Satnogs - All Metal "Box Mountable" Rotator

Nice. Don’t stop now :slight_smile:


The rotator move and the sun shine :wink:


Antenna Upgrade ! (wimo x-quad 432mhz) obs are really better ! but it looks like 15mm fiberglass axis isn’t good enough to support all this weight…
V3 (work in progress) will be with 30mm Aluminium tube !


V3 coming soon !


Hey! Nice design!!:rocket:
I have some questions to understand better the design:

  • Do you put it inside a box like the previous version?
  • Where does the bearing of worm gear is mounting (the side with the pulley)?
  • How do you mount the mast for antennas?
  • Do you have any provision to put encoders for position feedback in the output (i can help you!!)?
  • If the design uses an aluminum box and somebody doesn’t find the same size, do you have any provision to put the mechanism in a different size box?



Hi @azisi

Yep for this time the design is made to be put in a box (Hammond 1550 H i think) but in the same time i’m working on another one which work with a special box :

On the “market box” version, the block bearing is mounted on this part 12

Which make the connection between the stepper and the worm rod

For the mast and for the antennas,

The rod (in black) is fixed by 4 screw to the worm gear/axis (brass color)

I would really like tu put encoders, i didn’t had the time to think to them, for this time i just added optical endstop in my design, but, yeah i could need some help to know how to use them !

About this different box size :

The mechanism is in 4 parts
1/ Axis/worm gear + Ball bearing for elevation
2/ Stepper + Timing pulley + Worm rod, (which is mounted in only one “solid” block

And the same for the azimuth

So basically you can mount it a bit as you want (for an example you could just mount it on a plate), the only limit is the length of the axis/worm gear (which is the same parts)

If it could help, it looks like that once mounted in a box



Seems that has some points which are difficult in fabrication like the motor mounts (i think that are embedded in box). Also for azimuth axis, it is better to use a thrust bearing instead of ball bearing( the top bearing). The mount of azimuth ball bearing (the one inside the box) it needs more support because takes all the weight of rotator and antennas. Also, you could consider to use bushings or plain bearings instead of ball bearing (for 3 ball bearing that are mounting in sides of box), because in this application the rotation speeds are low and the bushings or plain bearing could handle heavy weights.

The pulleys for timing belt are going to high maybe this is a problem for tension of timing belt and the stepper motor must have a long axis. Why are you using so big ratio for timing belt transmission? Which is the ratio of worm gear box?

I think that you need a more powerful mounting system either like Yaesu G5500 or SPID rotator.

I like a lot the idea with the different size of boxes. Have you estimate the cost of
the axis with embedded worm wheel?

I seems that in non-custom box design it exist space to put encoders for position feedback.

Nice design!! Keep going!!! :rocket:


Hi @azisi thats really cool because maybe you dont wanted to but you really give me the answers to question that i was asking to myself !

Yeah i thought it would be a big problem, but the design was only a poc for me so anyway I should design it in 2 parts

I was also considering this 2 things (i just need design them now :wink:

I’m not pretty sure that i’ve well understand what you mean, are you thinking that the tension is going to be too high or ?

I’m considering 2 options the first is 16:40 and the seconde one is 16:60 (one the first image this is 16:40 and one the second one this is 16:60) I’ve juste wanted to have the biggest ratio as possible in the smallest space

Did you well understood that the 4 screw are through the 2 tubes ? I was thinking this was the most powerful mounting possible, but if you say that U bolt is better I believe you !

28$ / pcs for 2 pcs — 24$ / pcs for 10pcs — and 14$ pcs for 100pcs (price given by this instant quote system)

Thanks for your ideas and your help !



Think about the torque that produced from the tension of belt and how wear the bearings of stepper motor. Also how easy you can find a source for stepper motor with big axis.

Also, you need to consider about the rotation speed, take a look here ( Mechanical Analysis [WIP])

No i didn’t understand :slight_smile:, but due to antennas load the holes would be open more (the brass axis with gear).

So you are using standard tooth profile and module for gear box, because if not use you have additional cost due to custom tooling for machining.



Hi All,
After weeks of reflection, I must assume that my design isn’t the good one.

The design was successfully working with a tiny antenna. But with this antenna the result of the station wasn’t better than with a omni antenna and without the rotator, so not really usefull…

Then i bought a very good antenna, which was as beautiful as it is heavy, and and right away all the problems happened, and nothing was reliable anymore.

So what is the best solution ?
Spenting a lot of time to build a rotator for A to Z which can only carry a small antenna ? I don’t think so, it was a very interessant work ! but this isn’t the good solution…

For this reason, this project, in this first iteration come to an end, but something else is coming ;

I definitely needed something more reliable, but I still didn’t want to buy a commercial rotator, I really wanted to keep the spirit of construction. Inspired by everything that has already been done (SPX-02 for exemple) and what works really well, SuperAntennaz was born.

The main part is this one : Réducteur de vitesse de moteur à vis sans fin, sortie 14mm 5:1 80:1, NEMA 23, DC, RV030 | AliExpress

The number of parts is really small, there are just 3 aluminium plates, and two adapters to fix the rotator on the masts.

I know that the first(s) objectives of my project aren’t respected anymore, but if this design interest you too, just let me know, and i will continue to put update on that thread !




Still interested! Please keep sharing your progress.


Work in progress !

For 80$ I’ve get this parts machined

The first one is for the connection between the azm motor axis ( and the 35mm Aluminium Mast

-The second one is for the connection between the two Reducer (RV030 Réducteur de vitesse de moteur à vis sans fin DC, RV030, sortie 14mm 5:1 80:1, pour moteur NEMA 23 | AliExpress)

-And the lasts one are the connections parts between the “double” elv motor axis (, the parts is done two time, one for the left side and one for the right side, and finally we fix this flange on the plate Bride en acier galvanisé, 3 14mm, haute dureté, couplage d'arbre, bride rigide, couplage, Guide moteur, roulement d'arbre | AliExpress

I am now waiting for the aliexpress delivery of the last elements to start the assembly…


So two RV030, Two NEMA23, and a couple of parts to attach to antenna? Pretty slick!

What gear ratio are you looking at on the RV030? (ans: 80:1 in comments above)

What watts/amps on the NEMA 23?

What are you thinking for the software driver?

1 Like

Indeed, that’s the purpose of making it very simple :wink:

I use 2.8A NEMA23 stepper motors (56mm and 1.26Nm),
For the first test I will use a 12v 100W (34W for 1 Stepper) power supply, and stepper drivers which can cary up to 4.0A peak, and 9 to 42 VDC.
I’m now waiting for the last part from aliexpress…

For the soft I will still use Satnogs with a Raspy and an Arduino, but nothing stops me from removing the raspberry and connecting directly to a pc to use GRpredict.

Thanks for you interest !


And… All is working pretty good !


Bravo ! Superbes résultats ! Great job ! I’m very impressed ! 73’s Martin 9V1RM / F8UKP


Thx Martin !
Some better pictures…
And to see it in action : SuperAntennaz - Rotator - Operating Version (Spring 2020) - YouTube


After few days “on” mechanically everything works, which is good, but I now have other problems with the signal reception but anyway.

So what’s next ?

Three things can be improved :

  1. I would like to test something different for the bracket, which would simplify the assembly-disassembly and make it more reliable, with a laser cut and bent plate, which costs about the same price as the old bracket, or even a little cheaper.
    And then on this bracket we will mount that type of jaw : Bride pour tube Ø 40mm

  2. The Optical Endstop are as precise than shit in day light, so there are 2 solutions, the first, (the one I’m actually working on) is to change a bit the design, to stop daylight switching off the endstop when he need to be switched on. And the second possibility is to finally switch to encoder, which will offer the possibility to use DC motor too.

  3. To facilitate the build, I’ve done a small come back on the way reducer are mounted together, there was only one horizontal plate between them, which will be replaced by two vertical plates

A Few people contacted me to ask how they can build their own Rotator. What I purpose to everyone who want to build it is to speak about the project to people who may be interested as you. I will create soon a registering list so that then as 5 or 10 people are registered we can make a grouped order for machined parts, which can reduce part costs from x2 to x10. I may then create a kit with all the machined parts, the screws, and build advices, if you want

One more time feel free to ask me any question you may have !


So happy to see your progress! My worm gears have arrived, waiting on stepper motors. Following in your footsteps.


What an impressive work dear @Yohan_Hadji

My congrarulations.

73 Oliver DL6KBG