[Antennas] balun question

[John Tait]

Hi John...

Subject: [Antennas] balun question


> I have a Van Gordon 4:1 balun that I use on my
> homebrew G5RV antenna.  It goes between the 300 ohm
> twinlead and the 75 ohm coax.  While doing some
> checking on my different coax runs this weekend,
> noticed that the coax for the G5RV is shorted between
> the center pin and the braid.  Traced the short back
> to the balun.  Is this normal for a 4:1 balun-to have
> the center pin and outside connector shorted, or did
> mine go bad.  Any feedback is appreciated.

   It is normal to get continuity across the 4:1 balun... It is NOT normal
to get continuity across the coax on its own.. It is also not normal to use
a 4:1 balun on a G5RV..  The whole point of the G5RV design, is that it has
a low impedance at the junction of the coax and 300 Ohm twinlead. If you use
the 4:1 balun, you may as well dispense with the ribbon,  and put the balun
at the centre of the antenna instead. A 1:1 current balun however, probably
would be beneficial at the junction of the coax and 300 Ohm twinlead.

  73
     John EI7BA