[Cliffdwellers] QRM on HF

[Terry Conboy]

At 04:13 PM 2004-11-22, Walter Cang wrote:
>I checked the radio and it seems that the peak noise level is every 10khz 
>ending on an 8.  Ex. 14.218, 14.228, 7.008, 7.018, 21.218, 21.228, etc.
>
>The sound is heard over a spread of about 2 khz. above and below it.  My 
>PC is in another room although the loop runs above it in the ceiling.  But 
>then the sound is still there despite shutting it off so I'd rule that out.

You may want to try a different receiver and see if your rig itself is the 
source of the noise.  The frequency displays on some radios emit RFI which 
is especially noticeable with nearby loop antennas.  The fact that the last 
"8" digit is involved is quite suspicious, since all of its segments are 
illuminated.

My ICOM 765 display puts out noise.  At a previous QTH, it was audible, but 
not too loud, when I used a 1-wavelength loop antenna with one corner just 
outside the third floor hamshack window.  (It was connected via a short 300 
ohm feedline and balanced tuner.)  An AM radio brought near the display was 
a good sniffer.

73, Terry N6RY