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      PRC-68
  PRC-68 B
      TS-3354/PRC-68

 

 

 

 

 

  PRC-68 B

is a "Squad-Radio", a radio operated with one hand for short range communication. Older well known examples for Squad radios are SCR-536/BC-611 (AM) from WWII or PRC-6 (FM).
The demand for a modern Squad Radio resulted in the development of the synthesized PRC-68, becoming the "father" of radios to follow: PRC-68A, PRC-68B, PRC-126, PRC-128, and PRC-136.
PRC-68B (and PRC-128) was an outgrowth of a tactical radio, but was used for Air Force missile site guard duty.

You may find a very detailed history of this radio in
"The AN/PRC-68 Legacy"
by Alan Tasker, WA1NYR.


The collection shows all American Squad Radios from their beginning (1941) to 1986.
 

MAB
(1941)

DAV
(1941)

SCR-511/ BC-745
(1941)

SCR-536/ BC-611
(1942)

RT-196/ PRC-6
(1950)

(PRC-34/ PRC-36)
(1961)

PRR-9/ PRT-4
(1965)

RT-1113/ PRC-68, A,B
(1976/84)

RT-1547/ PRC-126
(1986)


 
PRC-68 B was ordered by the Marines and the Airforce of the USA. It has the most functions of all radios of this family, including the following ones.
It comes with a lot of improvements:
 
  • It is controlled by a microcontroller (like the PRC 68 A).
     
    It has a
  • LCD- display (Placed where the PRC-68 had its loudspeaker/microfone, thus making the PRC-68 B 1.6 inches longer) This size and the display became a standart in all the following radios of this family.
     
  • It has a Cloning- function.
     
  • Two frequency bands can be chosen:
  • (Low band 30 .. 88 and high band 130 .. 174 MHz); The bands can be changed by swapping the RF/IF- module. The display in the low band is the operating frequency, the high band operation does not show the "1". Only showing "30 .. 88 " or "30 .. 74" may lead to confusion, so "Hi" or "LO" can be displayed, thus showing the RF/IF- module built in.
     
  • All channels of high and low band can be programmed in 2.5 kHz increments, making the radio compatible to all bandplans.
     
    Every channel may be programmed as
  • Narrow band FM, 3 kHz, ( used by HAM, Police, firemen etc ) or as
  • Broad band FM, 8 kHz, ( military use ). (All other radios of this family have broadband FM in the low band and narrow band FM in the high band).
     
  • To program the PRC-68 or the PRC-68 A you had to remove the housing, and dust, sand or water could get in. The programming switches of the PRC-68 B are behind a screw cup sealed by an o-ring, making programming much easier- the screw cap can be opened by use of a coin.
     
  • The previously separated switches of antenna tuning and R/T- filter are combined and the switch is now on the outside of the housing.
     
  • The number of switchable frequencies is enlarged from 4 to 5 in the low band, and a new "H"- position is added- which in fact is a 50-ohm-position.
     
  • When the antenna switch is in a wrong position, the microcontroller sounds a warning tone.
     
  • The audio plug was changed from a 5-pin plug at PRC-68 and PRC-68 A to a 6-pin plug. The extra plug is used for cloning and retrans functions.
     
  • Split frequencies, i.e. absolutely independent frequencies for transmitting and receiving can be programmed in the range of the RF/IF- module that is used.
     
    Quoted from the Article Alan Tasker :
    "U.S. Military Portable Radios"

    Frequency ranges:
    130 .. 173.9875 MHz or
    30 .. 87.9875 MHz

     


    Technical data:
    Channels:
    10
    Increment:
    2.5 kHz
    Channels:
    10000
    HF output:
    0.2 .. 2 W
    Mode:
    FM wide (8 kHz deviation) or FM narrow (3 kHz deviation)
    Frequency departure:
    +/- 0.005 %
    Frequency control:
    Microcontroller
    Display:
    LCD
    Range:
    3 ... 5 km
    Antenna:
    20 inch rubber duck AT-892
    Handset:
    H-250 (optional)
    Powered by:
    12 .. 16 V
    Squelch:
    150 Hz tone squelch transmitting, Signal squelch receiving.
    Sensitivity:
    0.5 µV / 10 dB
    NF- Output:
    20 mW
    Produced from:
    1984