There’s a magnificent constellation of spacecraft in orbit around Earth right now, many sending useful data back down to the surface in the clear, ready to be exploited. Trouble is, it often takes specialized equipment that can be a real budget buster. But with a well-stocked scrap bin, a few strategic eBay purchases, and a little elbow grease, a powered azimuth-elevation satellite dish mount can become affordable.
The satellites of interest for [devnulling]’s efforts are NOAA’s Polar-orbiting Operational Environmental Satellites (POES), a system of low-Earth orbit weather birds. [devnulling] is particularly interested in direct reception of high-definition images from the satellites’ L-band downlink. The mount he came up with to track satellites during lengthy downloads is a tour de force of junkyard build skills.
The azimuth axis rotates on a rear wheel bearing from a Chevy, the elevation axis uses cheap pillow blocks, and the frame is welded from scrap angle iron and tubing. A NEMA-23 stepper with 15:1 gearhead rotates the azimuth while a 36″ linear actuator takes care of elevation. The mount has yet to be tested in the wind; we worry that sail area presented by the dish might cause problems. Here’s hoping the mount is as stout as it seems, and we’ll look forward to a follow-up.
It would work for us, but a 4-foot dish slewing around in the back yard might not be everyone’s taste in lawn appurtenances. If that’s you and you still want to get your weather data right from the source, try using an SDR dongle and chunk of wire.
[via r/amateurradio]
oh God I love the sound it makes.. SO SIFI.
great job. All you need now is your own micro satellite.
But the things you could do. Mont it on your roof with a reg mic. as well and listen in on your in laws 4 miles away.
That is so cool and it looks like it is fast anuff for low orbit sats. or the ISS.
Geat job.
But oh, doesn’t that linear actuator need a drop of oil or a litre?
Sorry to post negatively about such a great project. It’s not workshop envy at all, my workshop could be just as good as this! I just need to add some things. Perhaps I should start with a vice – oh and I will need something to bolt the vice to perhaps – as well.
This is something that I have been looking into for a while. (ISEE-3 bit me good)
I have been sketching something that has to scale a bit though, because I am looking for surplus 6-15 foot dish(s) for my backyard.
The part that I am looking into though is the relative lack of good information on alt-az logic.
Everything seems to use ancient PIC controllers drawn up in the ’90’s for ham radio, or something new that needs an arduino and “just works.” Its hard to find the actual foundation and learn how they track, and convert that to position info.
Start reading celestial navigation mathematics and about all the kepler elements. Those two systems will explain all the math between surface coordinates, time, and angles to an object in the sky.
Here is my github repository: https://github.com/twdeckard/AE-35
Check into the orignal PLAN13 code which has been ported to everything from a Commodore 64 to an HP41 calculator: http://www.amsat.org/articles/g3ruh/111.html The comments provide some insight into how the calculation is performed.
Here is the QRPTracker which is arduino based and derived from PLAN13.
Regards
Todd
Next make a dome for it so the wind doesn’t matter.
Not much to be gained by posting links to sites you have to join to be able to see is there?
There is an untapped market for an affordable mechanical kit to do this (e.g., $500 or less with motors but without antenna, encoders or electronics). With decent inexpensive jack-screws available the elevation is pretty easy. The azimuth is a but more tricky. Maybe do the azimuth with a jack-screw also, after-all you’re not going to get an affordable solution with a true rotary coaxial joint, so just accept near 360 degree before wind-up. By the way, the antenna in the YouTube video doesn’t have a rotary joint either.
Nice. What is the make/model of the antenna gimbal? Here is a youtube video of my homebrew unit which also uses the elevation over azimuth unit salvaged from an RV satellite TV unit. https://www.youtube.com/watch?v=FjZ26e1FFKo
Ultimately I will need something more robust to steer an array of antenna’s for EME and I am using this platform to develop the drive software. There are motorized gimbals for outdoor security cameras that are not expensive and may provide more umpf.
Thank you for posting. If you want any technical detail on my project contact me.
(I responded too quickly and did not realize your Az/El mount was engineered from scratch — very impressive). I appreciated the IMGUR postings. Alas, I don’t have your skills and am canvasing for something I can adapt. Very cool. I can offer that my next iteration will probably be a pure X-Y rotator as I lose the pure overhead passes.
Best
Todd
Is there a guide as to how this mount was manufactured and coded? Would love to make one of my own and use a 4.5 metre dish.