Power: +23dBm seems erroneous, +20dBm is special

[danak6jq]

The SX1276 datasheet warns that max duty cycle at +20dBm is 1% - suggest running max of +17dBm from the chip itself. I also note that the radiohead library seems to offer +23dBm which is not a documented power level from the SX1276 (or the RF95/RF98 re-badged parts).

Cheers, Dana K6JQ