[RFI] 9Khz spacing of intermodes carriers interference

[Cortland Richmond]

On 1/23/2013 1316, N1BUG wrote:
> ... 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.

That's why I suggested he look at intermod products. One of the stations 
I used was wrong, by the way, but he has identified his most aggressive 
neighboring stations.

I suggest trapping the strongest one *at the antenna*, in this case, the 
vertical, since changing the tuner settings there makes a difference. 
This could be as simple as IM in the SWR bridge diodes.

Cortland
KA5S