Andy Ikin wrote:
"Taking an other look at amplifiers for the Pennant. I would suggest
using a Hi z input balanced J fet or mos fet amp directly at the antenna.
This would provide a good match to the antenna z and provide the 50 Ohm
feeder match. More importantly, this would improve the common mode
feeder/antenna isolation."
==========
This was previously suggested by Bruce, AA4Z in his e-mail on 28 June
2000. I thought his suggestion and K9AY's reply would be of interest.
Here are those messages:
Bruce, AA4Z asked:
"Has anyone found a source for Pennent/Flag/Beverage antenna preamps with
a high Z adjustable input and 50 ohm output eliminating the need for a
transformer?"
Gary, K9AY replied:
"The scheme you propose may prove unsatisfactory. The Pennant and Flag
antennas are independent of ground and must be isolated from the
feedline. A preamplifier will almost certainly have a common ground for
both input and output, and thus, no isolation of the "cold" side.
A transformer with separate primary and secondary windings is required,
or an autoformer style transformer plus a choke balun. I suppose you
could use a choke balun on the feedline side of a Hi-Z input preamp, but
you were trying to eliminate the transformer so it defeats your original
purpose."
==========
73, de Earl, K6SE
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