On 3/26/02 2:34 PM, "Marty Tippin" <nw0l@yahoo.com> wrote:
> Whose gain figures do you use? The manufacturer's or something that more
> closely represents reality?
Anyone using the manufacturers' claims are just disadvantaging themselves,
HI HI. Especially the ones using 11m antennas on 10m :-P.
It has been shown quite often (see past issues of Communications Quarterly)
that gain of a Yagi-Uda can be pretty well predicted by the boom length.
You can completely ignore the number of elements and come within a dB or
so.
(OK, so the Super-Gain (Uzkov limit) antennas will have a tad of advantage,
but there are not many of those antennas.)
Gain of horizontally polarized HF antennas versus height is also pretty
well establish (there is a slight additional ground gain for a multi-element
Yagi-Uda compared to a dipole, but again it is not that great).
Or, a simple table could be created (dB vs boom length and height). Same
thing with applying a gain factor to stacks (at least we know what the
ultimate maximum is :-).
Wire antennas (dipoles, EDZ, Vee, Rhombics) can be categorized by
wavelengths.
And we know what the maximum gain of a vertical is :-). If you don't
live in the middle of the ocean or a salt marsh, too bad :-).
Just use best case EIRP. That way, contesters will really go optimize
their station, feedlines and antenna losses (like burnt plastic traps :-)
...and flood their county with salt water.
The CQWW "tribander plus wire" is basically an EIRP equalizer within
a couple of dB, except for the factor in antenna height.
73
Chen, AA6TY
|