Topband: Binocular transformer design

[James Wolf]

-----Original Message-----
From: topband-bounces at contesting.com [mailto:topband-bounces at contesting.com]
On Behalf Of w2pm at aol.com
Sent: Sunday, January 04, 2009 8:43 AM
To: topband at contesting.com
Subject: Topband: Binocular transformer design

I am making a few tansformers for a  75 to 500 ohm K9AY loop which per 
W8JI's design in ON4UN's book call for a 5 pass secondary - which is 2 
1/2 turns through the binocular core.  The problem however is this 
places one end of the secondary wire at an opposite core opening from 
the other end of the secondary.  My concern is that if I bend the one 
wire around the outside of the core to make for a reasonable connection 
with the other wire, characteristics will change since the wire will be 
necessarily in close contact with the core wall.  I can devise a simple 
enough mounting and connection physical arrangement for connection to 
the antenna with this awkward wire configuration but wondering if that 
is necessary?

I've made lots of these for 16:1 applications but in those models the 
number of passes for both primary and secondary is even and thus the 
two wires for each winding are adajacent and symetrical.   I guess I'll 
just go ahead and make one and measure it to see what effect this 
configuration may have - which is easy enough to do, but just wondering 
about this situation which is unique to binocular forms ..

73


Pete W2PM
_____________________________________________
Pete,

The turns ratio from 75 to 500 ohms is 2.58.
If you use 2 full turns on the primary and 5 full turns on the secondary
that will put you right where you want to be.

Jim, KR9U