[RFI] 40 M QRN

Ash Thornton thorntonash at comcast.net
Wed Feb 11 15:29:40 EST 2009

I have been watching the various discussions, but not sure I have  
seen the situation I an experiencing.

I notice a very wide band QRN situation which is very noticeable on  
CW with a 500Hz filter, usually S 3 spanning up and down the  
spectrum. It often rises to S 5 or S 7 for short periods. On AM it is  
a very fast buzzing noise. I use a 4 Square and usually it is from  
the south, but not always. On a horizontal it is also there and same  

It also shows up on 80 M, but the noise is higher there and I do not  
operate as much 80 CW.

After dealing with this for several years it makes me think it could  
be a TV as the times could mirror watch TV at breakfast and the even  
and more so on the weekends. Certainly could be something else. I  
have had not luck trying to pin it down with an Icom HF handheld,  
does not register on the Icom.

The noise blanker does not affect this QRN. Taking out a preamp helps  
a bit.

Not sure it is the same noise, but at times it appears to roll down  
the band, at least by tracking it on the S meter. Sometime sthe noise  
sounds like a carrier on AM, could be a different source.

I am looking for ideas given walking around with the small HF  
receiver does not show anything?



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