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Expected range increase from 6db vs. 3db vhf antenna
In article ,
(Sailman) wrote:
So how should I think about translating "2x the power" into a rough
estimate of increased distance?
You really can't. Once you hit the Radio Horizon for your antenna
height, any increase in power is just going out over the heads of your
intended listeners. By increasing the power, you will cause your signal
to noise ratio to improve at the Radio Horizon, but you really don't
extend that horizon by increasing the power, or the antenna gain.
The exceptions to the preceeding rule are, that Vhf Signals can, and do,
DUCT in Thermal Inversion Layers, that are common in some places. These
ducts can cause Vhf signals to be heard and communicated on, many
hudreds of miles further than the Radio Horizon. They do, however,
change and disappear quite often, with weather fronts, and shouldn't be
reallied on for communications.
I pioneered a bunch of these Vhf/Uhf Paths in Brystol Bay, Alaska,
for the Salmon Industry, back in the late 70's, that are still in
use today. When a Low Pressure Front moves thru the area, these Radio
Paths go Stoned Dead for a few days untill the thermal Inversion
rebuilds. Path Studies that we did back then, showed that these things
were good for 60 to 70 days out of the 90 day Salmon Season, and that
justifdied using them, untill good phone service was established in the
region. Now they are just a cheap backup for commercial communications.
Bruce in alaska Who gives Bill Forgey, K7KDU all the credit for
coming up with the idea, in the first place....
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add a 2 before @
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