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Post by bluebucketradio on Nov 24, 2015 21:34:11 GMT
This was posted yesterday on facebook and i thought it would helpful to others to see this guy's design. It is a beacon on 22 meters operating on 13.355.8 Mhz with something close to 4 mW. I might have received this beacon as well, i couldn't hear it on my Grundig G3 but using the Chilton online receiver I was able to hear something that resembled this beacon according to the video included in the article. Link to article.
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Post by Admin on Nov 25, 2015 1:21:31 GMT
That's a nice little TX. I have a 13.560 4 pin IC oscillator which just needs the PA and modulator so maybe this circuit can be adapted to it.
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Post by bluebucketradio on Nov 25, 2015 2:57:06 GMT
Unless my morse is worse than i thought , this might be his signal received on the Chilton Online Shortwave Receiver in Reston Virginia, AA7EE Dave Richards the builder of this transmitter lives in Oakland, California. Link to audio file recorded from the Chilton Online Shortwave Receiver
The i.d. he sends is SPT. Very nice transmitter though and not too big either. I tried to hear this on my Grundig G3 but the noise level in the house from wifi is insane and it's too cold to go outside. Barry of Blue Bucket Radio 1520 AM |
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Post by Deleted on Nov 25, 2015 14:22:53 GMT
WOW THISis an interesting thread... I was just about to start a thread on SPEED OF RADIO, which I will do in a minute... but this subject of part 15 operation in the 15.560 neighborhood appeals to me a lot. Barry, many thanks for sharing the links... the transmitter looks like a carefully planned and high quality unit. This month and next I am installing my Big Talker shortwave circuit cards into a metal case and installing an End-Fed Dipole Antenna outdoors, then KDX-SW will be on the air full time at 13.560 MHz. Seeing the nice wire-wound toroids reminds me that the Big Talker needs to have its little output filter inductors replaced by toroids. "Toroids" always sounds to me like a medical condition. LINK TO BIG TALKER PROJECT
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Post by Admin on Nov 25, 2015 22:32:12 GMT
Hmmm. I couldn't quite make out the code. Sounds like a subaudible tone with frequency shift keying.
I could tell when the signal was present but not really hear the audio.
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Post by bluebucketradio on Nov 26, 2015 5:05:04 GMT
MRAM1500,
I had a hard time too, there might be two carriers in there. It sounds like two carriers only when the beacon kicks on then the mixing of two carriers distorts the actual message being sent. It is a shame I couldn't get this on my Grundig G3, at least it could have given me some kind of idea what was going on.
It has a cheap lcd meter, it would have something to gauge the actual signal strength.
I can tell from listening to it, the beacon was just barely making it above the noise level.
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Post by Admin on Nov 27, 2015 5:07:37 GMT
Curious to know if the beacon "keyer" is modulating the carrier or just keying it on/off.
Did the radio receiving the signal have a BFO? If so I would think you'd hear a second signal when the beacon was not transmitting.
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Post by Deleted on Nov 27, 2015 23:09:56 GMT
Nothing Heard Here
Whenever this topic of 13.560 comes up I go over to the Sangean ATS-505 and give it a listen.
Only one time did I ever hear a far off tone about 3 kHz. Unable to detect any identifier.
Just now I tried again but only get fuzz-noise coming from the Big Bang.
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Post by thelegacy on Nov 28, 2015 0:46:06 GMT
I heard something a few days ago on 15.560 and I thought it could be a beacon but was not sure. Nice that these little transmitters could get out on SW. Makes me want to try an Album Rock station down there and see what happens. Could be interesting.
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Post by bluebucketradio on Nov 30, 2015 21:50:05 GMT
MRAM asked: "Did the radio receiving the signal have a BFO? If so I would think you'd hear a second signal when the beacon was not transmitting." The Grundig G3 has AM-Synchronous as well as SSB and rather cheap clarifier tuning., I didn't think to try that since the radio is horrible on SSB. Honestly, this radio from Grunding has to be one of their worst designs. I need to take it apart and clean it again as the buttons are dirty. For example if I press the channel up or down button, other functions that are not assigned to the channel buttons activate such as page or ssb functions. I don't know why this has become a problem other than living in a damp area, could be a design flaw. This radio when not all gummed up is a good performer but nothing like the Realistic DX 390 which is a re-branded Sangean radio i no longer own. Might have to buy another DX 390 on Ebay. Grundig G3
Realistic DX-390 |
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