> Jim Lux wrote:
> At 02:56 PM 3/13/2006, doc wrote:
>> Is it fair to generalize that proximate objects
>> will almost always detune an antenna to a higher
>> frequency?
>
> No...
>
> imagine putting a giant sheet of metal near a dipole. It will tend to
> reduce the resonant frequency because it increases the apparent
> capacitance.
>
> Or, for the example originally given (a dipole close to the ground), the
> ground lowers the resonant frequency. So, when you raise it, the
> resonant frequency goes up.
Sorry, was distracted by a 3yr old ... not to say
that my attention span is any better at times!
I should have asked if proximity to solid objects
typically lowers the frequency of resonance and
increasing distance thus increases the frequency
of resonance and I gather that the answer is generally
yes.
This means that antennas on a tiltover will want to
be tuned a little low when nearer the ground so when
they are lifted they will be close to the desired
resonance.
The van misbehaved today so I could not recover
my tiltover section from the welding shop and do
some direct experiments ... soon and very soon!
--
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Thanks! & 73, doc kd4e
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KD4E =====================================
West Central Florida
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