Resonant antennas are easier to feed, but not necessarily a great deal
more efficient radiators than short dipoles. I've used wires as short as
80' center fed for 160M and 80M. And worked the paths I wanted to work.
Sure the antenna tuner was picky and needed changes often when I change
frequency.
Antenna radiation comes from current through a length of conductor. The
ends add little to radiation because the current is small, they just
make resonating easier. But an eighth wave of radiator terminated with a
series resonant loading coil and capacity hat radiates pretty good. When
its shortened to make a mobile antenna it still radiates far better than
a dummy load.
The important thing about a short antenna is that it radiates a whole
lot better than the full half wave antenna (stored in the closet) that
can't be put up because the lot is too small. The short wire isn't
optimum, it isn't convenient for tuning, but it can be tuned and it will
get out.
73, Jerry, K0CQ
--
Entire content copyright Dr. Gerald N. Johnson, electrical engineer.
Reproduction by permission only.
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