RadioBanter - View Single Post - ICOM AH-4 into Hy-Gain 64 foot Aluminum Mast

Jim Lux · April 29th 10, 07:03 PM posted to rec.radio.amateur.antenna

wrote:
On Apr 16, 6:16 pm, Jim Lux wrote:

But just feeding the end of a 1/2 wave wire sticking in the air is
asking for difficulties. Your coax is nominally 50 ohm sort of
impedance, and you'd be end feeding a dipole at a high Z point (a
thousand ohms, maybe).

Feeding it would be fairly easy.. But.. Just because it's a half
wave will not mean that there will be low ground losses if
ground mounted.
You would see less ground loss than a ground mount quarter
wave, but it could still be an issue. Note that most broadcasters
who run half waves, also use a set of half wave radials.
I'd probably rather use 32 ft masts supporting self supporting
32 ft radiators, and use a few sloping radials as radials, and
also to double as guy wires.
That will work fairly well with as few as three radials. More
to be optimum, but this is field day.. :/

And would strongly resemble the radiators at WWV...

If you do this, you'd put the AH4 at the join point too. For FD, you
might want to have the bottom 8-10 feet of the guy/radial be an
insulator, so that nobody touches the HV part of the antenna.