Topband: Matching Transformer

[Jim Brown]

On Thu, 25 Dec 2008 17:51:19 -0600, AD5VJ  Bob wrote:

>Guess I am not understanding the difference of why one would use 
a 9:1 BALUN vs a matching transformer. Since his looks completely
>different than mine a transformer and BALUN must not be the same 
thing.

Bob,

"Balun" is one of those soft squishy words that means many things 
to many people, and most people who use the word are mis-using it. 
People who came up with the word call it a device that can be used 
to convert a circuit from balanced to unbalanced. That's nice, but 
it's REALLY VAGUE, and it often conceals a lot of very muddy 
thinking. 

What YOU have made is a classic transformer. That is, it uses a 
magnetic field to couple voltage and current from one winding to 
another. Some things that people call baluns are transformers. The 
also call a common mode choke a balun. And they call 
series/parallel arrays of common mode chokes a balun. 

There's material on my website that talks about common mode chokes 
in great detail. The ARRL Handbook has great material on 
transformers. 

73,

Jim Brown K9YC