JB wrote:

...
Actually there is no reason TO have a resonant length antenna if you can
tune it electrically. After all, you may want to tune around some. I can
tell you it is a pain to have to go out and physically make adjustments for
any frequency excursion. There are many nonresonant length antennas that
outperform the resonant length. The 5/8 wave vertical comes to mind. A
long-wire provides a larger capture area. Then there are phased arrays that
reinforce. Look up the HAARP project and see how they made a very large
array and were able to electrically steer the pattern. Cool!

The more you know, the cheaper it gets, and the more you giggle when it
works. The only problem is you get hooked and want to do so much more.


Well, examine a mechanical tuning fork. They are cut to an exact
physical length for resonance, the are very sharp tuning. Now, it would
be possible to "lengthen" such a tuning fork with some coil of material,
or portion of a turn of material. There is a reason for this; as,
although it could be done, it would not be as efficient as one cut to
the exact length; plus, you would induce a high probability of increased
harmonics as a freq(s) which the fork was not created to induce ...
there are exact equivalents in the electrical world of RF ...

As you point out, physical length resonance is NOT a requirement ... it
is simply "best" ...

Regards,
JS