On Sunday, October 4, 2015 at 9:05:23 AM UTC-5, John S wrote:
How less efficient is a short vertical than a 1/4 vertical?

I would like to see some numbers. It is a ground plane with 4 radials
(typical). Free space.

Assume a source at the base. The type of source is your choice. EZNEC
defaults to one amp, but can be changed to a constant power of your choice.

I'm sure I've left out additional requirements, but maybe this will be
a healthy discussion even so. Suggestions are welcome.

One could spit out numbers for days given all the possibilities.
Too vague are the specs.. IE: you state four radials, but model in
free space. So would ground losses be an issue or not? Also the height
above ground in wavelength makes a large difference. Four radials at 1/2
wave up provide low ground losses, but four radials at 1/10 wave up are
not so hot. Much higher ground losses.

Being as all short radiators radiate nearly all power fed to them, barring
any small resistive losses, the only thing left are the matching losses.

And for playing "what if", a program like "vertload" could be used for
getting an idea of the efficiency of the various length radiators and
spit out the number of turns needed, etc.. Will give the efficiency using
whatever ground number you punch in as I recall.
That's what I used to use when building mobile whips. I think it also
lets you adjust the whip both below and above the coil. So you can vary
the location of the coil.

The only problem with vertload is it's old and DOS I think, so newer OS's
won't run it without a DOS BOX or whatever.. XP will run em as is..
So I can still use them on my old laptop. This box is Win7 64, and it won't
run em without the DOS program, which I haven't bothered with yet.
But they say it will work.. I forgot the exact name of the DOS emulator,
would I'm sure google knows what and where it is.