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Beeping RF interference with harmonics




 
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Author Topic: Beeping RF interference with harmonics  (Read 1085 times)
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ka1tdq
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« on: January 11, 2020, 11:07:33 PM »

Anyone know what this might be?  The lowest frequency that I spotted it on was 1.75050 MHz.

https://www.youtube.com/watch?v=_Knsuk36Iu4

It has harmonics on 80, 40, 20 and 10 meters. Ordinarily I wouldn't mind because I would just avoid those few frequencies, but my SDRplay 2 has a difficult time with the strong signal and I can hear ghosts of it all across the band.

I could probably upgrade to the latest version of SDRplay that supposedly takes care of this problem.

Jon
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W2PFY
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« Reply #1 on: January 12, 2020, 01:04:39 PM »

I heard a sound just like that coming from my 1988 Chevy pickup truck computer. It was always on and the counter frequency only increased when the engine was turned on. Nowadays I kind of gave up on trying to identify strange sounds with all the electronic garbage being generated by our modern world. Did you try unhooking the antenna to see if it goes away or not?
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ka1tdq
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« Reply #2 on: January 12, 2020, 01:15:17 PM »

I did try the other antenna port on the SDRplay and it's still there. The Icom 7300 hears it too, so it's something real out there.

I live in city limits so it's probably nearly impossible to track down. And really, why bother? I guess as hams nowadays, our task is to try to stay ahead of all the trash with software tricks.

I guess a purchase of the new version of SDRplay is in my future.  HRO is currently out of stock of them by the way.

Jon
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kd1nw
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« Reply #3 on: January 12, 2020, 03:36:11 PM »

Hi Jon,

It sounds similar to, but not exactly like my kohler generator. I think it's the battery charger. Strongest from broadcast up to about 5MHz. 160 meters is pretty much unusable. Maybe someone close by got a new generator for their house?

73 Kevin
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WA2SQQ
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« Reply #4 on: January 13, 2020, 08:13:57 AM »

See how far from your home you can hear it. If its definitely local than get that SDR PLAY into portable mode ansd start hunting the local area. I had something very similar that turned out to be one of my Uniden scanners. Every time the local PD would key up, it would stop - that was the the key to finding it.
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n1ps
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« Reply #5 on: January 13, 2020, 07:29:36 PM »

this is how I tracked an RFI source in the northeast:   
https://www.youtube.com/watch?v=YloNh4EV2PE&t=1s

SDR receivers are really helpful in tracking down noise.

Peter
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ka1tdq
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« Reply #6 on: January 14, 2020, 07:56:31 PM »

Wow! That wiped out the entire 75 meter band at times. Did you inform them of the problem, and did they do anything about it?

Jon
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« Reply #7 on: January 15, 2020, 08:28:42 AM »

What antenna are you using to do the RDF?
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n1ps
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Zorch!


« Reply #8 on: January 15, 2020, 07:00:24 PM »

Wow! That wiped out the entire 75 meter band at times. Did you inform them of the problem, and did they do anything about it?

Jon

Yes they quickly responded and made changes to get the transmissions off the 75M band.  So all is well now.  This RFI had been plaguing the band for months.
Peter
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n1ps
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« Reply #9 on: January 15, 2020, 07:02:40 PM »

What antenna are you using to do the RDF?

I used a marine RDF that had the 80-75M band in it. 

Peter
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