[TowerTalk] antenna choices

[Jim Brown]

On Tue,4/7/2015 1:06 PM, Joe Subich, W4TV wrote:
> Worth noting when evaluating the N2IC report is that the C31XR has an
> effective boom length of 25 feet on 20 meters, 22 feet on 15 meters,
> and 25 feet on 10 meters.  The C31XR compares favorably with, but lags
> the N6BV "optimized" Hy-Gain antennas in the Antenna Book by .5 dB on
> 20, 1.2 dB on 15 and .6 to 1.2 dB on 10.  Dean's design goals with the
> Antenna Book examples were balanced gain and front to back with
> acceptable SWR across the band.  Those examples are not "maximum
> gain" designs.

Yes. BUT -- few of us would be happy with a design that wasn't 
reasonably well balanced, at least for forward gain over the band and 
SWR bandwidth. The ARRL Antenna Book does a good job of showing that, 
with graphs of gain, SWR, and F/B all plotted vs frequency for designs 
optimized for each of those parameters and for a balance between all 
three. For the few Yagis I've designed, I've tried to optimize for gain 
and reasonable VSWR over the desired frequency range, sacrificing F/B if 
needed.

In his very useful book, "Array of Light," N6BT also makes a point of 
making designs reasonably insensitive to variables that are difficult to 
control, like mounting height and close building tolerances.

73, Jim K9YC