Code: cat /sys/class/i2c-adapter/i2c-2/2-0063/power_level 88 here. I tried setting it to 118 while transmitting and what a difference! Suddenly so much clearer. I did find that file /sys/class/i2c-adapter/i2c-2/2-0063/power_level did exist when FM transmitter was off. I also found that plugging in a wall charger dropped the power level to 88. Now to make it persistent...
cat /sys/class/i2c-adapter/i2c-2/2-0063/power_level
[Desktop Entry] Encoding=UTF-8 Version=0.1 Type=Application Terminal=true Name=POW Exec=sudo gainroot Exec=echo 118 > /sys/class/i2c-adapter/i2c-2/2-0063/power_level Icon= #X-Window-Icon=timerwidget X-Window-Icon= X-HildonDesk-ShowInToolbar=true X-Osso-Type=application/x-executable