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Old RTTY 88mH inductors might be suitable if you
can find them.
or an automible ignition coil.
My approach is different. I prefer to
engineer/design the tx/pa for 50 ohms, feed this rf to the base of the anternna.
Resonate the antenna to the desired frequency with a suitable series inductor
then match this to the 50 ohm feed.
This way I can keep track of what is happening,
otherwise there are too many variables.
In the past on 137 and 500 kcs this has been my
approach and it has been sure fire every time. Get the antenna as high as
possible, throw out a few insulated ground radials, and a couple of earth rods,
nothing elaborate is required and you should be in business.
If I fire up on 9 kcs this will be my
method.
de mal/g3kev
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