I just returned from the UAV Day @ The Fleet Center here in San Diego. Quite a few folks swung by the San Diego DUG table and asked about the antenna tracker I built. Joe Aletky from 3d Robotics asked me to share the build of material for the antenna tracker. There's the Antenna Tracker wiki but I wanted something a bit heavy duty for the field!
The parts list is mostly sourced from ServoCity and cost me about $200 to build at the time. From my understanding the price on the servos has gone up a bit.
You will need:
2 - Aluminum Channels, one for the antenna rail and one to hold the servo where you bolt down to the tripod. I'm running a 15" bracket and a 4-1/2" bracket.
2 - RobotZone channel mount gearbox, I went with 360 degree CLOSED LOOP servos. The ratio I used was 3.8:1.
2 - Servos. I went with HS-5485HB servos. If you're not good with a soldering iron, let ServoCity do the servos for you.
From Pololu you'll need:
The rest I'll share in pictures since they describe how I did it better than I can. I will STRESS the same thing that the wiki states. Keep your tracker clean and the wires out of the way. The gears have no mercy when it comes to chomping wires and fingers!
Back side of the antenna rail. I'm running a 900mhz patch and the BOSCAM 5.8 receiver with TrueRC crosshair antenna.
The video RX attaching to the Crosshair antenna. The bracket I took off of another antenna.
3dRobotics 'Ground' module. Soon to be swapped out with a RDF900! Hyperlink is now known as L-Com.
Here you can see the Pololu servo controller, the Channel C Bracket, the 4-1/2 channel and one of the monster servos. Again keep your wires clear! The servo will eat them! I drilled a hole through the tripod head (It's a cheap one) and bolted the channel down to the tripod head..
Up close of the Servos for Pan and Tilt. Here you can see the 90 degree hub mount bracket.
I use a regular BEC to power the servos from a 12v battery. Usually I'll draw this power from my lead acid ground station battery. I have two USB cables. One from the Telemetry and the other from the servo controller that plug into a USB hub. Those then plug into my laptop and tie into Mission Planner. From there everything is controlled via Mission Planner and the telemetry coming down from the plane.
Comments
I'm working on my setup... after a couple of tests I found that I have to balance the antennas properly and find a centre of gravity, because on some angles a tilt servo makes hf sound like working too hard. But once I found CG, it works just awesome. And I have to say that my antennas are crazy heavy (+battery +balance weight) - 1.3ghz helical 7 turns and 915mhz patch
Very Clean! I see you used the hollow shaft servos as well. I'm going that route later this summer when I redo my antenna tracker.
Sure. My wiring is kinda everywhere. because I just finished it. But it works perfectly with no wires coming even close to the gears.
https://fbcdn-sphotos-f-a.akamaihd.net/hphotos-ak-ash3/t31/1907737_...
https://scontent-b-iad.xx.fbcdn.net/hphotos-ash3/t1/1185093_1015229...
https://scontent-b-iad.xx.fbcdn.net/hphotos-prn1/t31/1614498_101522...
https://scontent-a-iad.xx.fbcdn.net/hphotos-frc3/t31/966178_1015229...
https://fbcdn-sphotos-a-a.akamaihd.net/hphotos-ak-frc3/t1/1507014_1...
Max LEe your setup is awesome! Can you post detailed photos?
Huge thanks to this thread, I have my antenna tracker rolling:
https://www.youtube.com/watch?v=V5TE8fdexHI
It is a gigantic 26dbi Laird tech 5.8ghz antenna I got from ebay for $20, and a 900mhz yagi.
The SPG785 setup from Servo City manhandles the antennas like it owes it money! Tilt servo have excess of 1000oz-in of torque! With my calculation, without counter weighing, my antenna exerts around 250in-oz of torque on the servo arm at full horizontal. :) Plus they have holes in the center of the gears to allow for clean and easy wire routing.
I used different servos though. SPG785A-5.0 (7:1) for tilt and SPG785A-BM (3:1) for pan.
Andrew P. That servo is same as mine, and if mine can throw around a ~3 pound antenna hanging 8 inches off the servo arm no problem, that one will also do the same. It would be overkill, which is good :)
What do you think about this gearbox - SPG785A-CM Servo Gearbox (utilizes the Hitec HS-785HB) - should it be enough to work with 2 antennas: 1.2ghz Helical (7 turns) + 915mhz patch?
Ahh. crap just figured it out, and deleted my comment, and you guys already have replied! thank you very much!
make sure you tick rev before connecting.
In mission planner you should be able to click the Rev check box.
This looks like it needs some of that hobby king wire mesh. That would keep the wires together, helping protect them from the servo gears... Also, there's something about it that makes every project look really professional.
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