[TowerTalk] 2 wire Beverage query

[i4jmy@iol.it]

> ---------- Initial message -----------
> 
> From    : owner-towertalk@contesting.com
> To      : towertalk@contesting.com
> Cc      : 
> Date    : Wed, 12 Apr 2000 23:32:06 +0000
> Subject : [TowerTalk] 2 wire Beverage query
> 
> 
> Guys,
> 
> The ON4UN book shows a two wire beverage with the two wires in a
> horizontal plane.  Can the two wires be one above another spaced by
> about the same amount (about 12")?  Is anything magic about them being
> in the same horizontal plane?

If the wires are horizontal the symmetry is mantained and each of the 
single wires, here seen as antenna wires to ground and not as part of 
the open wire line, should have the same characteristic impedance.
I always used one wire above the other with no sign of significative 
degradation in practical performances.

> Also, the version of the ON4UN book I have gives no details on the two
> transformers that are needed.  One is has a center tap and the other
> is a straight transformer.  Neither of them appear to be of the
> trifilar form.  Does anybody have details of these and/or a source for
> them?

The unbalanced step up transformer (i.e. the classic 1:9) can be a 
trifilar wound or not one and considers the beverage (to ground) 
impedance. 
The center tapped transformer is a balanced one and the secondary 
winding is build to match the impedance of the open wire line realized 
by the two parallel wires. (wires diam. & spacing)
John's book generally had enough informations to determine impedances 
and how to calculate transformers.

73,
Mauri I4JMY


> 73 de Brian/K3KO




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