Re: CW Noise Pedestal

Rob Sherwood

There is a known noise pedestal caused by the cooling fans coming on.  This was supposedly solved in production by adding some electrolytics in the DC fan circuitry.  

I ran into a similar noise problem from the DC fan in my now discontinued IC-781 cooling kit. I had to use an R/C decoupling circuit to keep the noise from getting back into the radio’s 15 volt supply. 

Rob, NC0B

On Jan 12, 2020, at 12:07 PM, Bob McGraw - K4TAX <rmcgraw@...> wrote:

I suggest your find one of the remote SDR's somewhere here in the country and listen to it yourself.    Or use a second receiver suitably protected from overload and listen to it yourself.

Make sure the radio ground terminal is bonded back to the station power supply ground.  I find that the DC Neg is not adequate to accomplish this and thus allows the radio to float up from ground by the resistance in the DC negative circuit. 


Bob, K4TAX

On 1/12/2020 10:22 AM, wb6bee wrote:
I have been told by at least two other stations that I have an intermittent 2.5 khz (minimum) noise pedestal on CW.   Sounds like key clicks according to them, but a bit different.   Without hearing it myself, it is difficult to describe.   The issue is intermittent, they will hear it for a while and it will then be gone.   

I am running the K3s.  I key with a bug.   I have the KPA 1500.   The noise is heard with strong signals, although I dropped to barefoot this morning and the listener said he could still tell they were there.   

At first, we thought an RFI issue.   But, if running barefoot, not likely.    

Any comments/ideas


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