K4SAV wrote:
> When the feedline appears as part of the antenna, it will change the
> resonant frequency of the antenna. Try feeding an off center fed
> dipole without a choke balun and see what the feedline does to the
> resonant frequency of the antenna.
Well, of course the resonant frequency will change if the feedline is
part of the antenna, but under those circumstances, you are no longer
discussing the original antenna. This is the old trick to short the
PL259 in the shack, and connect it to one side of the balun of a tuner.
In such a manner, a 80 meter dipole can be used on 160 meters.
And, it's obvious that we have different opinions, so let me try one
more time. Nowhere in the formula for a resonant antenna does "feed line
" length appear. As for the case cited above, the resonate frequency of
the original antenna does not change, however, reactance is introduced
which may cause an "apparent" change. But, if you introduced an
equivilent amount of opposite reactance at the feed point, you will find
the resonant frequency is identical.
I was under he impression we were discussing a 1/4 wave inverted L fed
with coax.
And of course, if you do not use a choke balun, the feedline will
radiate, and that radiation will show in both the pattern and the
"apparent resonance" of the antenna.
73
Ed
And you will also find in almost any antenna handbook a statement that
" until the number of radials approaches a certain point, their length
has little to do with the performance of the antenna". And in fact, the
recommended proceedure if you have less than optimum space is that "more
short radials are more effective than 1 or 2 long ones".
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