It's fairly well known, I think, that certain "magic" stacking distances
yield particularly good results, like 50/100 ft. for 20m. yagis, for
example. But one of the frustrations of stacking tribanders is the need to
choose a compromise spacing -- one that probably is not optimum on any
particular band. 28-32 feet seems to be commonly used in this case for a
2-high stack.
I'm wondering if anyone has ever tried a 3-high tribander stack with the 3
bays spaced differently from one another -- for example, at 25, 50 and 100
ft. above ground -- in an effort to produce better pattern on more bands?
By "tried", I mean modeled or real life. I'm happy to spend some time
iterating this problem, but I don't have AO, so it would be helpful to have
some ideas of what *doesn't* work before I start.
In a similar vein, loss of F/B ratio in a stack (as compared with a single
yagi) is a well-known phenomenon. It seems logical that a yagi that has
good F/B alone might not be optimally set up for F/B when used in a stack.
Are there any general rules of thumb for how yagis tend to "need" to be
adjusted when placed in 2 or 3-high stacks?
A final question -- is anyone aware of any effort afoot to bring K6STI's
software back to market, under the same or different ownership? When I get
into things like this I really wish EZNEC had an optimizer!
73, Pete Smith N4ZR
n4zr@contesting.com
Sometimes a tower is just a tower
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