At 09:21 AM 9/10/2006, Daron J. Wilson wrote:
>In order to know the pattern of the FM antenna, you'll need to provide a
>good description, find the manufacturer and get some plots. Generally, they
>are stacked elements which provides the gain, but there are numerous
> > Now I don't know what an FM Stereo radiation pattern looks like, but
> > when I woke up this morning it occurred to me that if I had my
> > radio/antenna setup DIRECTLY below the FM setup, that I might have found
> > a null spot in the FM pattern? I think that if I can just clean up the
> > signal in this one antenna that we can live with the interference on the
> > rest of the gear.
And, while the mfr will probably have a good far field pattern, they
may not have a good nearfield pattern, and you may well be in the
near field. And, even if you are in a null, that might still be a
lot of power...
Say they're radiating 100W and you've got a 20dB null straight down
where you put your stuff. That's still like radiating a watt
straight at you, which might be enough to foul you up.
Most transmitting antennas have significant lumps and bumps in
directions other than desired one, and they'll be 15-20 dB down (or
more).. but, considering it from the antenna manufacturer's
viewpoint, they're not going to go to herculean efforts to turn a
20dB null into a 30dB null. The extra 0.9% efficiency probably isn't worth it.
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