3960khz is not a harmonic of 1530khz so something else is also happening here.
listen carefully to the kfbk signal and see if there is some other signal
mixing with it. check for other harmonics and other signals that it might be
mixing with to end up on 3960...
1530 + 2430khz?
1530*2 + 900khz?
1530*3 - 630khz?
1530 + 2*1215khz?
5490 - 1530khz?
etc, etc.
Then it must be mixing somewhere. add lots of attenuation, if the signal
suddenly dissappears its mixing in your radio... if not then its likely
outside, which you may have already confirmed by using other radios... assuming
they aren't overloaded the same way, you don't say how far away you are or how
strong the kfbk signal is at your location by itself. try driving around with
a well attenuated mobile radio and see if the signal gets stronger or weaker,
is it there a long distance from your home station? if so it is probalby not
being generated near your station. does it switch pattern or power from day to
night and does the signal appear/dissappear at the switch time? can other
hams hear it inside the normal ground wave distance for 3960khz? can anyone
get a bearing on it with a loop or beverages or 4-square?? can anyone hear it
farther away at night? lots of questions...
Sep 18, 2012 12:09:53 PM, wa6rkn@gmail.com wrote:
Here is the scenario. In the evening, through 6 am, radio station KFBK
Sacramento (1530 KHz) *blasts into 75 meters with a 25k wise signal at 3.960.
The signal is so stron, SSB conversations on 3.959 are impossible.
Notch and DSP filters in the radio do not work (Icom 757Pro) and other radios
set up at that location, either fixed or mobile, suffer the same issue.
Here is are 'RFI present', and 'RFI Absent' Videos to exhibit the problem.
Interference Present:
http://s1255.photobucket.com/albums/hh635/WA6RKN/?action=view¤t=RFIPresent.mp4
Interference absent:
http://s1255.photobucket.com/albums/hh635/WA6RKN/?action=view¤t=RFIAbsent.mp4
Any suggestions? Nothing has helped so far...line chokes, coils, Band pass
filters, etc.
Definitely a 3rd order harmonic..Radio station is blowing off the complaint, so
a formal complaint has been filed with the is so bad, we cannot communicate
with the involFCC, but that will umpteen years to get acted upon. (: It is so
bad, we cannot communicate with ham involved!
Thanks in advance for any help and suggestions.
Joe Wolfe
WA6RKN
_______________________________________________
RFI mailing list
RFI@contesting.com
http://lists.contesting.com/mailman/listinfo/rfi
_______________________________________________
RFI mailing list
RFI@contesting.com
http://lists.contesting.com/mailman/listinfo/rfi
|