[NLRS] Elevation rotators for small stuff

[tosca005 at umn.edu]

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