[AMRadio] Thank You and Toroidal transformers

Donald Sanders w4bws at comcast.net
Fri Dec 29 16:56:26 EST 2006

Pete, Amidon make a 1:1/4:1 Balun kit with the toroid and wire included.
Other wise you need info from the ARRL book on "UNUNS' which covers unbal to
unbal baluns. My 6146 final will load into 75 ohms well but some of the
solid state finals may have a problem Of course if you make the feedline a
multiple of a 1/2 wave the impedance doesn't matter. It will reflect the
antenna impedance at the transmitter end. I believe that is a multiple of a
1/2 wave times the velocity factor.

Healthfully yours,
                          Don W4BWS
----- Original Message ----- 
From: "Pieter Gerlach" <Pieter at FreeToBe.de>
To: <amradio at mailman.qth.net>
Sent: Friday, December 29, 2006 6:25 AM
Subject: [AMRadio] Thank You and Toroidal transformers

Greetings Amiable AMers,

I am a real neophyte in HAM and AM radio but i. at least recognise, that
this is the group that leads the pack when it comes to genuine knowledge and
practical experience. As the New Year approaches, i want to express my
gratitude for the wealth of information which has come my way thanks to you.
As i am a farmer who still works the land with horses, i appreciate the
importance in keeping the old, tried and time-tested ways alive; not just
for nostalgia's sake but for the time when radios and the written word might
be one of the sole sources of communication. If one of those $10,000 digital
voodoo boxes breaks down there are only a few select experts that can even
diagnose, much less fix the problem. I take off my hat to expose my bald
head to all of you!!

As an added favour could anyone tell me what sort of toroidal core i would
need to transform 75 to 50 0hms. I was given a large quantity of CATV
hard-line and read that it would be well to match the impedance to the
antenna and the transmitter. Or do you think the Pi-network in the P.A.
would be able to match the 75 ohm? I would at leat like to know which cores
from Amidon would be the right ones in case i just want to construct a few
transformers for experience sake. Thanks so much for any help you can give

Happy New Year to each and everyone!
Pieter VE1PPG
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