new radio noise on HF ??

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  • Updated 3 years ago
The last month there has been an annoying wide-band RF noise on my QTH
  The noise is recorded on a flex radio 6500th

  see the noise here:

  The question is whether it is a completely local noise or if there are others who are experiencing something similar.
  Does anyone have a guess at where the type of noise can come from?

OZ1OP, Denmark
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ole puschl

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Posted 3 years ago

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Photo of WX7Y


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looks like you have a switching Power supply / WALL Wart or something gone bad or possibly other switching device or Solar charge controller or the like.
This is Local I would think  

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I had a somewhat similar interference. The root cause was a corroded connection at the mains power input panel, before the breaker panel on the power company side. What really complicates this type of common mode noise is that other radiators will piggy back on the signal. In my case, my MorningStar charge controller caused a signal to ride on the mains generated noise. The power company fixed the mains problem but only when it got so bad that the input voltage was falling to 80-60 volts. The problem caused our computer battery back up to sound a low voltage alarm. Checking the AC leg we saw the big time voltage sag.

The solar charger issue was taken care of by replacing the MorningStar with a Midnite Solar charge controller. I tried getting MorningStar to help but their tech support blew me off. Researching the replacement charge controller, I spoke with Midnite Solar BEFORE I bought their unit. They do a lot of RFI testing and were very confident that their unit was quiet. They were 100% correct.

I used an MFJ-852 noise sniffer to verify the noise was coming from the power company input but only after the root cause was found with a volt meter. What complicated things was that the crappy solar charge controller noise "hid" the bigger problem of the powe company issue when Imwas sniffing for radiated noise. Once I replaced the charge controller, I was able to eliminate "local noise" in my environment and was about to sniff noise at the power poles.

I did scope for common mode noise on my house outlets, but the commercial property we were on had two phases coming in and my local outlets were on the second "good" phase. It was a coincidence that we started having the low voltage alarms a day or so after Imreplaced the solar charger. Once we identified the voltage sag, when I checked at the panel with the MFJ there was a strong radiated signal at the power company panel.

Bottom line, noise issues are very complicated and you need to start with your close environment and then keep looking for other noise sources.