I hope this is the right forum. This is in regards to the AN/PRC-90-2 emergency radio used by the military during Vietnam. My questions are what was the wattage of this radio and what does Voice MCW mean?
It has been a number of years since I had my hands on one (more than 30), but lets see if I can answer the MCW question. The power question has already been addressed.
As someone else said, MCW is Modulated CW. This is a way of sending CW (Morse Code) so that aircraft receivers (which are AM) can hear it. If you sent “normal” CW (ICW) then AM type aircraft receivers would not hear the tones. So MCW sends a normal AM transmission (full DSB plus carrier), but uses an audio tone to make the Morse tone sounds, often in the neighborhood of 1 kHz audio tones. Of course you have to have a way to “key” the MCW.
The radio has a roller switch on the right side. Turning it “up” from the OFF position places the radio in VOICE mode and on the freq of 282.2 MHz. You then use the Push to Talk (PTT) button (also right side, above the mode roller switch) to key the radio and speak into the microphone.
Rolling the roller switch “down” from the off position puts the radio in the VOICE/MCW mode and on 243.0 MHz. You can still use the PTT button and speak into the microphone with normal voice. But what if for some reason you cannot speak? Then you can send Morse Code, in the form of MCW. To send MCW you press the button on the top of the radio instead of the PTT button. This top button is your Morse Code key.
Rolling the roller switch one more position down places the radio in the BEACON mode and on 243.0 MHz. If I remember right it transmits continuously in this mode. One version might have had the ability to go to a high power beacon mode by pressing the MCW button on top while in the BEACON mode, but I am not sure about that.
T!