RT-20 rotor will do just that. (Spendy)
http://www.greenheronengineering.com/
It was hiugh lited in current NCJ
Dave W7DPW
----- Original Message -----
From: "Doug Faunt N6TQS +1-510-655-8604" <faunt@panix.com>
To: <t3@semarg.ath.cx>
Cc: <rtty@contesting.com>
Sent: Wednesday, November 23, 2005 11:43 PM
Subject: Re: [RTTY] Novel idea?
> Date: Wed, 23 Nov 2005 20:09:33 -0500
> From: t3 <t3@semarg.ath.cx>
>
> I can't see a problem..
> except, maby the rotor cable on the upper rotor may get large doses
of
> RF while it passes between the A3S
> a simple fix could be sheilded cable..
>
> Tony
> NN1D
>
> Another fix for this would be to run the control cable fro the rotator
> up through the mast, come out the top and then down to the rotator.
>
> I like the idea, and it cries out for a couple of computer controlled
> rotators and a microprocessor to be the glue to actually calculate and
> display the radiating directions for the top antenna. I'm not
> volunteering, though.
>
> 73, doug
>
>
> Don Hill AA5AU wrote:
> > This is not directly related to RTTY, but again, I trust the
opinions of those
> > on this reflector. A great bunch of ops here.
> >
> > I've not ever heard of anyone doing this before. But it seems to
be an
> > excellent solution for me. I was going to keep this secret, but
I just can't.
> > I need some input from others.
> >
> > I'm in the middle of rebuilding my main tower. Right now, it's
at 46 feet
> > waiting for me to install the first set of guys. Why the unusual
height? Six
> > feet of tower sticks out from the concrete base. What I have
left is one more
> > 10' midsection, then the 9' top section. The tower will be at
65' when
> > finished.
> >
> > Anyway, for those following my rebuild may remember that I wanted
to install a
> > 40 meter beam. Well, I cheaped out on this idea. In order to
get something up
> > for Roundup, I've purchased a new A3S and D40 (D40 is a Cushcraft
40M dipole).
> > You have to realize that my ground crew consists of my wife and
the neighbor's
> > German Shepard. So I have to stay lightweight right now.
> >
> > Prior to Katrina, my main antenna was an A3S with the 40 meter
add-on. With the
> > D40, the rotatable dipole will now be separate from the tribander
and I can use
> > both antennas at the same time with my SO2R setup.
> >
> > Here's the kicker. I will install the D40 above the A3S and want
at least 10'
> > of separation. In trying determine if I should align the D40
with the A3S or
> > offset it 90 degrees in azimuth, I have come up with a radical
idea of
> > installing a separate rotor above the A3S. My main rotor is the
M2 RC2800. It
> > will sit inside the top section. I will then install a piece of
2" aluminum
> > conduit (mast) from the rotator up through my thrust bearing, but
only sticking
> > out of the tower a couple of feet. I will install the A3S here.
On top of the
> > conduit mast sticking a couple feet from the top of the tower,
I'll install what
> > will probably be a Yaesu G-450A with the mast mount (haven't
purchased yet) and
> > then a 10' piece of 2" aluminum conduit. Near the top of the 10'
piece of
> > conduit, I'll install the 18 lb D40. I've compiled the figures
and the M2 is
> > more than enough to rotate everything and the G-450A will handle
the D40 with no
> > problem. What I like about the G-450A is that it can be set to
stop at any
> > direction and shows an LED for overlap which I can set at 90
degrees. Also,
> > unlike the G-800S, you must push the left or right button to move
it, so it
> > won't rotate all the way around by itself. This is important
because of the
> > slack I'll need in the RF and rotor control cables from the D40
and G-450A. The
> > overlap LED will alert me that the D40 is offset. Keep in mind
that the D40
> > will only need to be rotated up to 90 degrees offset from the
A3S, never any
> > more than that.
> >
> > I've been thinking about this for weeks. I can't think for any
reason why it
> > wouldn't work. I hope to simulate the entire setup on the
ground, possibly this
> > weekend using an old CDE mast mounted rotator I have. Other than
the G-450A, I
> > have all the other hardware already. Has anyone ever heard of
this setup
> > before, a rotor on top of a rotor?
> >
> > By the way, updates on the towers on my new antenna page at
> > http://www.aa5au.com/antennas/antennas.html
> >
> > 73, Don AA5AU
> >
> > _______________________________________________
> > RTTY mailing list
> > RTTY@contesting.com
> > http://lists.contesting.com/mailman/listinfo/rtty
> >
> >
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