[Antennas] Re: [dx-list] Yagi height and DX

2002年4月13日 15:31:37 -0500

Jim, after re=reading Mark's posting, I wonder if what he stated is really
what he meant.
In any event, the improvement in gain is pretty marginal, and although the
decrease in the so-called "take-off angle" looks impressive, you have to
look at all aspects of the predicted pattern, not just that one aspect of
the elevation pattern.
The practical aspects, other than the cost, of going from 20 ft on the
tower to 40 ft could be substantial, since it could mean the difference
between a short tower supported by the house and the need for a fully guyed
structure or a much heavier self-supporting tower. There are also
consequences as to antenna access - climbing 40 ft is more daunting to some
than going up 20 ft.
But, on the other hand, that 40 ft tower could support some pretty good
wire antennas!
Trying not to nit pick, but there seems to be more here than just the cost
of two tower sections and the relatively small gain and pattern changes.
73/72/oo, George W5YR - the Yellow Rose of Texas 
Fairview, TX 30 mi NE of Dallas in Collin county EM13qe 
Amateur Radio W5YR, in the 56th year and it just keeps getting better!
QRP-L 1373 NETXQRP 6 SOC 262 COG 8 FPQRP 404 TEN-X 11771 I-LINK 11735
Icom IC-756PRO #02121 Kachina 505 DSP #91900556 Icom IC-765 #02437
James Nipper wrote:
>> Mark, with all due respect, I disagree with your conclusions !!! The
> extra gain noted (especially on 20M) , plus the improved take-off angle,
> although not **huge**, would still seem to be worth the very little extra
> expense of two tower sections !!
>> The real experts on this list can now chime in, but unless I am wrong, your
> data looks valid, but I don't quite understand your conclusions !!
>> Anyhow, good Dx to You !!