PM1 has VFO control of receive and transmit for 80 and 40 meters and crystal controlled transmit on 15 meters. PM1 has 4 circuit boards, MX1 mixer, TX1 transmitter, AA1 audio amp and VO1 variable oscillator. Basic PM 1 had no sidetone and manual TR switch. AC6 optional board added VFO controlled 20 meter transmit and receive and sidetone. AC3 board added VFO controlled 15 meter transmit and receive. PM1 had one empty slot for the AC3 or AC6.
Appearance: PM1 had no top or side covers, only the U shaped sheet metal chassis and had PM1 on the lower right side of the front panel.
There are 2 versions of the PM 2:
Version 1: Side panels and a top were added to the basic PM1 to make a PM2. This version of the PM2 has 4 boards and could be fitted with an AC3 or AC6 optional board. This version of the PM2 has PM1 on the lower right side of the front panel.
Version 2: Version 2 has one large circuit board and VFO control of transmit and receive on 80 and 40 meters and crystal controlled transmit on 15 meters. No optional boards were available and no sidetone.
PM 2A is the same as PM2 version 2 with sidetone.
PM 2B also has one large board with VFO control of transmit and receive on 80, 40 and 20 meters, no sidetone.
PM1 and all versions of PM2 have 2 watts RF input.
PM3 has four circuit boards with VFO control of receive and transmit on 80 and 40 meters.
PM3A is the same as PM3 with the addition of the AC7 board for semi QSK break in keying.
PM3 and 3A have 5 watts RF input and sidetone.