Concerning vertical stacking of OWA or other Yagi - there is no practical
worth mentioning difference on HF.
There is a significant difference while stacking various LONG VHF Yagis for
EME or Contesting purposes, but it is different more complicated case very
nicely studied on the both SM.... www.
I do believe I have came with some answers to all your questions. What I
wanted to say is that in some sort of propagation the antennas are too close
and you are getting nothing, in other you might win a lot, but as I do
believe you do not loose concerning signal in the air.
What you lose in any case is time, aluminium, cables... MONEY etc...., but
it is a different story, better not to count because if you start the only
thing which you can find is that you are completely crazy idiot. NOTHING
OK let's make more antennas !
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