One more thing that almost nobody pays attention to is the fact that the Comtek
and DXE phasing boxes are optimized for one and only one specific array
configuration: fat, full-sized verticals over a very substantial ground plane,
and with no other interacting objects. They are NOT magic boxes that guarantee
an ideal pattern under all circumstances; feedpoint impedance is key. Carefully
study Low Band DXing. It is feasible to optimize pattern (especially F/B) for
any reasonable set of verticals, but only if you do the detailed impedance
measurements in the field, followed by the calculations, and finally some
modifications to the phasing network. To verify everything, you can insert
current transformers at the feedpoints and measure magnitude and phase, then
tweak as necessary. I just went thru all this with a vertical array for 40m,
and it was a real eye-opener.
Gary NA6O
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