Hi, when did you start this new Transmitter?
2nd January 2020?
I have the feeling that Dexcom monitor all the forums and adjust their design to combat the latest methods of extending their sensors.
After all, they have very good reason to, as it is costing them money.
They obviously skipped the “8i” designation as it was too much like “81”.
I hope you find a reliable way of extending your 8J transmitter. If you do, please come back here and post a message to let us know. This message thread has grown a life of its own, and lasted much longer than I imagined it would.
Good Luck