Radio Shack Antenna Rotor Theory of Operation

[KB5URQ]

I am looking for a good writeup on how the radio shack antenna rotors work. I have been able to find a very rudimentary schematic but its not very clear on what the different motor windings / configuration does.

I remember seeing an article years ago in QST about a computer control system for these.

Does anyone know of any indepth discussion on the construction & design of these rotors?

Thanks,

Jason

[K7MH]

I'd be surprised to see any in depth discussion about it, or any articles in QST about it. It is about as minimal a rotor as you can get.

What are you trying to achieve with it or use it for?

[KC8VWM]

Rotors are electromechanical devices. They use an electric motor and mechanical gears. They are encased inside an aluminum housing. The gear ratio determines the speed and torque the rotor is capable of handling. Some radio shack rotors use nylon (plastic) gears which tend to wear out faster than metal gears. The gears are coated with lithium grease because it can withstand variable temperature ranges and still remain as an effective lubricant. The grease also protect the gears from corrosion.

Not sure what you are looking for here..

[AB3FL]

The Radio Shack roor has no feedback circuit. The control really has no idea where the rotor is. It works by a synchronous motor in the control and the rotor. The indicator assumes everything is in sync, but it isn't always. There is no brake so wind can blow the antenna around and unsync the whole thing. It is possible to computer control to turn it left and right, but no point and shoot such as a Hygain with Rotor-EZ.


Tom - AB3FL

[WS2L]

I used one of their rotors to turn my Cushcraft 13B2 and Cushcraft A4496S and never had one bit of problem.

Years ago I used one to turn a Mosley TA-33Jr with a VHF/UHF vertical on top, worked like a charm.

Guess it is the only thing they sell that actually works.


http://www.radioshacksucks.biz/forums

[KF5FEI]

MCM has a variant of these on special for $50 this month. Snagged one to try out for a small 2m antenna. Thanks for the schematic -- I have been looking for one to see how the rotator and control were synced.

Then eventual plan is to use three to make an equatorial mount for a couple small satellite antennas. Looks like I'll have to add an encoder to sense true position.

[W9GB]

Jason -

The majority of US manufactured rotators use AC motors.
The KenPro/Yaesu (Japanese mfg) rotators use DC motors.

Radio Shack rotators use AC synchronous motors that run at a predictable speed.
Read this QRZ Q&A from 2009 ... should be helpful for your project.
http://forums.qrz.com/showthread.php?t=211259

READ and VIEW Doug Braun's web page on the inexpensive TV rotators sold by Radio Shack and Channel Master.
He has the schematics and PIC assembler code for a DIY project to build a new controller of this modified rotator.

PHOTOS of these rotators (Inside)
http://www.dougbraun.com/pix/rotorpix/

Description of DIY feedback modification
http://www.dougbraun.com/rotor_mod.html



EA4TX Rotator control system
http://www.ea4tx.com/products/ars.htm

w9gb

[W7MJM]

Regardless of the theory of operation, I'd stay away from the current generation of Radio Shack TV rotors. My experience, and that of others I've since spoken to, is that they're cheaply made and tend to fail after a very short period of time. Take a look at the reviews on www.eham.net or on RadioShack's own website to get an idea of their current quality.

[KC2MDP]

The Radio Shack rotator is a simple three wire circut that reverses the motor from a CW direction to a CCW direction. The control box has another motor inside to turn the direction indicator. The problem is that they are never in sync for more than a couple of rotations. The rotator itself to put it mildly is a dud..... The thing locks up, rotates at different speeds and has to be serviced constantly. Spend the extra bucks and get yourself a real rotator.

I own one, and all I can say is that I wish I did'nt.

[K8JD]

I used an Alliance U-100 to turn my 2M stacked Yagis and then my 10M monobander. It's still up there working with the 10M monobander 20 years later.
Not bad for a TV antenna rotator