I am soliciting feedback and thoughts on a major problem I am having with an AM station causing me interference.
The station in question is approximately 6 miles (straight line) away from me and also, most of that straight line distance is over a salt water path. I never had a problem with this station, or any other AM radio station causing me interference, until January of this year.
In January, they were granted a construction permit to move from 30kw to 50kw. The problem manifests itself as carriers with audio all over HF and spaced 10, 20 or 30 KHz apart. Some of the carriers are S9, with clearly audible audio that is the same as that on the AM station. On some of the other carriers, I get some kind of mixing products and thus hear OTHER AM stations, such as WBZ (1030 KHz).
The interference lasted a few weeks in January, and then disappeared. It has resumed with a vengeance in the last week or so and seriously compromises my enjoyment of the hobby.
Some questions.
- How do I accurately characterize this problem? Is it front end overload? Or is this likely to be some kind of spurs from a poorly operating transmission system?
- Being 6 miles from this station, is it reasonable to expect this type of overload or interference?
- If this is not a reasonable expectation, would you go straight to the engineering staff of this station, or the FCC?
- Might my antennas be part of the problem? I have dipoles fed with 450 ohm open line, going to a 4:1 balun, and then a short run of coax. Would a different antenna possibly fix this?
Your thoughts and experiences with this type of problem are appreciated!
Edit: I tested with a 17m coax fed vertical and the interference is still there, which kind of eliminates my antenna system.
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