[amsat-bb] Antenna separation on crossboom

[Bob Hammond]

Greg,

Do you use polarity switches on your yagis?  If you do, is it worth the
effort?

73s,

Bob
W7OTJ

On Mon, Nov 26, 2018 at 10:08 AM Greg D <ko6th.greg at gmail.com> wrote:

> That's pretty much what I did, though with different antennas.  Also put
> the AO-40 dish on the other side of the rotor from the 23cm helix, so it
> went 70cm, 2.4gig, rotor, 23cm, 2m.   Put things as far away from each
> other as you can, without running out of crossboom.
>
> I was very concerned about having the 70cm beam (uplink) so close -
> inches - to the 2.4 ghz dish (downlink), but it was fine.  Good input
> filtering in the 2.4 ghz Khune preamp, I guess.  More recently, Mode L/v
> on AO-92 seems ok too, with the 23cm antenna near the 2m, but I have a
> lot less power on 23cm than I did with AO-40 on 70cm.
>
> Greg  KO6TH
>
>
> Bob Hammond wrote:
> > I'm putting the following antennas on an 8-foot fiberglass crossboom:
> >
> > M2 2MCP8A, 143-148 MHz C{
> > Gulf Alpha 70cm 8x8 CP
> > WiMo Helix 23
> >
> > I'm not sure how to calculate the proper spacing on the crossboom.  I
> > assume the 2m antenna should go on one end and the 70cm antenna on the
> > opposite end.  Can I mount the 23cm helical antenna very near the rotator
> > without harm since it has the solid reflector behind the helix?
> >
> > Bob
> > W7OTJ
> > (was WL7CQX)
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