[TowerTalk] Who makes the best Quad design software

[n4kg@juno.com]

On Wed, 26 Jul 2000  Jack <poster@gate.net> writes:
> 
> Looking to make 6El Quad for 5Bands 10 thru 20
> 

You realize that the 10M spacing will be twice the electrical
spacing of the 20M elements assuming 5 elements per spreader.

Typically, the spacing is optimized for 10M and the designer
just lives with the closer spacing on the lower frequencies.

The Yagi Antenna Book by W2PV shows us that gain is primarily
a function of boom length and NOT the number of elements.  Between
.4 and .8 wavelengths, gain is almost identical for 4, 5, and 6 elements
for the same boomlength.

Several years ago, there was an article in Ham Radio Magazine 
comparing large quads and Yagi's.  The gain data was referenced
to a HyGain TH2 which was taken to each location on a trailer
mounted crankup tower.  The Quads did not compare well vs.
long boom Yagi's.  

It would be interesting to understand the interactions of multiple
quad directors for several bands.  I know that when Yagi's for
different bands are interlaced on the same boom that the low
frequency directors act as inefficient reflectors in front of the
higher frequency elements causing destructive interference
on the higher bands.  One must wonder about the effect of
a 20M Quad director on the higher frequency performance.

Reflectors line up without such destructive interference.  The
2L Force 12 C3, C3S, and 2L Quad are good examples which
successfully utilize this principle.

GL finding suitable software!

de  Tom  N4KG

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