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Old August 21st 03, 02:45 PM
Mark Keith
 
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Richard Clark wrote in message

Use a tuner and forget tuning the radials. You might be tempted to
build them to "formula" but given that they will no doubt be of the
drooping variety, then that is an entirely different game. As such,
add as many as you are comfortable with, as long as you can make them
without having to bury their tips (a good idea is that their lowest
point should be out of reach).


Myself, I would tune them, or have them very close. Or at least on the
preferred band. Better decoupling from the feedline for one thing. If
the radials do not present a low Z for a certain band, they won't work
too well at all. I would grount mount if I didn't want to tune the
radials. It's going to be very hard to get proper performance on all
bands with only one tuning setup, unless maybe he uses an autotuner of
some type. "elevated"
I'd pick the most likely used bands and build for those. IE: it will
be hard to run 40 and 20 both, with good results on both bands. If I
ran 40/17m as the main design, I'd forget about 20m. And visa versa.
If not, be prepared for mediocre results on one of the bands. I've
never tried feeding an elevated GP/non resonant radials with ladder
line and a tuner. I know it can be done, but I wonder about the amount
of common mode currents and performance on "non radialed" bands,
compared to a normal setup with 1/4 wave radials.

Be aware that as impressive as it may feel, the height may be a
detriment in the higher HF (too long and radiation will be skyward,
bound).


Not the height, but the length of the antenna is too tall for the
higher HF bands for good low angle performance. IE: 10-12 meters. It
will be ok 15m down.
This is probably what you meant...
MK