Loading Coils; was : Vincent antenna
Richard Clark wrote in
:
On Mon, 03 Dec 2007 23:23:45 GMT, Cecil Moore
wrote:
In words, with a 50 ohm source, set up an autotransformer to
deliver a signal to a 3600 ohm Z0 environment. Put the 75m Texas
I can't see why an attempt to impedance match the source was necessary,
the reflection coefficient is determined solely by the load and line
characteristics.
Bugcatcher coil in series with a 3600 ohm non-inductive load.
Measure the phase shift through the coil at 4 MHz. I eyeballed
it at ~25 degrees on a dual-trace 100 MHz O'scope.
If you were confident that reflection was insignificant, then this test
design might properly reveal the one way delay of the transmission line
section.
And what was it when you cut the coil in half?
Sampling the forward wave (which should be the dominant wave if with an
approximatly matched load) at various points and comparing phase (wrt
source) with displacement might establish if the apparent phase velocity
is constant.
I don't suspect that the outcome of a properly designed and executed
experiment is going to surprise anyone.
Interesting as the answer is, the question still remains, what can one do
with the knowledge of the one way delay of a short loading coil when
designing a loaded monopole?
Owen
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