If those bands on the old antenna were already resonant, and they
matched, then you didn't need 450 Ohm ladder line.

If you are going to use 450 Ohm ladder line on a generic doublet, it
stands to reason you won't be resonant much anywhere (or you don't
count on it) and you anticipate tuning and use this line for low loss.

Thanks, Richard.

My main concern was that trying to tune a 100 foot dipole on 75M
might cause problems due to the dipole being shorter than halfwave on
75M. From what I am now concluding from your comments, and others',
this probably won't be an issue?


Ed

On Mon, 17 Oct 2005 02:48:13 GMT, Ed
wrote:

My main concern was that trying to tune a 100 foot dipole on 75M
might cause problems due to the dipole being shorter than halfwave on
75M. From what I am now concluding from your comments, and others',
this probably won't be an issue?

Hi Ed,

An antenna can be too long, an antenna can be too short. Somewhere
over the span of all the HF bands, one antenna qualifies for one of
those two conditions. The issue is can you cope?

A tuner can usually resolve the problem of match, but it cannot do
anything about line loss for certain situations. Using the ladder
line answers that.

Finally, unless you demand the point shaving of eking out every tenth
dB for contesting, the combination of a 100 foot doublet, a tuner and
ladder line will give you just as good service as a tuned dipole.

73's
Richard Clark, KB7QHC

Ed wrote:
My main concern was that trying to tune a 100 foot dipole on 75M
might cause problems due to the dipole being shorter than halfwave on
75M. From what I am now concluding from your comments, and others',
this probably won't be an issue?

Walter Maxwell of "Reflections" fame recommends a minimum length
for a dipole of 3/8 wavelength. 102 ft is 3/8 wavelength on
about 3.6 MHz so it should and does work well. That's the length
of my dipole.
--
73, Cecil http://www.qsl.net/w5dxp