RC,
The relative impedances will determine which type is best. If at the
connection point of the balun output is a relatively low impedance (up
to 200 ohms IMHO) the 1:1 balun will usually serve better, but at higher
impedances, the 4:1 will be best.
Measure the actual impedance at the feedpoint with an antenna analyzer.
remember that the impedance will vary depending on the antenna and the
length of the feedline. Just because you use a feedline of 450 ohms
characteristic impedance, that has no relationship to the feedpoint
impedance which can vary from very low to very high.
If you have no access to an antenna analyzer, try them both and use
whichever tunes the best, and if the decision is a wash, use the 1:1
because it is usually a bit more efficient.
Another point is to use only the current (or choke, or bead) type balun
with a multiband antenna system - these types minimize common mode
current on the unbalanced side.
73,
Don W3FPR
bob conley wrote:
I'm showing my ignorance again!
What determines which balun you use
RC
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