Gregg wrote in message ...
Behold, Dale Parfitt signalled from keyed 4-1000A filament:

Antenna theory, and NEC modeling radically disagree with this- How
many
antennas do you want to see that are not 1/2 wave above a perfect
ground and yet show outstanding directionality?

W4OP

Phased arrays can be made directional. We are talking longwires here.

Not at 3 mhz. A 70 ft, or even a 100 ft wire is not even close to
qualifying as a longwire on 3mhz. It's just a random wire. Some of
the upper HF freq's, yes, it qualifies. On 3 mhz, it's not even a full
half wave. Worrying about the direction of the wire for 3 mhz use will
be a waste of time overall. It will be fairly omnidirectional and will
favor high angles. In fact, the maximum gain of such a wire on 3 mhz
will be straight up, unless he can get it real high up. You would have
to have the wire at least 120 ft in the air, to begin to lower the max
gain from 90 degrees overhead. The azumith pattern of the 100 ft wire
would be much like a normal dipole. A bit under 2 dbi gain in the
favored direction, and broadside to the wire like a dipole. Not a big
deal really. You will still hear plenty of signals off the ends. A
real longwire would show gain in line with the wire. "bidirectional".
Adding a terminating resister makes it fairly unidirectional. A
longwire must be at least 1 wave on the freq to be used. And thats a
real short longwire. Just barely is beginning to show gain off the
ends instead of broadside to the wire. Most are multi waves long on
the freq to be used. MK