The whole subject of running coax directly to balanced line has to take into
account how long each type of feedline is. If you had a short piece of
coax less than 1/4 wave long, or if you had an exact electrical half wave of
coax, you could probably get away with the non balun approach. The reason
for using a balun is to avoid RF getting onto the outside of the coax and
radiating or then causing RF on the coax coming into the shack.
If you fear balun saturation, etc. you can always use some ferrite beads on
the outside of the coax to block RF going the wrong way, (onto the outside
of the shield). Coiling the coax into a cable choke accomplishes the same
decoupling.
The late W5YR had great success simply putting beads on a short length of
coax, and connecting that directly between his coax output of tuner and his
balanced transmission line feeder. I greatly respected George's knowledge
and long RF experience and when he said it worked for him, I was convinced
it was a simple and useful technique.
-Stuart
K5KVH
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