David Woolley wrote:
The requirement that I'm trying to meet is that the K2 chassis not be RF
hot and that, if I connect the mains ground, there is no significant RF
in that ground. RF choking the ground has the same problem that the
choke impedance will not be large compared with an off resonant antenna.
That requires driving an antenna that is, at least approximately,
balanced - in reality it's not possible for me to get true balance,
because the antenna has to be indoors.
The usual solutions to RF on the chassis are 1) changing the feedline
length (so that it is not close to an odd multiple of a quarter
wavelength) and 2) connecting a quarter wavelength radial to the chassis
to decouple it. Of course these solutions can be more complicated in
multiband situations.
In other words, you added a balanced tuner on the antenna side of the
balun! I'll accept that there may be solutions that do coarse tuning on
the antenna side, to get the impedance into the right ball park, then
use the unbalanced tuner, on the equipment side, to do the fine tuning,
but what you are describing is still doing a lot of the tuning antenna
side.
OK, I'll accept that. I wasn't trying to prove a point about where the
tuning takes place, but rather to suggest that reactance has a lot to do
with balun efficiency and that the place to start when trying to match
an antenna is by measuring the r and x so you know what the problem is.
--
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco
_______________________________________________
Elecraft mailing list
Post to: Elecraft@mailman.qth.net
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com
