Administator with password "smate." - Never put your password on a public web site - hopefully you changed it straight away and its not used anywhere else
RPI3b+ - As far as I am aware ,after my last test , 5ghz Wifi still does not work - 2.4ghz Wifi works fine.
But as already pointed out this version (Ubuntu Mate 18.04 workstation release ) is a "beta" release so not the finished article. 18.04 file server version has been working for over 1 yr.
IMHO it is not advisable to run the official Ubuntu Mate 18.04 Workstation version on a RPI3b+ if you want a stable Ekos/Kstars platform - the latter Indi Software not being the problem as far as I am aware as it runs fine on other hardware platforms using 18.04.
Perhaps the Indi developers would clarify the situation with RPI3b+ ,18.04.02 Workstation and Kstars/Ekos
You can of course buy a USB splitter cable which enables direct powering of a USB device while still providing data signals - AND doesn't lower the USB bandwidth which an external USB hub does - ok maybe on USB3 depending on how speed hungry the device(s) are.
The only problem is there arn't many outlets that sell such cables but you can build your own
Another help - try changing the down sample to a higher figure say 8 and see how many stars are extracted - I aim for 350 which ,on a RPI, works as the poor thing doesn't do maths very fast (better than me !). You may have to play with this figure as different nights/position/seeing all effect the number of stars extracted and therefore Platesolving IMO.
This all assumes you have the correct Index's and FOV set correctly plus dont download all indexes as this will slow things down as well.
Indi does really need a simple mod (LOL) to allow for every index file but rename the ones actually needed for the FOV as many will use different scopes and camera's on the same rigs. Someone will now say it does this already - LOL
Just in case there is a problem with either mouse or keyboard (yes I know there shouldn't be) unplug them and use SSH or Remote VNC via wireless - just a thought !
Enjoy your flying.
Th eonly other options I can think of are :-
1. If you have a spare RPI - connect 2 x Indiserver chained one with Mount and the other with Filter wheel see if the problem still exists.
2. Again if you have a spare RPI (even a zero(w) will work) and if you know ser2net (will need to be installed) run the Mount on the "Spare" and configure Ser2net (again on the Spare) to pass thru Ethernet IP and port to USB0 . Set the Mount Ethernet as the connection type on the Indi Device to the IP/Port of the spare. Connect the Adapter to the Mount and then the USB port on the "Spare".
Ser2net has got some decent logging if my memory serves me but you can also "T" the data .
Not sure if either will find the problem .
Cant remember ,think the answer is no , can you adjust any read time out parameters for one or both of the ports in Indi Devices to allow longer delays ?
RPI may not be fast but I have DSLR,Mount,GPS adapter, DIY Moonlite focuser(Arduino) all plugged in (no USB HUB used) and haven't noticed any errors but I just use 5GHZ Wifi. Days are gone when you needed hand shaking via DTR/DSR etc.
Maybe a software issue with the drivers - have you another mount - say SW - that could replace the Celestron - as a test. I know Moonlite protocol is "chatty" but its hardly likely to overload the USB BUS.
Nothing odd in RPI LOGS ?
The only time I had a problem ,as you describe ,was when I was using Prolific adapters or cheap "non genuine" FDTI adapters especially with "long" (1m plus) cables.
Perhaps you should try a powered hub and see if the problem goes away.
And of course poor cables/connectors.
On the RPI3b+ I use one of these and have no problems - just use an appropriate fuse. Plus I dont mix sensitive electronics on the same converter.
Plus I be a lot of people dont even see the message as remote access doesn't show the error - unless they check the logs.
Unless I am going mad(quite poss) - 5ghz now connects ok but ns lookup still fails - works on wired and 2.4 fine.
Perhaps by the time its released it will be sorted
Plus it appears to me to me very slow compared to the old 32bit 16.04 but that could be just my imagination - no facts
Perhaps mate 18.04 is a step too far with a desktop for RPI3B+ ?
Couple of things
1. Its still a Beta release so expect some problems.
2. WiFi 5g fail to connect if you connect firstly by Wired for installation and upgrade then try to connect to Wifi - But 2.4g works fine-odd that.
Problem lies with auto set up attaching itself to device address instead of Wlan(0) so you have to make sure it is attached to the correct hardware - wlan(0) which is in the drop down menu under "Device" under Nework connections. This worked for me.
I Quote someone from Sky At Night who says - "Technically they haven’t imaged the black hole as it is a singularity, what they’ve done is clearly image the event horizon just as material is super heated then falls in and disappears"
Sorry for sticking my nose in again but I think you are missing the obvious - the comms link is working ok else you wouldn't be getting the output from EQMOD as I beleive the Serial code for the Open command is the same. Its the handshaking protocol (as KNRO is hinting at I think) that's failing (sorry if I am wrong) for the Synscan legacy code. Have you tried the AZGTI driver (non wedge) ?
If you Logic Analyser I would have thought thats a voltage problem - as I stated earlier the AZSWGOTO wont work with 3.3v has to be 5v - unlike my AZEQ6 which is ok wih 3.3 and 5v.
I have used the FDTI USB with success never a problem (so long as its the correct voltage version) - the Prolific works but is very "iffy" weak signals ? - suppose thats why its cheap.
If you can please try your cable set up in a Windows Environment using Synscan App Pro and see if that is able to control the mount. Unfortunately the last time I looked there is no Python API for Indi for Windows (might be wrong again) but I believe you can use SWIG to convert the C code but KNRO would know if thats true. As I said , and this was true for an Arduino WiFi ESP32 project I did, SWAZ GoTo doesn't like being started up first . Any how just a thought !
I will get back under my rock now