I’m thinking of building a 3-stack of tribanders. Folks who are familiar
with stacked monobanders give me doubtful looks. I’m wondering who on the
list has actual experience stacking tribanders, and what practical
observations they can offer.
By way of background, I was an EE in a past life, with a bit of professional
experience with phased arrays for VHF/UHF and shortwave broadcast, and
radar. So I appreciate the phased array concept.
My contemplated stack has 8.6m spacing between antennas (with the top
antenna at 130’). I recognize that half wave spacing has certain desirable
attributes, and that my spacing is a bit large for 15m and a bit short for
20m. But modeling suggests that’s not a big deal. (I may cover 10m
separately.)
I expect to turn the top two antennas in tandem, and have the bottom antenna
independently rotatable.
I recognize that tribanders are, themselves, compromises. However, current
designs seem a vast improvement over the designs of 30 years ago. (I’m
thinking of using one of the interlaced models, e.g., with 2 or 3 full sized
elements per band.)
I’m not interested in longer boom yagis – narrow in azimuth and broad in
elevation pattern (e.g., beaming Europe only to put a null on Africa, or
beaming Japan only to put a null on NZ/Australia). I’d rather have a
broader azimuthal pattern, and a selection of different elevation patterns –
depending on whether I drive antennas #1+#2+#3, or #1+#2, or # 2+#3, or
#1+#3, or #1, or # 2 or# 3.
What issues/observations can folks with experience relate?
Tnx/73,
Bill, K2PO/7
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