Paul,
I plan to use an inductive coupled primary coil, out of bigger wire. The
impedance level is still not defined. Maybe it will not be 50 Ohm, Just
anything above some Ohms. The PA has a big output transformer with different
numbers of turns, like a universal transformer. So i will see which tap is the
best. The output power can simply be varied by this way. Using a parallel C to
the primary coil might be an idea. But the antenna system has a high Z and i
will watch the voltage form in a first step, so no problem. Or do you think i
MUST have to built a simple band pass? Hm, that could be done with a audio
diplexer.... I will see...
It would be nice if others than Markus and me would also start to try such an
antenna! Walter/DJ2LF? But i understand, that you want to wait until the 100m
antenna has produced some records ;-)
This weekend, i have no time, i am sorry! As you know i have changed my qth
from Darmstadt to Heidelberg and have found new friends here who want to do
something here with me. And i already have told them last week that i have to
build a TX coil on a water barrel, hi. But my job is a nice one: Each friday
and monday i have free time, so my weekend is 4 days! That means that we can do
tests even on friday to monday, just when wind and fun is available :-)
73, Stefan/DK7FC
________________________________
Von: [email protected] im Auftrag von Paul Nicholson
Gesendet: Di 09.03.2010 18:47
An: [email protected]
Betreff: Re: LF: Possible VLF HV problems, or not?
I agree with Alexander, 10kV is not so high. If you were looking
at > 30kV or 40kV or so, then it might become an issue. But even
then it can be controlled at the ends.
I think it just has to be tried and the practical limits found.
It is good to consider these things as the territory is unfamiliar.
Stefan, how will you feed power into the coil? I am running some
circuit models to see the effect of harmonics and coil overtones.
I want to see how much radiation there is when a drive harmonic
hits a coil overtone, as will happen by chance. Will you drive a
square wave into the base from a switching amp? No the voltage
needed will be too high - perhaps you are using a primary coil
or transformer?
--
Paul Nicholson
--
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