The pages on this 220 conversion site are copied from a site I did so long ago that the camera I use stored to a 3.5 inch disk. It not an update, just trying to preserve the information and typos.

N4KHQ Bench

GE Mastr II 150.8-174MHz Conversion to 220MHZ

This modification was designed by Dave Ackley W4UWH and will require from 8 to 16 hours of work to completely modify a GE Master II 150.8-174 MHz into a 220 MHz repeater. The PA presents the most challenge and Dave has made the modification by changing one of the power transistors and several capacitors but Dave has a $16,000 IFR Service Monitor and knows how to use the equipment. I am convinced the modification is beyond all but the most knowledge RF specialists. I tried a couple of PA mods I found on the www and none performed well enough to be used for a repeater. After spending $60 for rf power transistors and capacitors, one modification produced 7 watts and the other produced about 40 watts but had a half frequency spurious signal. The solution Dave suggested for me was a $59 RF Parts # M57774 Power Module. I use the web page as my notes. I have updated the Exciter Modification page with directions as to how to tune a modified exciter and added the PTT Fan/ARR protection link