Ok. So the syncing does not work by some magical reason.

I would like to ask to test some things without clear sky:
1. Start your system.
2. Sync your handset inside KStars _without plate solving_. In KStars, go to a sky position, open a context menu, inside Synscan submenu, there is the Sync option. Select it and verify if the Synscan points to the new synced location.
3. Try the previous step in different parts of the sky.

Let us know if this kinda manual syncing works well or if it is does not work for some kind a RA or DEC coordinates. I am pretty sure now what is the problem, my current bet is that syncing does not work with negative RA and DEC values, but it works fine with positive RA/DEC values. My location and sky visibility does not have negative RA/DEC values therefore they were not tested. Let me know if my guess is right!

I tried to follow your suggestion.
Unfortunately, the manual synchronization directly from the map of Kstars results unsuccessful for all the coordinates I tried: both positive or negative AR or DEC coordinates. For all the attempts I tried I always obtained that the crosshairs of the Synscan are far away from the coordinates I want to synchronize..
It's very very weird...

In the attached image I report you my attempt to synchronize the mount with the coordinates of Sirius ...

Any news to solve this issue?
To date I have not fixed this problem.

I don't have Synscan cable right now because I killed the previous one. The only thing you can do to record a log of the Synscan driver and attach here to have a look. At least I don't have any other idea how to progress further. You can change the logging levels before you connect to the INDI server in Ekos. There is a "Log" button where you can make verbose the logging. Then do a minimal test case with manual syncing on the sky map, stop the INDI and upload the log here.

Had a quick look at the code. In the Sync function, it looks like you're converting the RA/Dec into Alt/Az. In reading the Synscan Serial Communication Protocol PDF, it looks to me like they want RA/Dec for EQ mounts, or Alt/Az for Alt/Az mounts, whereas you're always converting to Alt/Az. That could be the source of the problem.

I don't have my mount setup right now, or I'd make the change and test it out. I won't have it set up until Sunday at the soonest.

-- Kevin

Ok thanks kecsap. I will try this procedure as soon as possible.

Thank you for your interest Kevin!
Actually this could explain my problem. Unfortunately I have no idea how to change any part of the software, so the only thing I can do is to wait for your assistance.
The only thing I wonder is how it is possible that this problem occurred only to me.. I mean, if it is a problem of coordinate conversion from AR/DEC to Az-Alt, my problem should be common to every user of stars-ekos that has an equatorial mount...
Anyway, I hope that your inference is the solution to my problem!
Thank you again! I'll wait for your checks!

A.

Well I think that most people use EQMod instead of Synscan driver. I'm one of the few weird ones that use Synscan instead. I haven't run into the problem myself because I haven't tried using the solver.

I tried to do what you suggested me. I hope it is correct.
I attach the log file in this post. Thanks!

I played with this some over the weekend. I changed the code so it sends RA/Dec instead of Alt/Az. The Dec axis gets updated just fine, but the RA axis wouldn't update. Not sure what's going on. I will have to mess with it some more.

Brilliant!!
This sounds considerably good! Thanks for your efforts. I'm curious to see the final result and to finally use the SynScan also with ekos.
I look forward to hearing from you!
Bye!

By the way, I hope you guys can keep this driver compatible with the V3 hand controller because I discovered that older HEQ5 mounts cannot upgrade to the V4 version. Thank you for your work on this!