====== Manpack radios AN/PRC-8 - 10 ======
Produced by different U.S. manufacturers.

As a successor to the famous first "walkie talkie" [[BC-611]] and the "NATO banana" [[AN/PRC-6]], the American manpack radio AN/PRC-8 - 10 was also introduced to the newly formed German armed forces in 1956.

Three different versions of the transceiver operating with subminiature tubes were developed for three frequency ranges.

===== Technical data =====
  * [[Principle]]: [[transceiver]], [[IF]] 4300 kHz
  * [[Operation modes]]: [[F3|FM (F3)]]
  * [[Frequency range]]: SW resp. [[VHF]] 20 - 20.7 MHz
  * [[Frequency display]]: Analogue dial
  * [[Frequency memory]]: none
  * [[Signal strength indicator]]:
  * [[Transmit power]]: 1 W 
  * [[Features]]: 
  * [[Sensitivity]]: [[A3|AM (A3)]] / [[Selectivity]]: kHz (-6/-60 dB)

==== Power supply ====
  * [[Batteries]]: Combined battery BA-279 with four voltages, heater voltage 1.5 V, transmitter final tube heater 6 V, plate voltages 67.5 and 135 V.

==== Dimensions ====
  * 265 x 77 x 470 mm, weight 8.4 kg (with antennas and battery 11.8 kg)

==== Accessories ====
  * Handset H-33*/PT
  * Battery Case CY-744 for the BA-279 combi-battery
  * Carrying straps ST-120
  * Antennas AT-272 (steel band antenna, approx. 1 m) or AT-271 ()
  * Accessory bag CW-21

----

===== Operation =====
The AN/PRC-8 - 10 backpack radio was manufactured in three different versions:
|[[PRC-8]]|RT-174|20.0 - 27.9 MHz (80 channels)|Mechanised troops|
|[[PRC-9]]|RT-175|28.0 - 38.9 MHz (120 channels)|Artillery|
|[[PRC-10]]|RT-176|38.0 - 54.9 MHz (170 channels)|Infantry|

The battery box with the combined heater/plate battery is attached to the bottom of the receiver; one battery lasts for at least 20 hours. A vertical rod antenna AT-271 with a height of 3 m is available instead of the steel band antenna AT-272. The RC-292 ground plane can be connected to a BNC connector to be used as a long distance antenna; the radiating antenna and counterweights are made up of four to six elements depending on the frequency range; the antenna reaches a height of 12.5 m; with the ground plane antenna, the effective range is 19 km.

In the receiver part, the signal from the antenna first passes through two RF amplifier stages ([[de:1AD4]],[[de:5678]]) and is converted to the intermediate frequency of 4.3 MHz in the mixer stage ([[de:5678]]) with the signal from the free-running oscillator ([[de:1AD4]]). Four IF amplifier stages (four [[de:5678]]) are followed by the limiter stage ([[de:5678]]). The FM discriminator is made from two semiconductor diodes, the demodulated signal is fed to the AF amplifier ([[de:5672]]).
The receiver can be calibrated with a 1 MHz calibration oscillator ([[de:5676]]), and a 4.3 MHz oscillator ([[de:5678]]) is connected to the IF output at the same time. The receiver is tuned to zero beat and the line of the frequency dial is mechanically adjusted to this scale position. A squelch ([[de:5678]]) blocks the receiver output if no RF signal is present.

On the transmitter side, the transmitter oscillator (working as a Hartley oscillator, [[de:5A6]]) oscillates at the transmitter frequency; it is modulated directly by the AF signal of the microphone preamplifier ([[de:5676]]). The transmit frequency is determined by the (calibrated) receiver frequency, the transmitter frequency is adjusted to the setpoint by the automatic frequency control (AFR, tube [[de:5672]]) at the output of the crystal-controlled mixer stage.

===== Technical principle =====


==== Components ====
The set is equipped with miniature tubes.

===== Technical documentation =====

==== Development ====
{{gallery>:images?mil-usa-prc8*.jpg&0&80x80&lightbox&showtitle&titlesort}}
==== Further information ====
* [[https://www.radiomuseum.org/r/military_prc_8_rt_174.html|AN/PRC-8 on the website of www.radiomuseum.org]]