[TowerTalk] 80 M 4 SQUARE MODELING

StellarCAT rxdesign at ssvecnet.com
Sat Jul 22 13:39:14 EDT 2017

Excellent point! Indeed they assume there's proper current distribution - 
and John's book seems to imply if not outright state there will NOT be 
proper current distribution under the best of circumstances...

but once again the bottom line is this: if its your only choice consider 
trying it.


-----Original Message----- 
From: Gary Johnson
Sent: Saturday, July 22, 2017 12:33 PM
To: towertalk at contesting.com
Subject: Re: [TowerTalk] 80 M 4 SQUARE MODELING

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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