On Tue, 23 Sep 2003 22:58:03 -0500, Cecil Moore
wrote:



In general, to use the variable ladder-line length approach that I use,
a dipole needs to be at least 1/2WL on the lowest frequency of operation.
For dipoles shorter than 1/2WL, as the dipole is made shorter, the resistance
goes down and the reactance goes up, causing the resistance at a current
maximum point to go lower and lower with increasing SWR.

Thanks, it just sounds like I need to make the antenna longer :-)

Bob
k5qwg

On 23 Sep 2003 13:59:49 GMT, ojunk (G. Doughty)
wrote:

I have a 10m dipole in the attic connected to my ic718. Is it possible to tune
it to 20m using the mfj 901b that I have? Does the dipole need to be 20m
length and then tuned down

Yes. Make the dipole twice as long, and then, with your tuner, you'll
be able to get a good swr from 20 meters through 10.

Bob
K5qwg

or can tuners tune to a resonance higher than that
of the existing dipole.

Cebik says a dipole needs to be at least 3/8 wavelength long on its
lowest frequency. I find 1/2 wavelength works a lot better.

I do not have a balun on it. On 10m I have an SWR of
1:1

Thanks
73
G. Doughty
KI4BBL