R.A.F. Transmitter AT1154 and Receiver AR1155
The AT1154 transmitter and AR1155 receiver formed one of the most widely used radio communication systems in Royal Air Force bombers and transport aircraft during the Second World War. Manufactured by several British companies, including Marconi, these robust sets were installed in aircraft such as the Lancaster, Halifax, and Mosquito.
The AR1155 was a versatile receiver covering frequencies from 75 kHz to 18.5 MHz, allowing wireless operators to tune to ground stations, beacons, or shortwave broadcasts. Its design included direction-finding capability, enabling navigators to obtain bearings on radio signals — a critical aid when returning from deep-penetration missions in poor weather or damaged aircraft.
The AT1154 transmitter complemented the receiver, operating in the HF band between 2.5 MHz and 18 MHz and capable of both voice (AM) and Morse (CW) transmission. Its distinctive tuning dials and glowing valves became familiar sights in wartime wireless operator stations. Together, the pair provided reliable two-way communication between aircrews and ground control across the vast distances of Europe and beyond.
The reliability and adaptability of the AT1154/AR1155 system made it a cornerstone of RAF airborne communication, and many examples remained in service long after the war. Preserving and operating these sets today keeps alive the sound, skill, and precision that once linked bomber crews to their comrades on the ground.
Diagram shows Typical component and inter-unit Cabling.
Technical Details
Overview & purpose:
T1154 / AT1154 Transmitter
The T1154 (sometimes labelled AT1154) was a high-frequency aircraft transmitter used by the RAF during WWII in heavy bombers.
It was designed to pair with the R1155 receiver to provide two-way communication (voice AM and Morse CW) across long distances and often under difficult conditions.
Technical specifications, design & circuitry highlights:
Frequency coverage: approximately 2.5 MHz to 18 MHz (HF band) for transmission.
Power supply: The High Tension (HT) voltage required by the transmitter valves was over 1,200 V in many implementations. The set used a separate power supply unit — often a dynamotor or rotary converter (depending on aircraft installation) to generate the HT voltage from the aircraft’s 6 V, 12 V or 24 V supply.
Physical size & weight: The manual gives overall dimensions around 17 in. × 16 in. × 11 in, weight in the order of ~21 kg (or ~46 lb) for the transmitter in its case.
Circuit topology / major functional blocks: The transmitter uses high-power RF amplifier valves (tubes) and modulation circuits for voice (AM) and CW keying. The design must include output tuning (loading the antenna), plate circuits, HT supply switching, and often remote or aircraft-panel controls. (Exact circuit diagrams can be found in service manuals such as AP2548A (T1154-R1155).)
Construction details: Because the set had to work in aircraft (vibration, extremes of temperature, limited space), it had heavy-duty mounting, shielding, and cooling considerations. The HT “dynamotor” version implies the presence of mechanical conversion from low-voltage DC to high-voltage DC for the transmitter section.
Operator controls: Typical front-panel controls include frequency-band selector, tuning condenser/dial, power switch, modulation-level control, and often an external antenna-tuning/antenna-loading control. The accompanying manual provides operator instructions and alignment procedures.
R1155 / AR1155 Receiver
Overview & purpose:
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The R1155 (often abbreviated R.1155) was the companion receiver to the T1154 transmitter in many RAF aircraft.
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It covers a wide frequency range (LF/MF/HF) and has direction-finding (D/F) and homing capabilities—important in bomber navigation and safety missions.
Technical specifications, design & circuitry highlights:
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Frequency Coverage: 75 kHz up to ~18.5 MHz. One reference states coverage from 75 kHz to 18.5 MHz in five bands.
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Band divisions: For example, the set covers 75-1,500 kHz (LF/MF) in two bands, and 3-18.5 MHz (HF) in three bands.
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Sensitivity: Some specs give sensitivity better than 10 µV on all bands.
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Circuit topology: The R1155 is a superheterodyne receiver: It has an RF amplifier (pentode), mixer/oscillator (triode or pentode), two IF (intermediate frequency) amplifier stages, detector, BFO (for CW), audio amplifier, plus a magic-eye tuning indicator. In D/F mode the set includes auxiliary valves for loop switching and bearing meter circuits.
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Direction-Finding (D/F) capability: The receiver incorporates circuitry and external aerial switching for loop aerials, trailing wire aerials, and fixed wire types; the operator can switch to D/F aerial, read bearing on meter, and return to normal listening mode.
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Valves (tubes): Typical R1155 includes about 10 valves: 6 for main superhet receiver, 3 for D/F and aerial switching, and one magic-eye tuning indicator.
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Controls & front panel: Band selector switches, tuning dial with calibrated frequency, BFO switch for CW/Morse, mode switch (AM / CW / D/F), volume, tone, D/F loop control (when in D/F mode). There may also be sockets for external aerials or earphones.
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Construction: Built for aircraft service—rugged chassis, labelled for aerial configurations, shock-mount fittings, panel handles, portable size for aircraft fit including accessibility for the Wireless Operator. Example: one museum unit is described as “Receiver Type R1155, No. 32491 … black metal … semi-circular frequency dial, 3 knobs, 2 chrome handles.