"ve2pid" wrote in news:1174098010.745176.35010
@e65g2000hsc.googlegroups.com:

Hi to all,

I read somewhere that, in the case of Yagis, ''in the range of 25-35
Ohm you get the
best balance between gain, pattern, bandwidth and element currents.'''

Is that true? And if so, I would like to have the theoretical
explanation behind this.

I don't understand why there is such a relationship, if there is.

Yagis are often designed for a feedpoint impedance that is relatively
easily transformed to 50 ohms for the main transmission line.

A quarter wave transformer from 28 ohms to 50 ohms is relatively easily
made from two parallel 75 ohm lines. Perhaps that is the attraction to
the impedance range you mention.

Owen