[RFI] AM Broadcast Intermod?

[donovanf at starpower.net]

Hi Pete, 


The primary rule when tracking down any RFI or intermod source is 
to turn off all power in your home and all UPSs. This includes UPSs 
that are easily forgotten such those integrated into tele phone, 
laptop computers and network equipment. Its also wise to disconnect 
all antennas and control lines to your station. 


Only after you've completed that basic first step does it make sense 
to start looking outside your home. The same applies to intermod 
from external emitters and buzzing harmonics of your own transmitted 
signal, all of which can be caused by devices in your own home. 


73 
Frank 
W3LPL 


----- Original Message -----

From: "N4ZR" <n4zr at comcast.net> 
To: "RFI List" <rfi at contesting.com> 
Sent: Tuesday, January 28, 2020 5:05:53 PM 
Subject: [RFI] AM Broadcast Intermod? 

I'm embarrassed to admit that I had overlooked a noise-maker in my 
shack, my 1 TB USB disk drive. I cleaned that up with a few turns of 
the DC power cable around a type 31 toroid, and now I've uncovered 
something under it. It's a wideband signal (tuning makes no 
difference), but sounds very much like a badly distorted broadcast station. 

Just on a hunch, I tried tuning across the AM broadcast band, and found 
a loud AM sports radio station on 1570 KHz that appears to be 
broadcasting the same content - pauses, pitch of voices, etc. all seem 
to match.. Unfortunately, just before I could get set up to record, the 
voices on 160 suddenly went away. I'm assuming they'll be back, and 
while I wait to get a recording I'm wondering: 

* Does this sound like intermod, or some other phenomenon? 

* Is it the result of something wrong at the station? 

* If so, how best to approach them about it? 

-- 
73, Pete N4ZR 
Check out the Reverse Beacon Network 
at <http://reversebeacon.net>, now 
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