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Old April 29th 06, 03:46 AM posted to rec.radio.amateur.antenna
Buck
 
Posts: n/a
Default TT-247 and 102 whip for mobile antenna ?

On 28 Apr 2006 08:29:58 -0700, "
wrote:

If there is a heating problem with a short dipole, there will be a
heating problem with a 102" whip.

Some automatic tuners may do OK with the short whip. I think SGC does
this, but if it works and is reasonably low-loss it is because the
tuner is designed to do well with a short whip.

One way to make the tuner match a short whip better on low frequencies
is to include a loading coil, in this case, at the base, to bring the
antenna into resonance. The impedance of the antenna will then be a low
resistive impedance, rather than a low resistive part and lots of
capacitative reactance. The tuner will handle this better than the
very short whip without a coil.

It seems to me that a short-whip automatic tuner should have an
inductance in series with the antenna input, maybe a LCL tee network.
I don't know what sort of topology the T-T 247 has but I don't think
anyone is building an LCL tee manual antenna tuner. It'd be easy to do
in an auto tuner though.

Anyone know the internals of the SGC short whip tuner (the one with the
whip mounted to it)?

Dan,
N3OX


I believe my tuner is CLC, it has two caps and the inductor.


--
73 for now
Buck
N4PGW