[MRCA] Helmet radio

[Mike Morrow]

The VHF-FM set that was enclosed within a (from the set manual) "plastic, combat type helmet" is the AN/PRC-34(X1).  It has a steel-wire whip antenna in front that is normally swept backward.  It uses 15 transistors and one vacuum tube.  Frequency range is one channel beteen 38.0 to 51.0 MHz.  Rated power output is 30 mW.  It requires a unique dry battery to provide -4.5, +1.5, and +50 vdc.  It has no squelch of any type.

The RT-unit uses 2N105, 2N128, 2N269, 2N299, TAE1649 Germanium transistors and CK6051 vacuum tube.  Pretty early stuff.

The same RT unit in a combat belt-mounted package and a band with antenna and earphone fitted over a standard combat helmet is the AN/PRC-36(X1).

These sets were made by RCA for U.S. Army Signal Research and Development Laboratories.  My manual for these sets is dated 13 January 1961, but the sets appeared first a couple of years earlier.

I got one of each through US NAVMARCOR MARS in 1969.  It was easy to put together a battery back then when 22.5 vdc batteries were still common.  That's needed only for transmitter B+.  The receiver circuits need only the two other voltages.  I still have them.  Interesting sets!

There have been a lot of incomplete AN/PRC-36(X1) units sold on ebay in the past few years.  They do NOT have the RT unit and are therefore very useless.

Mike / KK5F

-----Original Message-----

From: DSP3 

    Exclusive of the PRR/PRT radio sets, does anyone
      recall the radio or the nomenclature of a radio set that was
      molded into the battle helmet?  It had a little whip that stuck
      out.  The radio was sort of potted in Styrofoam or something? 
      MARS had a few of them come through back in the 60's.  Just a shot
      in the dark as the question came up in a ARNG forum today.

      Jeep - K3HVG