[RTTY] Novel idea?

Dave W7DPW w7dpw at comcast.net
Thu Nov 24 02:49:56 EST 2005


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 at panix.com>
To: <t3 at semarg.ath.cx>
Cc: <rtty at 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 at 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
>    >
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