A BIG "THANK YOU" TO MIKE FOR MAKING OUR HOBBY BETTER AND BETTER..
Here is a little tutorial with pictures


It explains how to connect and configure the Bluetooth modules as well as how to increase the range a little for more reliability..
Please note that the pictures show MY module and some other modules might be different. Also, you might want to do things differently. Do this mod at your own risk. Be very careful with polarity and not to short anything as it could release some of the magic smoke electronic parts have inside them

Please feel free to share your own installation. I would also like to read some opinions about whether or not the Bluetooth RF signal (which operates on the same frequency as our main RF modules) could have negative effects on the main RF system, even if both antennas are at right angles to each other.. So, comments on this are very welcome.. Of course, testing will follow as soon as the weather allows

AT THE MOMENT THIS IS ONLY SUPPORTED BY ERSKY9X
ATTENTION, YOU MUST INSTALL THE LATEST ERSKY9X TEST VERSION FOR NOW AS THIS FEATURE WAS NOT RELEASED YET..
Please get it here.
viewtopic.php?f=7&t=4676
The pictures show a HC-05 bluetooth module that you can buy cheap on ebay. If you can, I think you should go with the HC-05 as it can be configured as MASTER or SLAVE.
No need to say, that you will need two radios with a BT module and Ersky9x installed

I'm not referring to any radio in particular because as far as I know it can be installed in all platforms that run Ersky9x, except probably the Taranis radio. Not sure. Mike, please correct me if I'm wrong here

Ersky9x expects the BT module connected to COM3 for the trainer setup.
So lets start with the BT connections:
Now, how to configure your radio for Trainer over Bluetooth:
Model Setup/Bluetooth menu:
This video also explains how to configure the Trainer over BT:
https://www.youtube.com/watch?v=c3EGm-IZghI
Also when configuring the Trainer in "Radio Setup/Trainer, there is now an option to select the Trainer source. When using Bluetooth as trainer please select "BT" on both radios. This stops the radio looking for PPM on the input Jack.
How to modify the BT module to increase the RF range:
I had the Bluetooth modules installed inside the radio. the problem is that the signal from these modules is already quite weak, and when inside the radio there are lots of things blocking the signal.. Battery, wires, our hands, etc. This leads to a very short range.. I did try flying it like that while teaching my son, and it worked. But he had to stay next to me. I tested at home and I was getting only a couple of meters of reliable signal. it will work if both radios are close to each other but it is not ideal..
So, Mike sent me a link where someone had soldered a wire to the BT module replacing the original antenna. Hmmm, i didn't really like the idea as in my opinion it would be quite easy to knock the antenna and destroy the module.. So, I thought I could use some flysky and frsky antennas I had here at home.. Well, the flysky antennas had the wrong size (25mm, I wonder why the range is not that great with the flysky modules

Secure the antenna to the board with some hot glue..
I hope this tutorial is easy to follow. Enjoy it..
A zip file with all pictures is attached to this post..
João