Hi I was testing mine, and had a lot of spurious, when the power was 5 watts, all of a sudden the power dropped to 2 watts ( I am in FT8 mode) and used the tune button to check power. I initially set up using 3:2 and 12V, so changed to 3:3 and 9 Volts, I still get the same power. Current drawn is 320mA. So not sure why I have lost power. I am not familiar with the WSJT software, and have not been able to make sense of the frequency cal process, I do have a 10MHz GPS rubidium oscillator, so do not need to the off-air transmissions.
M.W. Transmitters can not be relied on for frequency accuracy, some are free running, (I know as I maintain them.)
I have enclosed a plot of IC5C pin 3 and 8, this may help:
73
Andrew
Andrew Lenton