A very strange occurrence....

[Allen B]

I sometimes run JS8 call on 11m. A few times now I have shut down my radios (power supply disconnected from wall), but my SignaLink is still on. Yesterday I left for work and still received a whole bunch of 11m meter activity. A couple of weeks ago I had no radios on my desk and just the SignaLink was sitting there, it was on but the audio wasn't connected to anything and I still received some activity. After looking up the call-signs on pskreporter I find that they were on 20m. That's with absolutely no radio whatsoever! This is a repeatable thing, I will do it again today and post a screenshot later this afternoon of what I get today.

My question would have been, "Is it possible for a radio to somehow still decode or rectify a signal when off?" I would have though SSB would need a local oscillator running. But then what explains the SignaLink picking up 20m signals from half way across the country? None of this activity I see with no radio is local.

Very strange.

 

[Eldorado828]

 

[TM86]

There's most likely a PN junction somewhere in the SignaLink acting as an RF detector. Since you say the audio side wasn't connected to anything when receiving the 20m signals then the USB cable or power cord is probably acting as an antenna. Could be both for all I know.

Maybe get some RFI suppression ferrites and run the various cables through them and see if that stops the mystery signals? Might work, might cost you a few bucks only to have the mystery deepen.

 

[Rwb]

View attachment 61519

ET is close by petting ALF

 

[Allen B]

Ok so here was 24hrs or so of no radio hooked up. Most of it was garbage but you can see callsigns and even the CQ call at the top.

 

[Allen B]

There's most likely a PN junction somewhere in the SignaLink acting as an RF detector. Since you say the audio side wasn't connected to anything when receiving the 20m signals then the USB cable or power cord is probably acting as an antenna. Could be both for all I know.

Maybe get some RFI suppression ferrites and run the various cables through them and see if that stops the mystery signals? Might work, might cost you a few bucks only to have the mystery deepen.

I actually do have ferrites on all the cables at the back of the SignaLink. So I guess now the mystery deepens.

 

[TM86]

I actually do have ferrites on all the cables at the back of the SignaLink. So I guess now the mystery deepens.

Hmmm... It may just be possessed by the spirit of a ham who has passed on and misses making contacts. Take it with you to the next hamfest and give it some coffee and donuts, see if that calms it down.

 

[Shadetree Mechanic]

That does sound strange, almost like there is an SDR built in. Or a glitch in the matrix.

 

[Rwb]

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