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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.
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 aLCD- 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
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PRC-68
TS-3354/PRC-68