Topband: Center support on K9AY Loop

[Michael Tope]

> Sounds reasonable. You probably have severe pattern distortion and
> you can probably detune the tower and reduce it. You simply must add
> out-of-phase currents in the shunt that are exactly equal and
> opposite to the current in the tower. That generally means tuning for
> resonance in the gamma if it is a short gamma and if the tower is
> less than 3/8th wl long electrical length.
>

Tom,

Actually there is no gamma arm currently. We are not shunt feeding
the 45G tower (yet). The TX antenna is a low 160 meter dipole
that is sitting at the edge of the cliff another 100' or so in the other
direction (away from the K9AY array). If I add the gamma arm
to the 45G tower (for detuning purposes) how would I go about
adjusting it for minimum interaction? Would it be better to excite
the whole tower parasitically with a nearby whip and transmitter
and then use a current probe loop around both the tower and
gamma arm to adjust the gamma tuning for minimum overall
tower current, or would it be better to excite the tower directly by
connecting the gamma to an MFJ-259 and tuning the gamma for
minimum reactance on the impedance analyzer?

Thanks!

Mike, W4EF...............................