RAF Transmitter T1154



There were 13 production versions of the T1154, being the T1154, T1154A, T1154B, T1154C, T1154D, T1154E, T1154H, T1154K, T1154F, T1154K, T1154L, T1154M, T1154N. The major differences are the CW and MCW (no R/T) only versions T1154A and E, the chassis and case construction material and the different frequency ranges between the versions (see below).

Purpose of equipment:

Airborne MF / HF transmitters used with receivers of the R1155 group, except the T1154D and T1154E, which are used with R1188 in mobile ground stations. The T1154N variant was used in RAF high speed launches (see here).

Frequency ranges:

T1154, T1154A, T1154B, T1154J, T1154N: 200 - 500 kHz, 3.0 - 10 MHz in 3 ranges.
T1154C, T1154F, T1154H, T1154K, T1154M: 200 - 500 kHz, 2.35 - 16.7 Mhz in 4 ranges.
T1154D, T1154E: 200 - 500 kHz, 2.5 - 8.0 MHz in 3 ranges.
T1154L: 200 - 500 kHz, 1.5 - 5.5 MHz in 3 ranges.

Frequency control:

Master oscillator control.


70 per cent, suppressor grid modulation on both MCW and R/T.


Carbon granule or electro-magnetic, using sub-modulator A1134 or A1134A.

Valve complement:

MO, sidetone and modulator - two VT105 indirectly-heated triodes.
RF PA - two VT104 directly-heated pentodes.

Power input:

From 12 or 24V rotary transformers in air and sea-borne applications, or from ac mains via rectifier units in ground installations; 1200V at 200mA HT, 6V at 4A LT, 6 volts at 2.5A keying relay.

Power output

50 to 80W on CW, 15W approx on R/T and MCW.

Approx dimensions:

17 1/2" long, 16 3/8" wide, 11 1/4" high.


46lb 10oz.

Associated eqpt:

R1155 series receivers (10 variations), R1188 receiver (ground use), Antenna Switch Unit Type J, Power Units Type 32, 32A, 32B, 33, 33A, 33B, 34, 34A, 35 and 35A, ground Power Units type 114, 115, mobile Rectifier Unit Type 26, Aerial Ammeter 10A/12227 or 10A/12667.

Typical aircraft installation:

The T1154 would be powered by two rotary power units, one providing 1200v HT, the other 6V LT. These power units would also power the associated R1155 receivers. Two receivers could be associated with the T1154, one used by the WT Operator, the other by the Navigator. These receivers would have the facility to be be connected to DF Loop Aerial Type 4 and sense aerial for taking bearings (using the Rx 'magic eye' as an indicator) and homing (using left - right Visual Indicators type 1).

Audio distribution to and from the crew stations would be via an Amplifier A1134 or 1134A. This also provides impedance matching from the R1155 high impedance output to the crew's low impedance headphones. Some aircraft, notably those employed in radio and radar jamming duties, had a microphone fitted in an engine bay. This microphone could be switched through to the T1154, allowing noise jamming of enemy transmissions to take place.

Aerials would be selected by the transmitter range switch, giving access to MF (trailing) and  HF (fixed) aerials. Where necessary, the J Switch could be used to override the internal selection, giving access to the trailing aerial for HF and fixed aerial for MF use, and disconnecting the Tx 1200v when the DF facilities are selected for the Rxs or the aerials are switched to earth. In earlier installations a plug-board would be used for aerial selection. Facilities could be provided to share a separate sense aerial with a TR9F.  An on-board aerial ammeter would be connected in the HF aerial lead for aerial tuning purposes.

Typical high speed launch installation

A Cabinet Type 20 would house the wireless operator's T1154N and R1154N on Mountings Type 211, and would provide interfacing to the Power Units Type 33A and 33B. An R1155 A, B or F could also be fitted in the wheelhouse for the navigator's use.Also fitted are an A1134A AF Amplifier powered by an HT Power Unit Type 173 and a 2V 20AH battery, with audio distribution to the master, navigator, lookout and coxwain via a Panel Type 92. A Switch Type 495A would allow audio to be switched to the TR1133 / TR1143 radio equipment. Other associated equipments are the Impedance Matching Unit Type 111 feeding the navigator's low-impedance headphones from the Rx high impedance output, a Power Unit Type 35A supplying the navigator's R1155 via a Relay Unit Type 220, which disables the navigator's Rx when the Tx power unit is started, and a Resistance Unit type 52 to allow the input voltage to the power units to be maintained at a constant 18V. Later installations use the Voltage Regulator Type 33.

Aerials comprise a fixed HF and MF stainless steel wire, about 27 feet long, supported at the masthead by an Insulator Type 16, and at the ends by Insulators Type 17. The aerial input lead is made from Unispark 7 and is connected to the wire approx 10 feet from one end.  A Loop Aerial Type 3 and a sense aerial are also provided. A plugboard allows aerials to be selected for MF / HF, and to be earthed as necessary. An external aerial ammeter (stores ref 10A/12667) allows Tx aerial current to be monitored on HF, the Tx internal ammeter being in circuit on MF.


I'd like to know more about which aircraft the 1154/55 were used in. Please drop me an email if you can add to the list. So far I understand  they were fitted in the Lancaster, Halifax, Hampden, Sunderland, Anson, Lincoln, Lancastrian, York, Varsity, Stirling, Mosquito, Proctor, Prentice, Hastings, Briggand, Valetta, Shackleton (1951 to 1965), Manchester, Warwick, Albemarle, Botha, Wellington IC, II, III IV & V, Whitley V, Beaufighter, Blenheim IV, Beaufort.....

Thanks to those of you who have emailed me with additions to the list. Are there any more aircraft (or other installations) which you know of please...? 

Oh - and the NDB at Halfpenny Green (Bobbington) airfield was a T1154 in 1972...


Email G4NCE


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