[QCWA] Baluns part 8

[Jeffrey D Angus]

Other values.

"But I want to match 300 ohm twinlead to 50 ohm coax."

Ok, that's easy enough, 6:1 ratio. You're NOT going to
do that with a choke balun. That is limited to 1:1, 4:1,
9:1 etc.

A 6:1 impedance transform is going to require a 2.45:1
turns ratio on a voltage balun.  A reasonable method to
accomplish this is to use two cores. First a voltage type
to go from 50 to 300 ohms, then a 300 ohm 1:1 choke
balun to make sure the antenna currents are balanced.

You'll notice I seem partial to choke type baluns. There
is a reason for this. They force the antenna current to
be the same on both sides of the feed.

This eliminates a majority of problems with stray RF
due to the feed lines radiating.

This is even more important when you have issues
with a good solid RF ground right at the transmitter.
(In my case, I'm up on the second floor and 20 some
odd feet from ground such as it is.

Jeff-1.0
wa6fwi