In message <[EMAIL PROTECTED]>, Ullrich von
Bassewitz <[EMAIL PROTECTED]> writes
Surely this doesn't matter. Once the ATU in the K2 has been tuned once,
then it won't attempt to correct for any mismatch (caused by tuning the
mag loop) until you press the tune button again.
Trev G3ZYY
Unfortunately, it's not that easy. Matching a combined feeder/antenna system
with a tuner so that the PA sees 50 ohms doesn't mean that the antenna is
actually working. What you say is true, provided that the antenna is resonant,
and has 50 ohms with no imaginary part. But if you don't know that for sure,
for example if you're experimenting, or because the antenna has a very low
bandwidth (see below), just matching it with the ATU won't help.
A mag loop is special, because it has a very narrow bandwidth (often 10khz or
less), so changing frequency means retuning the antenna. But to tune the
antenna, one needs to know the real SWR. And this is the point where the ATU
needs to be switched off, because it will just correct the SWR as far as the
PA is concerned, but it will not make the antenna resonant.
Regards
Uz
--
Trevor Day
SIP: [EMAIL PROTECTED]
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