I don't usually operate in 2 m, save for FM satellites. I usually go to a nearby park when I do this, for better view of the horizon. But I tried working them from home for the past couple of days, and found there is massive QRM around 145.650 MHz. So strong, I can hear it on my handheld with the antenna detached. It sounds like a motor.

With the SDR, with no antenna attached and the input gain set to zero, I see it at -45 with a noise floor of -60. The signal looks like a hump with the sides wobbling left to right (as if you were rocking a glass of water on a table). Yesterday, it looked like this:

enter image description here

This QRM appears all around the neighborhood. It's difficult to pinpoint since it's so strong (it's so strong I don't need to open my squelch to hear it).

The signal stays mostly at 145.650 but from time to time it shifts up and down. Yesterday it was at 145.850.

What on earth could be causing such strong interference? Could it be power line related?

Power here is 220 V 50 Hz. Overhead 220 V wires and buried 13.2 kV lines. On HF I have the usual S7 to S9 city noise.

I was able to take a screen capture of SDRsharp during the two "moments" the noise has.


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    $\begingroup$ Maybe you should use fox hunting techniques to discover the origin of the signal. $\endgroup$ – rclocher3 Mar 10 '20 at 13:30
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    $\begingroup$ Is it just a carrier (i.e., just quiet?) Cable TV leaks will cause those. If you're lucky and can find a tech for the company who (a) knows what you're talking about and (b) cares (and good luck finding one), you can get that fixed. $\endgroup$ – Duston Mar 10 '20 at 14:01
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    $\begingroup$ @rclocher3 the problem is that the signal is so strong, I can hear it without an antenna. $\endgroup$ – hjf Mar 10 '20 at 14:25
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    $\begingroup$ @hotpaw2 the noise appears on 3 different radios: a RTL SDR, a Baofeng, and a Yaesu FT60. $\endgroup$ – hjf Mar 10 '20 at 18:02
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    $\begingroup$ What's the oscillation period left to right ('glass of water' analogy)? $\endgroup$ – user124039 Mar 11 '20 at 14:52

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