Re: [TowerTalk] Stacking Distance for M2'd 6m7JHV?

[Bill Tippett <btippett@alum.mit.edu>]

W6RMK wrote:
> It might be interesting to trade that scheme (which has 4 possible
> settings) against a scheme where you combine the two antennas with
> 0,90,180, or 270 degrees phase shift between them, which also has 4
> settings.


W5WVO wrote:>But how to model the
effect of various phase shifts on take-off angle? Does anyone have a handle on
that? I don't know of any software that is set up to do the math involved in
this scenario. Any ideas or recommendations?

        HFTA will handle 0 and 180 degrees, but not 90 and 270.  From
what I recall when playing around with various phasing combinations using
Eznec, 0 and 180 are really the most useful cases anyway.  N6BV might
want to comment so I'm copying him on this.

                                                73,  Bill  W4ZV

 From page 16 of HFTA documentation:


Out-of-Phase Feed There is a useful new feature in HFTA that earlier 
versions (such as YT) didn't have. You may choose to use out-of-phase drive 
to individual antennas in a stack. You do this by appending an asterisk (*) 
to the end of a height number. For example, in a stack at 90, 60 and 30 
feet, you might run the top 90-foot high antenna out-of-phase with the two 
lower Yagis. Enter 90* in the top left text box. Although employing 
out-of-phase drive is not often useful in terms of increasing the overall 
performance of a stack of Yagis, sometimes it can cover high angles that a 
stack or any single antenna cannot accomplish because of a steep 
mountainous terrain.


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