Ron wrote:
Ok I am getting confused. You are saying that a groundplane will not
work as good a a ground mounted vertical ? At what angle are you
talking about? Are you more interested in working 500 miles or 6,000
miles?

Ron

Nope. I think the elevated ground plane is superior to the
ground mount as long as it's high enough in the air to avoid
excess ground loss. As far as long haul, there may not be
too large a difference if each system is equal as far as ground
loss. IE: a ground mount with 120 radials, and a GP at 1/2 wave
high with 4 radials should show about the same efficiency. So
for long haul dx, they should be fairly close in theory. But...
You have a better ground/space wave with the elevated antenna.
This can come in handy when talking 50-100 miles away when
the band doesn't support NVIS with a dipole, etc..
When you run the elevated antenna, you must always think of
height in terms of wavelength, not feet or meters. A 2 meter GP
can be fairly low, and still very efficient. But not a low band GP.
A half wave is a different height on each band. Being I recommend
a minimum of 1/4 wave height when using only 4 radials, that
can be pretty high on a lower frequency. On 40m, I ran one at
36 ft at the base of the radiator. Thats just over 1/4 wave up.
If I ran the same antenna on 80m, I would have to mount it at
72 ft to have the same efficiency. About 145 ft on 160m.
Soooo...If you can't go that high, you must increase the number
of radials to lower the ground losses to a equal number.
If you have a ground mount with 120 radials, you need about 60 radials
if the antenna is at 1/8 wave. About 8-12 radials if the antenna is at
1/4 wave. About 3-4 radials if the antenna is at 1/2 wave. All these
have the same appx ground losses. So you can see, if you run a 80m
ground plane at 15 ft, the ground losses will be high unless you use
a whole lot of radials. So in that case, it's really more practical to
use the ground mount unless you don't mind all that wire in the air.
But equal loss ground mount vs ground plane? I'd take the ground
plane anyday... I ran one on 40m and it kicked serious butt on
long haul dx. And yes, I use the verticals on the low bands for
mostly long haul. I use dipoles, etc for NVIS.
MK