> > Measured on their range-they used to be based in Cleveland, and my
> > father was one of the designers.
> > (anybody here remember the PRO-27JR 27Mhz antenna? Or the
> original 4BTV?)
> > --
> > Jim Barbour
> > WD8CHL
> >
>
> With all due respect to your father Jim, I think that 4 db of gain is
> wishful thinking. A 5/8 wave length antenna theoretically is
> a little over 3
> db and in real life 3 db is seldom realized. If I am not
> mistaken a .64
> wavelength would have at most a tenth of a db advantage over
> a 5/8 antenna.
>
> 73
> Gary K4FMX
There are a lot of unknown variables here, including, but not limited to the
size of the ground plane the antennas were mounted on, their heights above
the ground plane, the method of coupling to the ground plane (direct, mag
mount, etc.), matching networks' efficiencies, etc.. And more importantly,
was the 4 dB gain a peak value, or at 0 degrees elevation?
Typically a 5/8 wave over a perfect ground plane should be a little more
than 3 dB better than a 1/4 wave on the horizon, but with so many unknowns
and so much variability in mobile installations, there doesn't seem to be a
definitive conclusion to be drawn here. Maybe Jim can provide more detail.
--- Jeff
