Jim VE3XJ wrote:
I can think of one - a horizontal half-wave radiator located one-
quater above ground, with a three wire reflector, as recommended by
our friends in Hawaii. The half-wave would be connected onto one
side of a quarter-wave balanced line shorted stub,
You are correct in concept, Jim. However, due to ground losses, in
order to be more efficient than a dipole at quarterwave height,
(efficiency is critical for utilization of the FT-817's QRP power
level) the zenith-oriented stacked dipole array you mention for NVIS
needs to have its lowest reflector or phased dipole element at least a
quarterwave above ground. However, you can achieve similar NVIS
gain antenna results simply by feeding two dipoles with equal
feedlines, with both of them about a quarterwave high, and separated
by at least 5/8wave spacing. Or easier yet, simply use a fullwave
horizontal loop at about a quarterwave height!
May I suggest that the excellent "NVIS" group on yahoogroups has
unlimited on-topic bandwidth to continue this exciting discussion. In
fact there is such a discussion going on there at his time we could
join in on. I look forward to engaging discourse on that forum, and
encourage other ops to meet there for a continuation.
IMHO, the FT-817 forum should be left to discussions of
FT-817-specific topics. The only thing that relates this very
interesting but diverging topic to FT-817 now is that the original
spark of the thread was an experiment that utilized FT-817 rigs as
transceivers.
Bonnie KQ6XA
