> What's an FOM?
Figure of merit.
> And, for us non-engineers, bottom line, can we still
safely say more
> efficient antennas with more gain are going to tend to be
better, in
> general, than less efficient antennas with less gain?
For transmitting. Not for receiving.
> Realizing that, though it seems intuitive that more
efficient is ALWAYS
> better than less efficient, that there are exceptions,
such as low noise
> receiving antennas that may be less efficient.
That's right. When receiving, antenna system gain doesn't
matter until the system's internal noise starts to affect
S/N ratio. Normally external noise limits S/N. It's all a
response issue caused by pattern (which includes
polarization effects) and directions.
> Resulting in the conclusion we often hear, "You can't have
too many
> antennas," meaning it's nice to be able to switch to
different antennas to
> find the best one in the circumstance.
That's right too, and the best S/N may not be on the one
that has the best signal level.
That's why we can't assign a FOM to receiving based solely
on antenna gain.
73 Tom
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