[RFI] 9Khz spacing of intermodes carriers interference

[N1BUG]

On 01/20/2013 02:20 PM, Jim Brown wrote:
> I continue to be amazed that new members don't seem to study the long
> history of a reflector like this one before posting questions. The noise
> source is clearly some electronic device with a clock (because it
> repeats at 9kHz intervals), is being radiated by wires (cables)
> connected to that noise source, and picked up on antennas connected to
> the receiver.  The noise source could be the clock in a
> microprocessor-based products (almost any modern product), or it could
> be a switching power supply for anything from a battery charger to a
> wall wart to low voltage lighting to a doorbell.

Are you sure, Jim? He said he has carriers every 9 kHz. This is a 
well known problem from AM BC mixes in Europe, where their MW BC 
stations are spaced 9 kHz apart. I may be wrong but I believe the 9 
kHz spacing is used in the middle east also. What he is experiencing 
may be the same issue many us in North America have on 1810, 20, 30, 
40, ... due to mixes or harmonics from our MW BC stations spaced 10 kHz.

If that's the case I would look at ALL connections is ALL antenna 
systems, towers, masts, and any other metal (fences, roofing, etc.) 
within at least a few hundred feet of the antennas. I have found 
such issues contributing to the problem here.

73
-- 
Paul Kelley, N1BUG
RFI Committee chair,
Piscataquis Amateur Radio Club
http://www.k1pq.org