[TowerTalk] tribander/monobander stacking

[Pete Smith]

One of the problems with stacking tribanders is that the compromise spacing
is usually too close for 20 meters and way too far for 10.

I have a 2-high stack of C-3Es 28 feet apart, and have been toying with the
idea of adding a third yagi for 10 meters between them.  I thought I would
replicate the C-3E's 3-element 10-meter section, except for the open sleeve
feed system.  Modeling indicates really good performance enhancement with a
simple dipole driven element placed at ther average of the positions of the
C-3's 10-meter drivers, but that is with the feedpoints forced to be
completely in phase.  I'm wondering about the phase effect of a simple
gamma match vs the C-3's feed system, and about how to know the answer
short of building and trying, because I suspect that EZNEC could lead you
astray in trying to answer such questions...

Would it be feasible to keep the two C-3 drivers for this band, and feed
the longer of the two directly with coax, or will the absence of the 15 and
20-meter drivers mean that the feedpoint impedance will be too low for a
good match.  Would a hairpin match introduce less phase difference?

73, Pete Smith N4ZR

Contesting is ... Extreme Radio

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