I tested 12 HC-12 on my regular Nanos using software serial and none of them worked, though they worked with USB-TTL converter. So I knew the problem wasn't with the HC-12 but with the Software Serial library having read about issues with the stop bit not being wide enough. Okay, SS is off the table. I purchased two official Nano Every and using the same USB cable, protoboard, pins and wire jumpers I used for the regular NANO: INSTANT KARMA. Type AT, get OK. Of course I'm using the HARDWARE serial ports (D0,D1) of the Every which is key. So, guys, gals, SAVE YOURSELF THE AGGRAVATION, get the Every if you are a NANO fan, and forget about Software Serial. None of my old projects (3 robots) could communicate anymore so I'll be rewiring them with Nano Every.
If the stop bit length is the only issue, that should be easy to fix! (Do you have a reference for that issue?)
That said, you ARE better off with a hardware serial port, plus the other extras on the Every.
At what baud rate? 9600 ?
9600 baud. I also tried other baud rates and power levels, and channels. Couldn't get an OK.
6v6GT...isn't that an old vacuum tube? (Shows how old I am...)