On Tue, 9 Dec 2008 23:11:10 +0100, "Fred PA0FVH"
wrote:

Dear group,

As a temporarily solution I would like to use a cheap 5/8, 6/8 or 7/8 WL
commercially available CB antenna as a non resonant vertical with elevated
radials for use on 10 - 40 meters tuned by an automatic remote ATU at the
base of the antenna. I used MMANA and EZNEC (demo) to calculate the expected
impedance for the frequency range and found too many results for the height
of the antenna. Now I am confused about what to select.
Is 5/8WL on 10meters a good height or 8 meter (22')?
What I want is a low take off angle on 20 and 30 meters with high efficiency
and an impedance which my remote ATU can handle.

Hi Fred,

6/8th and 7/8th wavelength at 10M would not have the best low angle
charateristic. At the longer wavelengths it should get progressively
better (as you may tell from EZNEC demo).

7/8th wavelength at 10M may also be hard to match with your ATU, but
worth a try.

Shorter antennas for longer wavelengths may find more loss in the ATU
than you would care to have, but a 5/8ths at 10M might be the best
work-around; and the shortest you should go.

73's
Richard Clark, KB7QHC