[TheOtherCliff]

do I have to select MAVLink or ComBridge in the hardware config? --

No.

Of course both sides must be configured with the same data rate and some other things must match / be set correctly too (e.g. min/max channel, data+control, coord/receiver) .

There is known bad RF hardware out there.  Put the two devices close together and see if it stops disconnecting, then watch the received signal.  With bad hardware you will see the signal level drop a lot once in a while.  When it is farther away that is when you get disconnects.  If you have 2 bad ones they talk together OK.  If you have 2 good ones they talk together OK.  A bad one and a good one do not work together.

There seems to be a way to tell them apart.  Read this post and then refer back to the first post to see the picture for the large and small X2 on the RFM22B (the RF daughter board on OpLinks and Revos).  Also for a video that shows the RF Level drop.
https://forum.librepilot.org/index.php?topic=4197.msg28517#msg28517

[gnumarco]

I have tested a bit more today. From the info you posted and from what I read in the link, I have a "good" Oplink, and my revo is not a clone, BUT today, my OPLink was not even able to start. When I plugged it in usb to my computer, the only counter that was increasing is the "reset" counter. It was never able to establish a link, just reseting in a loop.
This makes me think that my OPLink may have a hardware problem...what do you think?

[TheOtherCliff]

If all your versions (OpLink, Revo, GCS) match then I would guess that either you have bad hardware somewhere (sounds like OpLink) or your USB power is bad.

Try a different computer tor the different USB.  Measure the USB power if you can.  Reboot the computer?  Try a different cable.  Look for problems (cracks scratches, shorts) on the OpLink board.  Reflash the OpLink by unplugging it, go to Firmware, press Rescue, then plug it in, then flash however ... (UpdateAndErase or (Open)/Flash)).

Did you get the Revo from OpenPilot back in the day?  You can check the RF board on it too, but a real Revo should be OK.

[gnumarco]

Hi. I come back to the topic, as I have bought a new OPLink mini, and tried with it: same problem.
Here is what I did:

• Flashed the firmware to the OPLink mini (Upgrade and Erase)
• Configured the receiver

I have exactly the same behavior: it resets all the time (reset counter just incrementing...nothing else). See attachment.

Any idea?

I get my OPLink from this webpage: https://rc-innovations.es/OPlink-telemetria-cc3d?search=oplink&description=true

[f5soh]

Can you post the other side (means Revo) configuration ?

[TheOtherCliff]

You have to set OpLink to OPLinkCoordinator.  Most of the time the OpLink should be set to OPLinkCoordinator and the Revo should be set to OPLinkReceiver.

Also LinkType, AirDataRate, and FrequencySettings(all) must match.  Revo must match OpLink.

[gnumarco]

Here is the Revo config (attachment).
So, the REVO is RECEIVER and the GCS OPLINK is COORDINATOR?

Intuitively i thought it should be the other way around.

I'll try.

[gnumarco]

SOLVED.
Indeed, configuring the other way around, that is to say the Revo in receiver and the OPLink in coordinator, it works.
With airspeed at 100000, I still had sometimes a bit of lag, but I tried to go to 256000 and it work very well without any lag.