[NLRS] 1296 antenna

[Donn Baker]

Hi Mike,
Additional "reflectors," or a plane reflector can improve the F/B ratio of
a yagi... but experience doesn't show that its a really good idea.  Back
before numberical analysis was easy, yagis were optimized by trial and
error.  Using a plane reflector, or such could easily improve the F/B ratio
of a (by today's standards) mediocre design.  

A number of years ago, Cushcraft made a line of "trigonal" reflector
antennas.  Very distinctive-looking.  Performance was OK, but the extra
metal gave a couple of TENTHS of a dB gain and maybe 2-3 dB in F/B.

A good computer-aided design today can easily provide the same (or better!)
performance without the extral metal and windload.  (Most people I know
with the old CC 222 antenna have removed the Trigon, moved the remaining
reflector to the end of the boom, and gotten better perofrmance!  The
biggest selling point was that the Trigon said "Cushcraft" to everyone who
walked by !!

Yagi antennas are bound by realatively simple rules:  No matter what you
do, you have no choice but to trade gain for bandwidth for F/B ratio !  You
CANNOT "improve one without taking away from the other (or other TWO) !
Add in feed-point impedance, amount of metal, etc., and it really NEEDS
computer optimization!

73 Donn
WA2VOI/0

At 16:57 25-02-03 -0600, mike wrote:
>Hi, has anyone ever used or looked at the design of the DL6WU antennas 
>with the 8 reflectors on them?  Wimo sells them, but I was thinking of 
>making my own but I can't seem to find any information on the ones with 
>multiple reflectors.  I am tring to get good gain with a large f/b ratio.
>
>Any thoughts?
>
>Thanks
>Mike
>KB0ozn
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