Hi,
Willing to try out APM antenna tracking, I needed to procure myself with a mechanical servo based pan-tilt system.
This video is both a build log and a kind of "how-to" antenna tracker build guide for those who want to try build their own.
I logically first started to look around to purchase one; my market research basically resulted in solutions that I found way too expensive for what they really are : aren't we are just talking about two servos driving a pan and a tilt plate?
However, you'd have to spend a few hundreds dollars for a complete ready-to-run pan/tilt that is able to rotate medium size antennas (for example: 350+ dollars @servocity or 200+ dollars with required accessories and 180° servos @readymaderc - without shipping, EU sales taxes, or EU custom fees).
I found it really hard to source a "1 turn" servo (there is only one model that I know of : GWS S125 but it does not seem to be produced anymore) or even a half-turn 180° servos. Most of them are standard 90° servos that were opened up to modify their internal potentiometer to extend their rotation to 180° (lots of tutorial videos on youtube explain how to do this by yourself). Alternatively, you could buy programmable digital servos but you will end up paying a high premium for them and, in addition, you will spend extra money on their proprietary programmer devices.
So the question is, is it possible to build your DIY tracker with parts you may have laying around the bench, for a very low cost ? Answer is yes, and the task can be greatly facilitated with the help of a few 3D printed parts.
I now can't wait to plug a pixhawk+GPS module on it and experiment with APM antenna tracking firmware, which will be the subject of another future blog.
PS : Here are the STL files of all the 3D printed parts used in the making of this tracker, to share with the community: Antennatracker.zip
Cheers,
Hugues
Comments
@Dronin, thx:)
Man that was awesome! Thanks for sharing!!
@Hein thx, I've also heard the tilt could be just left static which seems logical for long range (having a radio lobe that covers 30 or 60 degrees vertically). However it is more fun with it than without !
@Checkers, thx. the width is planned to be able to install a large patch antenna. I also wanted room on the back tilt plate to install a pixhawk and all of the electronics for auto tracking (the autopilot needs to be setup on the moving plate). The two servos are 180° servos. I do not know yet what will be the behaviour of Ardutracker : will it flip the PAN after 180 to achieve 360°, leaving the tilt between 0 and 90° or will both be used fully to their 180° to cover the full sky. We will see when I'll test it.