Custom rotator with satnogs firmware

SatNOGS Hardware
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I am really enjoying the satnogs network after getting the nudge at their Dayton booth, have had some success with omni antenna (moxon turnstle), rtl-sdr (lna is on order) and a ubuntu notebook.

Also at Dayton, I found in Meldelsons surplus a camera az/el platform with one missing stepper, really cool sliprings (az could go around forever it it were not for the antenna cable) and have it working with gpredict and satnogs client now, pointing, still have to make a yagi and again waiting on the lna4all. It won’t handle a really heavy load or live out in the rain.

Anyway, had one bizarre issue with the rotator - using a custom version of the arduino stepper code for the v3 rotator controller (removed the homing, temp sensor, i2c etc) - which basically works. I can connect to serial port and type “AZ10 EL10<ctrl-J>” and it goes there, all over the hemisphere OK.

Then I can start rotctld with: rotctld -m 202 -r /dev/ttyUSB0 -s 19200 -T 127.0.0.1
and connect to port 4533 with netcat (nc -v 0 4533) and type “P 10 10” and again moves all over OK.

The weird part is gpredict / satnogsclient - no tracking. Put a debug print in the Arduino and somehow it is getting a ‘!’ prefix, like: !AZ197.6 EL44.3 UP000 XXX DN000 XXX

I even used tcpdump on the loopback and looked at the traffic with wireshark and can see the commands from satnogs clent are good, like: P 156.104000801 32.942941518

SO I cannot figure out where the spurious ‘!’ comes from - as a workaround I just put in the arduino a delete function and: if (buffer[0] == ‘!’) delete_char(Data,0);
and gpredict and satnogsclient are working just fine with actual passovers now - weird.

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Thanks for stopping by at hamvention - you mention Mendelsons, were they back this year? I know last year they did not come. I didn’t have much time in the flea market so maybe I missed them this year.

As for the ! that’s weird, I checked hamlib code and it shouldn’t be injecting the ! either. This may be similar to behavior in Arduino problem with gPredict and rotctld

You might try running rotctld in verbose mode and pasting some of the responses there. In the meantime I’ll poke @azisi and @csete for their thoughts.

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Mendelsons had a booth at the hamvention and I also made a pilgrimage to their store downtown where was found the camera az/el base for my 435MHz antenna project.

Speaking of which, just spotted this interesting az/el project on twitter (#arduino) using a couple of gear motors looks real interesting: http://www.sarcnet.org/projects/project_rotator.html

About the spurious ‘!’ - I just put in some code to delete it if found and moved on - has been working since.