[UPDATE: 27th July 2019] Stwr's Rotator v3.1 DC Motor Build July 2019

antennas
rotator
electronics

#1

Hi All,

I’m back from the dead! I got pretty excited and involved (visiting OSWC18 among others) in the Satnogs network about 12 months ago and dropped off the planet of the earth about 8 months ago. For various reasons, but mainly because I bought a apartment and went into a 9 month DIY renovation! It turns out, that takes a lot of time and energy!! But the end result is very worth it. (if you want to see some pictures shameless plug here)

Straight after that, this happened:


Yes, that is the Apollo 11, 50 year anniversary edition which I simply had to get (as a lego & space fan)

But now all that is done and I have committed to building my Satnogs ground station. I got somebody to print me all the parts 12 months ago, but they had misaligned their printer and everything came out a little too small (which is definitely not good). Luckily, we recently got an Ultimaker S5 in the office so I’ve been printing the parts myself to break in the printer!


The white stuff is the support structure that dissolves in water (PVA) which is totally awesome.

Originally, 12 months ago, this build was going to be a Stepper build, but our Satnogs friends were kind enough to hand me a nice box with the PCB board and motors for a DC version last year at OSWC18.

Anyways, My goal is to have a functioning rotator by the end of summer and more importantly, updated documentation for the community on how to build one. Which will likely make me build it twice haha!

I’ve not done much yet at the moment, but have started a bit of a test fit on some parts. This weekend will hopefully be full steam ahead!

Feel free to follow along and enjoy the ride :slight_smile:

stwr.


#2

Welcome back @stwr :tada:


#3

SAT 13 JULY Update

Been working a little bit on putting one of the units together, it is a little confusing even when following the sheets. Especially fitting the dc motors. But i’m getting there! I have to wait for some prints to finish this evening and will continue putting stuff together tomorrow.

Some photos:

Till next time :smiley:


#4

Thanks @elkos! Happy to be back :smiley:


#5

Friday 19th July Update

Hi All,

So spend another few days printing, building, cursing and what not! But the first half is officially done! Complete with little electric drill test run.

I have to say, it is a lot tougher to put together than I had originally anticipated. All of my prints were a little bit too small and I had to force (read hit really hard) a lot of items to make them fit. Even with the bearings 40mm inside diameter and 40mm outside diameter tube it was a lot of hitting things really hard with hammers! But hey, that’s really good for stress relieve, so I’m not complaining…!

Question for the group:
What is the smallest size directional antenna that is still worth using a rotator for?

The place where I can possibly mount my rotator is pretty high up on a building and quite exposed to the elements, ideally I can make my whole setup as small as possible. Now I see a lot of stations with antenna’s of 2/2.5m meters in length. I’m hoping to find something that is in the range of 50 to 70 cm’s to put on my rotator. To keep it from catching to much wind. Ideally even smaller, but guess that’s a bit too much to ask! (For reference, the 14 floor building is right next to the Mediterranean Sea) anyways, any pointers to decent small directionals are appreciated!

Next up, probably this weekend is starting and finishing the other half of the rotator and after that start with the electronics depending on how far I get.

Really enjoying the build so far, even though it is more difficult than expected. It is very rewarding!

I might add some context to the photos and edit for clarity later. time for bed now!


#6

Update: 27th July 2019 - Mechanical install complete!

I’ve spend some time today finishing the second half of the rotator unit. It fits a little less nice together than the first one, but I think it’ll do the job. It seems to spin as well, so we’ll see how it goes.

Next up is the electronics side of things. This will likely take me some time.

I’d also like to repeat my question from the last update; does anyone have any ideas on small directional antennas that could work for cubesat observations? The building I can likely mount this on is 15 floors and receives quite heavy winds about 4 days a month, so the smaller the setup the safer it is.

Thanks and please enjoy the very few photos this update.

stwr



#7

The Elk log periodic is pretty darn small and works well for VHF/UHF sats. With some clever phasing you could set up a RHCP array with two (I think). Might want to check it out.

–Roy
K3RLD