What was the wattage for the AN/PRC-90-2?

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poltergeisty

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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?









Thanks!
 

lep

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MCW = modulated cw. For acting as a beacon. 500 mw.

These sell on ebay for less than $200 mostly as a military collectable of the Vietnam war era.
 

poltergeisty

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Thanks for your promp response. Yeah, seen this unit on eBay and I was laughing because they say microwave. Probably in replace of MCW. :lol:

So 500 mW is the total wattage of this unit even for voice?

I thought I read somewhere that the military has a sat that can locate one of these units. Is that true? :lol:

Oh ya! What type of battery do they use?
 
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lep

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No for voice it is 400 mw. It used 4 CR 123 batteries. Since it transmits on 243 MHz the aircraft distress frequency, when in beacon mode it could be located by a sat.

Google is your friend, you can no doubt find out more than you would ever want to know on some of the military collector sites.
 

mancow

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Isn't that the same type the lead character used in the movie BAT21?

Modern version:

 

lep

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"24 June 2002 - New 90BAv2 Battery Adapter has 1.3 AH capacity and can be used operationally.
There also may be a government official adapter that holds four each 123 photo batteries. ":

Here is a copy of a paragraph in the link quoted above, notice the reference to #123 batteries.
The most important fact is the capacity and voltage. Of course making it come-on-the-air is risky since it transmits on the known aviation distress frequency and you don't want to get rescue in the act. It is just a novelty as a collectable. The PRC-90 was 1960-1970 Vietnam era, the whole unit has now been replaced with more modern stuff. I was an Army Signal Officer in this time frame and the PRC-90 was the latest stuff! But that was the old days. Yes, the movie was a good one and it is based on the book and is a true story making some allowances for Hollywood.
 

prcguy

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The 90BAv2 is an aftermarket adapter from Brook Clark who makes lots of other adapters for surplus military radios.
prcguy

"24 June 2002 - New 90BAv2 Battery Adapter has 1.3 AH capacity and can be used operationally.
There also may be a government official adapter that holds four each 123 photo batteries. ":

Here is a copy of a paragraph in the link quoted above, notice the reference to #123 batteries.
The most important fact is the capacity and voltage. Of course making it come-on-the-air is risky since it transmits on the known aviation distress frequency and you don't want to get rescue in the act. It is just a novelty as a collectable. The PRC-90 was 1960-1970 Vietnam era, the whole unit has now been replaced with more modern stuff. I was an Army Signal Officer in this time frame and the PRC-90 was the latest stuff! But that was the old days. Yes, the movie was a good one and it is based on the book and is a true story making some allowances for Hollywood.
 

Token

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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!
 

BMT

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I heard the BEEPER on 243.0 while in VietNam.
A sound that would make the hair on your neck stand up!!

BMT
 

autovon

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The PRC-90 was still being used in USAF stateside survival kits in the late 2000s. The Hook 112 is a cool little radio with some nice capabilities.
 

Fast1eddie

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I was screwing around in the Avionics shop one day back at Fort Rucker and we had several come in for PM's. Never mind I was smack dab in the middle of Cairns Army Airfied, helos and fixed wing everywhere-active airfield, lots of birds in the air. Activated the beacon, talk about it hitting the fan!!! Got one butt chewing on top of another that day, never believed low power RF would get out.

It did.

Lesson well learned.

Good Signals,

ed
 
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