eHam

eHam Forums => Elmers => Topic started by: KC8EQF on March 31, 2023, 11:52:24 AM

Title: Electrical noise
Post by: KC8EQF on March 31, 2023, 11:52:24 AM
I have a ATS-20 receiver plagued by "frying bacon Sound" electrical interference. How is the best way to remove this noise?
Title: Re: Electrical noise
Post by: K6SDW on March 31, 2023, 12:01:39 PM
Try to find the source of noise...one culprit is power line electrical noise.

GL/73
Title: Re: Electrical noise
Post by: K0RS on March 31, 2023, 12:10:28 PM
There probably isn't a good solution to this other than find the source of the noise and eliminate it.  Most modern amateur transceivers have noise blanker circuits that are pretty effective on this type of interference...something the inexpensive ATS-20 lacks.  One could always add an external DSP to the audio output like a Timewave DSP-599 or DSP-59+, but the outboard processor would likely cost more than the radio and it still wouldn't be at the IF stage.  Try some detective work to try to track the noise source down.  Power companies can sometimes be helpful if you can convince them the noise is their responsibility.  Unfortunately RF noise is becoming more and more ubiquitous so you may have a challenging task.
Title: Re: Electrical noise
Post by: WA3SKN on March 31, 2023, 02:57:57 PM
If you remove the antenna and put a short on the jack, do you still have the noise?  Then the noise is external to the radio.  Do you still have the noise when NOT in FM mode?  Is this in all modes?  All frequencies?
Finding the source may be difficult, since the info claims the external antenna is for FM use only.

-Mike.
Title: Re: Electrical noise
Post by: NA6O on March 31, 2023, 05:14:22 PM
Welcome to our modern world, saturated with RFI sometimes to the point of incapacitation. Post specific questions in the RFI forum. But start by reading the resources at  http://www.arrl.org/radio-frequency-interference-rfi  Basically, you have to work through a process that locates andidentifies sources of RFI and then attempt to mitigate those. It can be a long journey…

Gary NA6O
Title: Re: Electrical noise
Post by: KC8EQF on April 03, 2023, 04:30:14 PM
I have a ATS-20 receiver plagued by "frying bacon Sound" electrical interference. How is the best way to remove this noise?
I fixed the problem with a good ground and ferrite snap ons but, the problem remains on the low bands.
Title: Re: Electrical noise
Post by: W1VT on April 03, 2023, 04:37:52 PM
The impedance varies as the square of the number of turns.
10 to 15 turns on an FT-240-31 or FT-240-43 ferrite core may be needed.  31 is better but 43 is less expensive.

It the wires are thin I'll use one core for multiple wires.  Such as the mouse and keyboard cable through one FT-240-31.
Title: Re: Electrical noise
Post by: W9IQ on April 03, 2023, 04:44:52 PM
The impedance varies as the square of the number of turns.

This is only true for a low number of turns and then it only applies to the inductive reactance, not the impedance magnitude. The core has a complex permeability that exhibits resistance as a function of inductive reactance. As a result, impedance magnitude is not a direct correlation to the number of turns.

- Glenn W9IQ

Title: Re: Electrical noise
Post by: N4NYY on April 03, 2023, 09:38:56 PM
You are not going to believe this. At Field Day last year at our club, a electrical buzzing was killing 80M phone. I took restored 1965 Sears 100 mW CB walkie talkie with the antenna retracted, and found 2 sources of noise within the Clubhouse. Both switching power supplies wall wart style. And the only reason I brought them was to show the build quality and test their function after being restored. IOW, they were supposed to be eye candy. But they led us tight to the noise. Any 100 mW superhet walkie talkie should work.