The AM Forum

 Hello: I have a ON and OFF buzzing noise on my receiver ON 5 seconds OFF 5 seconds almost all day. It seems to be mainly on the 40 meter band and up higher. I think it is local but don't know. What is a good portable receiver that is made to hunt down interference like this.

John W9BFO

Maybe whatever this guy is using

https://www.youtube.com/watch?v=xLKq0hgKn9o

He is using a low cost Tecsun receiver with a single turn coax loop antenna on a tennis racket, tuned right to 20 Meters. Likely in the AM mode.

The solar panels are not making the noise. Likely the battery charge controller is the culprit. Some are very noisy and some are mildly noisy, but all can benefit from snap on beads like #43 types located close to the controller as possible on input and output and even the battery leads. Depending on the wire type, it may take a toroid type or a large bead and wrapping a couple of turns through it. I big braid going to a ground rod would also be a nice touch connected to the case of the controller. The plastic PWM controllers are a mess. The MPPTs can be bad too.

I had a buzzing that was coming from a street lamp down 2 houses that the power company fixed and bingo - no noise.

There was also a commercial company doing arc welding that made a racket from quite distance away.

Pool pumps and heaters are another "newer" source of noise.

It has been shown that a solar panel, with nothing connected to it, can contribute to the ambient noise level.

These panels ARE considered defective.....  But they still work and provide near full power output, so it's pretty hard to tell.

And the noise level can also be attributed to either microinverters or power optimizers.


--Shane

Hello: Thanks for the info on the receiver I am going to have to get some thing I sure have a lot of noise on  my block. Where can I find one of those TECSUI  receivers?

John W9BFO

How do you know that its not coming from your house ?  Have you shut off the main breaker and verified on a battery operated receiver that the noise is still there? 

With all the things that have internal UPS we never think about, shutting off one's main breaker doesn't alwatlys kill all electronics, either.

Quite a few of the voice over internet / fios / etc boxes will stay powered up when power fails.  Switching converters just buzzing away.

Tecsun can be purchased via eBay, Amazon, and either HRO or R & L I believe has them.

A NanoVNA can also be used.  Sweep in the range you hear it, S21.  Put the 50 ohm load on the S11 port and an antenna on the S21 port.  Bam.  Uncalibrated Spec An.

--Shane
KD6VXI

Hello: I have turned off any device that could make noise, with out the outside antenna on the buzz is gone. Thanks for the tip on the receiver I may purchase one, I live about one mile from the local hospital and I think it maybe the strobe lights coming on for the life flytes landing.

Thanks for all the help

John W9BFO