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