW carrier?

You are possibly hearing a DGPS station on 302 kHz; there's one on 302 located at Point Loma, CA--don't know where that is in relation to you.
http://www.dxinfocentre.com/dgps.htm has info on frequency and locations of NA dgps signals. DGPS generally run around 100 watts and generally use good antennas, compared to the usual 25 watts and often poor antenna that NDBs use, so the DGPS can be a pretty strong signal depending how far you are from it. (Or use Google to find out what DGPS is if you don't know anything about it.) I'm not sure what DGPS sounds like on an AM radio, if it demodulates it at all; a radio with SSB or CW mode you hear the "rattle" of the distinctive radioteletype-type signal. There are various software decoders that can be fed with the audio output from a radio receiving the signal which show the location and other information about the DGPS signal, however a ULR is not a suitable radio for use with such software.
If you can solder two wires to a variable capacitor, and wind wires around a PVC loop frame (or other type of loop frame) you could make your own inexpensive tuned LF loop, and inductively couple your ULR (or other radio that uses a ferrite loopstick at LF) to that. There are various loop calculators on the internet where you can design the loop given the frame size and desired frequency.
73,
Steve

----- Original Message ----- From: "Stephen Airy" <pianoplayer88key@xxxxxxxxx>
To: "IRCA List" <irca@xxxxxxxxxxxxxxxx>
Sent: Saturday, August 20, 2011 3:35 PM
Subject: [IRCA] How to ID an unmodulated LW carrier?


Hi all...

I briefly checked some LW reception around sunrise this morning using my Tecsun PL-606 resting on a barbed-wire fence across the street from my house.

I came across an interesting signal on 302 kHz.

73 and good DX,
Stephen

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