Type: 2 set transceiver: 'A' set: HF, 'B' set: VHF. Also intercom amp for tank crews.

Frequency range: A-set: Mk.I: 2.5 - 6.25MHz Mk.II & III: 2 - 8 MHz. B-set: 229 - 241MHz

Modes: A-set: AM R/T, MCW, CW. B-set: AM R/T.

Tx output: A-set: R/T 1-3W; CW 3-5W. B-set: 0.4W.

Aerials: A-set: vertical 8 - 16' rods; long wires. B-set used a (/2 rod, fed by coax cable an integral number of half-wavelengths long.

Power supply: 12V DC, 4 to 11A depending on Mk and mode. From lead-acid battery, charged by separate generator or vehicle generator.

Further info: Wireless for the Warrior Vol.2.

Major components: set containing A-set, B-set (if fitted) and IC amp, power supply unit, variometer for aerial tuning, c ontrol unit for connecting headset/mic, carrier.

Circuitry: The A-set uses 9 valves. The Rx is a standard single conversion superhet, with a 455KHz IF. The Tx uses a mixer system based on the Rx LO to ensure Tx and Rx are on the same frequency. The PA uses a control grid-modulated 807. The B-set has 4 valves. The RF valve is an oscillator on Tx, and a super-regen detector on Rx, with a separate quench oscillator.

Variants: Lots! Apart from the three Mk. nos, some sets had the B-set removed during 1950s reconditioning, and there is a major Canadian variant, which has front panel markings in both English and Russian, as well as rarer ones from elsewhere. The Amplifier RF No.2, using 2/4 807s in parallel, turned the set into a WS19HP, which gave it a welcome range boost, with about 10-14W output on R/T. There are about 15 different control units, and many variants of these too.

Usage: introduced in 1941, and used widely by the Allies in WWII, and afterwards for many years. Typically mounted in tanks, other AFVs, jeeps, etc, but also used as ground stations, and in aircraft.

Notes: This is the classic military HF Tx/Rx, used by generations of amateurs after WWII. This is more due to samples being available in vast numbers at relatively low prices, rather than any great technical merit. It is still fairly common, though much beloved by the military vehicle fraternity. Watch out for examples butchered by previous owners!

I used several "brand new" sets in the early 70s, on the Cadet Force nets operating on 5330KHz. Despite low power, poor modulation, etc, they worked extremely well, offering reliable coverage from the UK south coast to Yorkshire on a simple dipole - some 300 miles!