Greetings! This is my first post.
I’m a student at a university in south florida, USA. For my senior project my team and I are building a communication system for a cubeSAT. After some googling I found the SatNOGS Rotator and decided this would be cost effective and fun to build!
Thus, I began reading through the instructions and BOM. Unfortunately, a lot of the parts required for the rotator are not sold near me. Also, the distributors linked in the BOM spreadsheet are half way around the world and the huge shipping costs are causing frustration to say the least.
Has anyone built the rotator here in the U.S.? Which version did you use? How much did it cost? What modifications did you make? Is there a guide for this?
Thank you all very kindly.
Ah, the old metric / imperial problem. I’m sure there are a few that have been built in the US. Corey might be the best person to talk to (he has put his in the gallery here). I imagine that a few tweaks could solve the issue rather than a redesign. Price should be roughly the same regardless. It all depends on what you can lay your hands one.
Generally the V3 is the one to go for. But also don’t discount a no rotator setup if you have a pass friendly location there is a bit more info here. Great for getting to know the way SatNOGS schedules. There may also be other ground stations that you could make use of to supplement your own rather than having to rely on a single ground station. After all thats one of the cool things about SatNOGS.
v3.0-32mm has a folder with the appropriate imperial sized parts for imperial PVC:
See this post as well: US v3 part sources
First of all, thank you both for your timely responses.
Interesting. What would you consider a pass friendly location? What sort of window of time would we be facing vs. with a rotator set up? From what I’ve gathered, a normal orbit window for LEO satellite would be about 10 minutes, and a rotating ground station would enable us to access the transmission for most of that time. How long is the download window for a no-rotator setup if using a turnstile or egg-beater antenna? I plan to simulate these situations in the future using STK for a better idea.
Where can I learn more about how the scheduling/passover prediction works? I would really like to dig into that information to learn a little bit more about how that functions.
I’ve seen these files. Is that all that needs to be modified for the PVC? What size PVC will this modification work for? Would I need to purchase a different bearing?
This post is fantastic! I’ve found almost everything that is listed there. All that’s missing for me now is the “Hidden corner connection slot 6” (unavailable at the link provided in that post), and I’m also missing both the large and small timing pulleys (unavailable at the links provided in that post). I’m going to continue looking for these but I was wondering if you have an alternate source for these 3 items?
Thanks both of you for your help!
EDIT: Actually just found the pulleys on adafruit! Still need to find those hidden corners…
I’ll have a go at answering…
Pass friendly - To me this is about where you plan to site the ground station. Your local geography. If you don’t have a good view of the sky then your pass will be potentially shorter than one with an open view of the sky. So a fixed station in an urban environment with lots of noise is going to yield worse results than the magic station on top of a high hill in a RF quiet location. The length of time that a pass is visible is based partly on that and partly on where the sat is in the sky. i.e. overhead pass will be longer than one that just pops over the horizon fr example. How long is that string?
The stage environment is a nice safe place to play about. Also have a look at the stand alone software GPredict, It drives the scheduling.
I ended up getting my hidden posts from Alibaba. It was a bit hit and miss but they eventually arrived and are fine
Hi @future-spaceman – one other thing I’ll mention is that Dan White has begun a Gitlab repo that allows changing 3D printer files for rotator parts to fit different tubing sizes (ie, resize things for Imperial). I’m not sure of the current state, but it’s definitely worth a look – last time I checked, it seemed it would be pretty straightforward to resize any parts that might not be in that repo already.
Hope that helps, and keep us posted on the progress of your station!
Thanks for those links! I will be plugging into the SatNOGS network. I want to have better control over the ground station in the event that I want to follow a cubeSAT that is not listed as an option, or if I want to follow a cubeSAT during a high altitude balloon test.
Thanks a handy tool Dan White has developed. I may need to use it if I get stuck during my build! Thank you.
Between Banggood and ebay I got most of the components, all with free shipping. Enough to do a first build, and often with parts left over. (It was easier to buy 20 of things that I needed 6 of). I just had to allow 2-3 weeks, which wasn’t hard as I needed to schedule print time. I wouldn’t want to run some of these bearings at thousands of rpm ($2 for 10 pack) but for this task, more than sufficient.
I’m in the process of building a 3.1 version. Got most of the hard stuff from China. I modified the imperial 3.1 files to make it fit imperial but have yet to put it together. Still need frame parts