In article ,
John Smith wrote:

Roy Lewallen wrote:
I can add a little information that might be helpful.

When considering a receiving antenna, the single thing you need to be
concerned about is signal to noise ratio. Unless your antenna is
exceptionally poor and/or your receiver exceptionally noisy, making what
you receive louder is just a matter of turning up the volume, or adding
an audio amplifier if it's not loud enough. But it won't help you hear a
station, because it and the noise will get louder in the same proportion.


I differ; although, I can understand why Roy would reply in such a
simplistic manner ...

I agree with with Roy Lewallen. This is the only guy worth reading on
that amateur antenna news group.

If the antenna is resonate, matched to its' load, and is not using lossy
construction practices--a very magical thing occurs. And, in such a
situation, it appears as if a wire runs directly from the transmitter to
your antenna. Nicola Tesla first documents this, then others ...

However, most give up before they obtain the knowledge and construction
practices which produce such antennas--and, indeed, if you wish
broadband antennas, no matter how you construct them, they will only
produce this performance on a narrow band of frequencies, or perhaps,
just a single one ... but, they can be constructed to preform,
reasonably well, over a broadband of frequencies or even bands.

If you have immense focus, devotion to the construction of antennas, a
reasonably astute mind, and the necessary skills, a willingness to
construct until you have that "revelation"--the realization of all this
awaits you. :-)

Resonance is a wonderful thing but we talking about broadband antennas
so the only way to mitigate this is to have to tune the antenna as you
tune the radio. This can be done manually and remotely but is more work
than most people would want to do tuning up and down the band.

I'm not saying you are wrong, just that you bring up another parameter
of antennas or circuits in general that offer an improvement to signal
to noise.

There are two main ways to improve signal to noise. Solution one is
Roy's using antenna directional gain and nulls. This works because noise
that comes from every direction is limited. The signal is also increased
when it is in the part of the antenna pattern that has gain.

The Mr. Smith solution limits bandwidth. This works because noise is
broadband and so decreasing the bandwidth limits the noise. The signal
is also increased when the tuned antenna resonates at that frequency.

Two different parameters that in different ways improve signal to noise.

--
Telamon
Ventura, California