THE PRE COMMON VALVE NUMBERING SYSTEM USED BY THE BRITISH ARMED FORCES

Having broken off from my historical diatribe on Mullard, here are a few useful snippets about the pre CV valve numbering system used by the British Armed Forces - here is an explanation of what the various alpha suffix codings used by the different service arms mean - now you'll at least be able to identify the valve type if not the type number:-

British Army

Comprises of an alpha coding which signifies the valve use or configuration followed by a numeric code that signifies valve.  The most commonly seen are listed below:-

ACR - Army  cathode ray tube
AR - Army receiving valve 
ARD - Army receiving diode
ARDD - Army receiving double diode
ARH - Army receiving hexode
ARP - Army receiving pentode
ARS - Army receiving screen grid tetrode 
ARTH - Army receiving triode hexode
ARTP - Army receiving triode pentode
AT - Army transmitting valve 
ATP - Army transmitting Pentode
ATS - Army transmitting screen grid tetrode
AU - Army Rectifier
AW - Army Stabiliser

British Royal Air Force

Comprises of an alpha coding which signifies the valve use or configuration followed by a numeric code that signifies valve.  The most commonly seen are listed below:-

VCR - Valve cathode ray tube
VGT - Valve gas thyratron
VI - Valve indicating magic eye
VR - Valve receiving 
VS - Valve stabilizing neon type
VT - Valve transmitting 
VU – Valve rectifying

British Royal Navy

Comprises of an alpha coding which signifies the valve use or configuration followed by a numeric code that signifies valve.  The most commonly seen are listed below:-

NC - Navy cathode ray tube
NGT - Navy gas thyratron
NR - Navy receiving valve
NS - Navy stabilizing neon type
NT - Navy transmitting valve
NU - Navy rectifier