M1225 - TX Power Calibration across band

[g8tzl2004]

I have a VHF M1225 (150-175MHz) which should provide 40/25W high/low power. The radio works OK but I have the following problems :

- the maximum TX power level at different "in-band" freqs varies substantially (ie. 18W at 155MHz , 35W at 160MHz and 29W at 165MHz)
- the High/Low TX toggle key (using original settings) does not seem to have any effect on my power meter.

The original TX Power Calibration figures looked "sensible" for Low and High power ie.
LOW TX
0 (134) , 1 (136) , 2 (140) , 3 (143) , 4 (147) , 5(150) , 6 (153) and 7 (156)

HIGH TX
0 (169) , 1(174) , 2 (180) , 3 (185) , 4 (190) , 5 (195) , 6 (199) , and 7 (203)

I have tried increasing the HIGH "0" TX calibration value (169) but I never get more than the current 18W. I guess I should get 40W max. Likewise , the LOW "0" TX calibration value (134) still gives 18W although I should get 25W. . I have also used the "broad" calibration feature which aligns the set at 160MHz and proportionally resets all other levels - again , this has no effect on the max power at 155MHz.

However , I have managed to lower the LOW power setting to 5W by using the broad TX calibration feature - at 160MHz (level 3) , the TX calibration value needed to be reduced from 143 to 54 to give 5W.

Do the above TX power calibration levels for a VHF M1225 look correct? Maybe the calibration values are interdependant so I need to reset everthing to a "start" value?

Any thoughts?

Thanks