TopBand: Topband BC Stn. Birdies

[Daniel J. Flaig]

David Kennedy wrote:
> 
> I have read, with considerable interest, most of the theories
> about how the gaggle of BC station sigs are generated and
> heard EVERY 10 Khz across the 160 meter band. I think there
> is no doubt these sigs are mixing products (910 + 820 = 1830,
> etc.) but I tend to reject the idea that these sigs are somehow
> generated by diode detection due to corrosion in tower joints,
> down spouts, power lines, Beverage antennas or some other
> mysterious outside source in the neighborhood.
> 
> I feel that one of the top banders might be close to the right
> answer when he suggested that the culprit diodes might be in
> our receiver front end band filters. In discussing this subject
> with Rip, W4FX, I suggested this theory was N.G.because my
> external receiver preamp amplified these birdies along with
> everything else, QRN, etc. Rip replied "How about the
> 3-element diode (transistor) in your preamp?"
> 
> So far I have not been able rebut this explanation. The birdy
> signal strength varies greatly as I switch from one Beverage
> antenna to another. With 7 2-wire Beverage antennas I have 14
> directions available. The birdies peak at random in many
> different directions. Isn't it possible that our state of the art
> receiver front ends are acting like broadband crystal sets acted
> 60 years ago when we were thrilled at hearing the local BC station
> with no batteries? Can anyone think of a fault in this theory?
> 
> Merry Christmas. 73, Dave--N4SU
> 
> 
> 
> --
> FAQ on WWW:               http://www.contesting.com/topband.html
> Submissions:              topband@contesting.com
> Administrative requests:  topband-REQUEST@contesting.com
> Sponsored by Akorn Access, Inc & KM9P
Dave,I had a problem with a dirty connection on my 80 meter dipole that
cause a mixing spur to pop up on 3500 Khz. A clue that it was not
internally generated was that the signal didn't disappear when 30 db of
front-end attenuation was put in,I would have expected the spur to
disappear with that much attenuation and it did not.I fixed the
connection and the BC junk is gone.
73 's  Dan K8RF   ex WT8N

--
FAQ on WWW:               http://www.contesting.com/topband.html
Submissions:              topband@contesting.com
Administrative requests:  topband-REQUEST@contesting.com
Sponsored by Akorn Access, Inc & KM9P