Topband: My Turn For a Brain Pick - Sanity Check

[Charlie Cunningham]

I guess 90 degree phase shift might result in a cardioid pattern?

Charlie, K4OTV

-----Original Message-----
From: Topband [mailto:topband-bounces at contesting.com] On Behalf Of Tom W8JI
Sent: Wednesday, June 12, 2013 2:58 PM
To: topband
Subject: Re: Topband: My Turn For a Brain Pick - Sanity Check

> Christman phasing is at 71 degrees?  I was thinking 90 degree phasing.
> Whats the reasoning for this?


Optimum phasing of two verticals 1/4 wave apart is never 90 degrees, unless 
the user for some reason wants a single-point  zero-angle null and less than

maximum gain. Optimum element current delay for Ham use is always more than 
90 degrees, and generally around 110-120 degrees, with 1/4 wave spacing.

Making things more complex, phase shift in a delay line is never the line 
length unless the line is either 1/4 wave long or a multiple of 1/4 wave, or

the line has a reasonably well-matched termination.

With that in mind, a 71 degree long line might produce considerably 
different phase shift than the electrical line length, and the user probably

wants phase to be some other value than 90 degrees (if the user understands 
arrays and patterns).

73 Tom 

All good topband ops know how to put up a beverage at night.
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Topband Reflector