[NLRS] Elevation rotators for small stuff

[Doug Reed]

If I was going to do it, I was thinking of those 2' dishes I handed
out, swap in a 10GHz feed and mount the transverter electronics in the
original box on the back of the dish. I wanted to get it down to just
power and an RG58 cable to the IF radio in the car. But the size,
weight, and wind load would be significant.

If you have $1200-$1500 (or more) to spend, you could look for one of
the folding dishes they sell for motorhomes. Some of those are
motorized and self-aiming, not just a hand crank on the inside....

The DSS dish is seriously cheaper and smaller than either of these
alternatives.

73, Doug Reed, N0NAS.


On 9/11/13, tosca005 at umn.edu <tosca005 at umn.edu> wrote:
>
>
> Another approach altogether came to mind. I am reminded of a toy (game)
> that I loved as a child, called "Space Tilt". It apparently was also sold
> under the name of "Labyrinth".
>
> http://boardgamegeek.com/boardgame/6546/labyrinth
>
> The basic idea is that you have three nested square frames. The outermost
> one is fixed in place, e.g. attached in some way to the roof rack of your
> rover vehicle. There is a swivel between the outer frame and the middle
> frame, at the front and back, which allows the middle frame to tilt left
> and right (relative to the vehicle). Thee innermost frame has swivels
> between itself and the middle frame, so that it can tilt front and back.
> The innermost frame has a platform on its top that can hold a conventional
> antenna rotator.
>
> Simple gearing at two of the swivels, say front side and left side, to
> electric motors would execute the tilting Up/Down in the front-to-back
> plane and the left-to-right plane. A three-axis magnetometer could measure
> the tilt and an Arduino could make the tilt measurements and control the
> motors to get it all level. A second unit on the rotator mast (or linked to
>
> it rigidly in some manner) would allow an absolute magnetic compass bearing
>
> instead of relying on the vehicle-relative bearing indication of the
> rotator controller. Or you could install your antenna(s) pointing North and
>
> always park the vehicle with its front pointing North so the rotator
> controller matched the actual direction(just kidding).
>
> https://www.sparkfun.com/products/10530
> https://www.sparkfun.com/products/9815
>
> If I wasn't so busy with preparing for the next two contests, I'd build a
> scaled-down mock-up, maybe out of balsa wood, just for grins to demo the
> idea. If I was building it for real, I'd likely use square aluminum tubing
> and/or square aluminum U channels for the frames, and fabricate some sort
> of aluminum sheet metal mounts for the electric motors.
>
> As I mentioned, if I was building this project, I'd use a conventional
> azimuth rotator (most likely my Yaesu G-450A rotator) for pointing. Since I
>
> have one already, I would consider using a Yaesu G-500 elevation rotator so
>
> that instead of the limited tilt of the platform (reserved for just getting
>
> the platform level in spite of the terrain on which you park the vehicle),
> I would have the ability to turn the dish to the vertical position (dome or
>
> birdbath) for driving, and then horizontal with full elevation control for
> operation. That would involve a cross-boom, and it would make sense to put
> two dishes, one on either side of the vertical mast. For the 10G contest,
> the most sensible would be 10G and 24G. For SBMS or a VHF or UHF contest,
> 10G and 5.7G (since I don't own any 24G equipment and have no plans to go
> there anytime soon).
>
> Even better would be if there was an inexpensive source for radomes that
> could enclose the dishes all the electronics! But I don't know of any such
> sources.
>
> Anyway, just more food for thought.
>
> John
> W0JT
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