"Dale Parfitt" wrote
Visit Reg Edward's site to see how to electrically shorten a radiator with
inductive loading.

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Hi Dale, yo took the words right out of mar mouf.

Program HELICAL deals with a vertical, continuously-loaded, plastic-pipe
antenna, above a ground or above the roof of a vehicle. Because of the
uncertain surroundings the program will put you in the right ball park with
the number of turns on a pipe of given length and diameter. Putting two
antennas back-to-back allows the design of short dipoles without any ground
loss.

Program MIDLOAD deals directly with short, centre-fed, continuously-loaded
1/2-wave dipoles with a variety of feeding arrangements. May be either
vertical or horizontal dipoles versus height above ground.

These antenna programs are most suitable for the 160, 80 meter and perhaps
40m bands where space is at a premium. At the higher frequencies
lump-loading coils can be (or must be) used.

The advantage of continuous helical windings is that THICK, spaced, wire
(copper pipe even) can be used. Thick wire means low loss resistance and
higher radiating efficiency. Otherwise there's no point in using long
helical windings.

There are a variety of my programs which use lumped loading coils some of
which incorporate coil design and feedpoint impedance-matching arrangements.
In the website refer to the one-line descriptions following each clickable
program name.

Incidentally, changing the subject, the reason for using single-turn coils
for magloops is that it allows a VERY thick conductor, a 1" or 2" copper
pipe, to be used. Otherwise there's no point in using a magloop for
transmitting purposes. The magloop is by far most efficient of all the small
(in terms of wavelength) antennas. The disadvantage is its expensive or
heavily-engineered tuning capacitor. Use program MAGLOOP4 for an accurate
performance analysis.

For all readers, download the small, single-file, easy to use, programs in a
few seconds from the following website and run immediately. Get your money
back if dissatisfied!
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Regards from Reg, G4FGQ
For Free Radio Design Software go to
http://www.btinternet.com/~g4fgq.regp
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