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Azimuth/Elevation Rotator for Arrow Satellite Antennas

Questions? Comments? Email KA6PUW@arrl.net

There has been a recent popularity of working FM satellites with the Arrow Satellite Antenna and a handheld radio. Its just kinda tuff doing it with one hand pointed up towards the bird. So I came up with a 12vdc simple azimuth and elevation motor unit that fits on a camera tripod.

I have a bunch of videos posted on YouTube. You can click on the link at the end of this page to see a few of them or search YouTube with KA6PUW.

Thank you AMSAT India for publishing the design in your March 2009 Newsletter.

AMSAT India http://www.amsatindia.org/Newsletter/AmsatIndia-News-March.pdf

Arrow Antennas http://www.arrowantennas.com

 

Here is a picture of the first prototype I built.

Here is another view.

 

The top part is a 2"x3" rectangular aluminum tube. The small PCB on the side is a future project (DC motor driver)

 

You can get the rectangular tube and all the aluminum from

www.onlinemetal.com

The base consists of 4 3" aluminum standoffs and some scrap aluminum cut to 2 1/2"x 3" rectangle.

Next I mounted the gearhead motor. I used a 12vdc reversible gearhead motor product number: GH12-1926 (hsiang-neng) Jameco part number 155011. It’s a 12vdc 2 rpm 3000:1 gear ratio approx $20

Jameco Electronics 1355 Shoreway Road Belmont, California 94002-4100

www.jameco.com

UPDATE

KB7RSI emailed with some news. There is a 1 RPM motor available from ServoCity.com As far as I can tell it's the same type as the Hsiang-neng but they do not give a manufactures name. They do show all complete dimensions and they seem to be indentical. I have NOT tested one yet and I will post the information ASAP. So hold off on ordering one yet. Also KB7RSI pointed out the 3" aluminum standoffs are available from them. 3.00" Part# 534-3000 $1.75 ea. I have had a hard time to locate these standoffs locally in the Los Angeles area. I am sure they are out there at a reasonable price. Thanks Harold.

It has an offset shaft from the gearhead and a 5.9 mm shaft.

The screw holes for mounting the motor are M3 x .5 metric.

Here is a picture of the top plate.

The hole for the motor is 15/32". The bottom plate has a 1/4-20 threaded hole for a standard camera mount.

You can see the 3 capend bolts for the bearing mount.

Picture of the top plate with the motor mounting holes and the capend bolts holes for the thrust bearing. I had to use a bearing because there was too much shaft play and the elevation unit would wobble.

Picture with the thrust bearing in place. The bearing race is 1 1/4 " in diameter. These bearing races can be found at bicycle shops. I simply use the capend bolts to hold the bearing in place. I found this one at:

All Electronics Corp 1 888 826 5432

14928 Oxnard St, Van Nuys California 91411-2610

www.allelectronics.com

CAT# BR-5 $1.25 1.27" OD 0.66" ID

UPDATE

I changed the bearing support so you don't have to drill and tap 3 extra holes and screw in the cap end bolts. I used 2 washers or a 5/8" OD diameter spacer from ACE Hardware.

Here is picture with the 5/8" OD spacer installed.

 

Next is the elevation motor mount.

The 3/4" square stock was added as a cheap support bearing. Its possible to do without this piece. The small piece of aluminum on the bottom is for attaching the azimuth motorshaft.

Here is another side view with the elevation shaft in place.

Here is a side view showing the shaft hole.

The shaft is the hardest part to make without access to a lathe and mill. Its possible to do this with a plain drill press. One end of the shaft is drilled out to 6mm to fit over the motor shaft and the other side has a flat spot milled out to accept the antenna mounting plate. The shaft diameter is 12.5mm

Here is a photo showing all the parts.

 

Simple Motor control with a DPDT switch.

 

 

 

I have a Youtube link if you would like to see it working with a 12 vdc H Bridge and Parallax BS1 Basic stamp. Any help in programing P basic for AO-51 tracking would be appreciated. I am getting a lot of questions on the H bridge, I am using a JCMINventures.com Dual motor H bridge. You can use any similar type or make your own.

YouTube link http://www.youtube.com/watch?v=lG540bPebro

http://www.youtube.com/watch?v=HEvppIyUXOU

Whats next? 02/16/2010

Harold KB7RSI has made many suggestions and will be testing one unit. These motors have great torque - on the ServoCity motor page they warn if the shaft stops turning damage can occur in the reduction drive gears. They are very strong. I am getting requests to sell a complete unit but I am more thinking to make a partial kit available for a short time. So far I am unable to find a source for the 2"H x 1.25"W x 1/8" square U bolts. I need to find a tapered head M3 METRIC machine screw source nearby. There would be restrictions in payment because I do not want to deal with checks or cash. So I am thinking about putting them on EBAY with PayPal check out only. These partial kits would have the intention for you to try and hook it up to a tracking controller. Any feedback would be appreciated.

 

Here is Harolds KB7RSI's bearing modification

 

Bolts instead of spacers that you can get from any hardware store

So what else is up? Well I got some email about Mode V/S. The mounting plate for the 2/440 yagi has to be made longer so you could attach a small 2.4ghz antenna or a California Amplifier 130099 type downconverter. Pictures soon. Some comments about using the azimuth elevation rotor with a tracker unit. Some require feedback for position. Some of the PIC types may use a 10K pot. (any potentiometer could be used) I need to come up with a pan/tilt type version. Please send me your ideas and comments.

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