[RFI] AM Radio Interference On 75 meters

[Joe]

Ok, this is not my station.,.,the station (N6TNI) being affected is 8 miles, 
(approx) NE of the broadcast tower.

I came here as I am a member here and Dan is not.  There are a number of us 
trying to help him out with his problem, and I thought I would put forth his 
problem here to try and find a solution.

Sorry for the unintentional mislead.

It affects me because he can't hear me over the RFI..even when I crank up 
the amp to legal limits..Only a few of the 'very'  local yokels can put out 
a signal strong enough to get over the interference, and I sure am not local 
to him...(There is this very tiny obstacle between he and I..called the 
Sierra Nevada mountain range!  LOL)

Joe - WA6RKN

----- Original Message ----- 
From: "Jim Brown" <jim at audiosystemsgroup.com>
Subject: Re: [RFI] AM Radio Interference On 75 meters


> On 9/18/2012 9:54 AM, David Robbins wrote:
>> 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...
>
> Yes.   I did some poking on the FCC website.  KFBK is 50kW DA2 -- that is, 
> directional both day and night, different patterns day and night. The 
> nighttime pattern has deep nulls east and west, putting all of California 
> in their main lobes. WA6RKN is in Reno, which is 80-100 miles almost due 
> east of the KFBK transmitter site (which is 32 miles N of Sacramento).  If 
> their antenna system is functioning properly, there should not be much 
> fundamental in the direction of Reno at night.  Obviously that directivity 
> exists only on 1530, not on the frequencies of harmonics or spurs.