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Old October 1st 05, 06:36 PM
Reg Edwards
 
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Hello Lee,

Thanks for letting me know that by giving your magloop half-a-chance
it performs according to expectations.

You have also demonstrated that the G5RV is not so hot as it is made
out to be by salesmen and they who have never tried anything else.

No disrespect intended to G5RV himself, now deceased, who claimed only
that it had a nice radiation pattern on 14.15 MHz which enabled him to
work both Europe and North America from South America without having
to climb ladders and change anything.

The magloop is by far the most efficient of all the antennas of
roughly the same physical size. Both theoretically and in practice. It
will do even better if you can get it well above ground in the
vertical plane.

In the horizontal plane it works best at the higher heights, above
surrounding obstructions like buildings. But in such surroundings
there is room to erect full-size dipoles anyway, which will obviously
do better still.

The main disadvantage on the 160 and 80 meter bands is the size,
physical and capacitance-wise, of the variable tuning capacitor. You
need a vaccuum capacitor of about 1000 pF max. By correct choice of
loop dimensions and minimum capacitor setting the 40 meter band can
also be covered. On 40 meters a small magloop can be highly
efficient. Investigate using program MAGLOOP4.

Are you using the small internal coupling loop, about 1/5 diameter of
main loop, to match to a 50-ohm feedline? This is the best and most
simple way to go,

A different ratio small loop diameter is needed for other feedline
impedances. The circuit behaves as if the turns ratio on a
transformer is being changed.

Let us know how your experiments proceed.
----
Reg, G4FGQ.