RadioBanter - View Single Post

Owen Duffy · October 7th 09, 10:07 PM posted to rec.radio.amateur.antenna

steveeh131047 wrote in news:0a13ea69-ccea-4555-a5c8-
:

It works well.

I needed some Zo=25 ohm for a 1:4 balun (12.5ohms50ohms) and simply
used parallelled lengths of 50 ohm for the windings.

If you are talking about a balun made with an electrical half wave of coax,
you may be hard put to observe the difference between using 50 ohm or 25
ohm line. If the load was an ideal resistor, using the 'matched' Zo gives
least loss and best bandwidth, but on a narrowband antenna, the balun
bandwidth is less an issue, and may even compensate the antenna (depending
on the chosen Zo).

The OP's application to a quarter wave line is sensitive to Zo though, and
it works fine, but it is quite important to bond the shields effectively at
both ends of the line.

Owen