[Elecraft] EH Antenna Patent

[Tony Wells]

Hi John,

I don't personally have any bias one way or other on the efficacy on the EH,
as I've yet to build one myself. However being English, I have great
sympathy for the "underdog", enjoy taking part in long queues in shops,  and
frequently wear corduroy pants, smoke a pipe and wear a deerstalker hat :-)

But seriously. I don't think anyone has ever claimed EH has more gain than a
regular dipole. I believe the claims I've seen in print, is that a good EH,
mounted at the correct height *approaches* the gain of a well-erected dipole
whilst having a very small size compared with a full-size dipole.

This is a very important point, because how many people can erect a full
size 80M or 160M dipole in their backyard? Even a full size EH antenna for
136KHz can be built by obsessives in larger backyards. Personally I think it
is a waste of time to compare a 20M EH with a good 20M dipole. Moe
importantly, lets compare a 160M EH with a compromise 160M dipole. That
would be a more significant test.

There are two other claims in the patent which I think are very important to
test. Firstly on RX the antenna is supposed to be deaf to E-only radiation
and H-only radiation. Therefore the ant is supposed to have good immunity to
man-made electrical interference. Some testers have reported that fact.

The second claim is that by use of some kind of "dish" behind the antenna,
it will be possible to "focus", or at least sheild from directions other
than the intended path, the outgoing and incoming radiation. Again the
focussing/shielding of radiation in this way very problematic in most
backyards, particularly on 40, 80 and 160M. The implications of this type of
working are enourmous - including the possibility of EME HF transmission &
reception.

IMHO

Tony
M3CJF
G7IGG

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