Type 46


1. 3N L/F - 1931
2. 3N H/F - 1931
3. 3N Spark - 1931
4. 4R - 1928


1. 3N L/F - 100 to 500 kc/s
2. 3N H/F - 3000 to 25000 kc/s
3. 3N Spark - 100 - 666 kc/s
4. 4R - 100 to 188 kc/s


1. 3N L/F - 8kW Motor Alternator. Filament Supply - 8kW Motor Alternator
2. 3N H/F - 8kW Motor Alternator. Filament Supply 8kW Motor Alternator
3. 3N Spark - 8kW Motor Alternator
4. 4R - 100V Mains. Filament Supply - 50 cycle receiving outfit alternator or 8kW Motor Alternator


1. 3N L/F - 450 miles
2, 3N H/F - World wide at times
3. 3N Spark - 40 miles
4. 4R - 30 miles


1. 3N L/F - 3 Valves
2. 3N H/F - 3 Valves
3. 3N Spark -
4. 4R - 2 Valves


1. 3N L/F - CW and ICW
2. 3N H/F - ICW
3. 3N Spark - SPARK
4. 4R - ICW




The Type 46 Series {46, 46M, 46X, 46Y, 46Z} and the Type 47, were SUBMARINE transmitters dating from the 1928 to 1931 period in design. They were still fitted in 1939 as follows:-
Type 46: (BASIC SET) - Seahorse, Sealion, Shark and Starfish, but the Type 46M is earmarked for replacement.
Type 46M:(MODIFIED SET) - Salmon, Seahorse, Sealion, Seawolf, Shark, Snapper, Spearfish, Starfish, Sturgeon, Sunfish, Sterlet, Swordfish - some fitted and some proposed fits (see above).
Type 46X: (1st experimental set) S/M H43, S/M L26
Type 46Y: (2nd experimental set) S/M L23
Type 46Z: (3rd experimental set) Sturgeon, Swordfish but both got the fully modified version, namely the 46M.

Type 46 (see above) - this range of sets were fitted into submarines as a medium power L/F-H/F valve set with Spark addition.

It consisted of four transmitters, the Type 4R being classed as a Harbour Exercise Set. The L/F set has two functions the first and obvious one to be the L/F transmitter when its output (by switched action - 19 on this picture) was routed to the aerial coil 11/13. If the deck and aerial insulators were drenched with sea water (spray when on the surface) and the L/F transmitter couldn't maintain aerial oscillations, the "dryout circuit" was brought into play. This involved switching the L/F transmitter output to the drying out coil 26/27 and pressing the Morse key for a few sections when hopefully the RF radiated would 'dry out' the dampness at the top end of the aerial coil to enable aerial current to be seen. Read this file for a full explanation of "drying out" Drying out circuit.

The Type 46 has four separate transmitters and one drying out circuit, which, with the exception of the Transmitter 4R (harbour exercise set)a are contained in six aluminium panels. Four of these panels are in two sections facing the Silent Cabinet (see PRE WW1 files) so that their controls and indicating instruments are accessible to the operator. The other two are fitted behind the other four and inside the safety screen with no operator controls needed. As per usual, all necessary transmitter operating switches and controls are fitted on the control panel which is sited inside the Silent Cabinet with the operator. Under Further Reading look at file Type 46 2G Controlling Board.

The variants in this series 'experimented' with different voltages and loads and different frequency ranges. The 46M had an HF, MF, Spark and Emergency Low Power transmitters, covering frequency ranges piecemeal between 100 kc/s and 25000 kc/s and power outputs to achieve ranges between 5 and 400 miles, whereas the Type 46X had an HF, MF and a VHF transmitter, the latter covering the range of 18750 kc/s to 20000. Just a few short months before this nomenclature was used, the HF of the 46X {7500-16700 kc/s} would have been called HF and the band just mentioned as being VHF viz 187500-20000, HHF (higher high frequency). The 46Y took the two bands of the 46X (HF + VHF or HF + HHF) married them into one band and redefined it 6700-25000 kc/s. The 46Z concentrated on power supplies required looking towards the 100V DC mark.


1. 3N L/F - 1492B (New Pattern)
2. 3N H/F - G7 and G8
3. 3N Spark - - 1492B (New Pattern)
4. 4R - - 1492B (New Pattern)


Type 46 Aerial Circuit
Type 46 Drying Out Circuit
Type 46 Full Schematic
Type 46 2G Controlling Board


Photos and Schematics


Photo 1 - Type 46 3N L/F schematic
Photo 2 - Type 46 3N Spark with condenser combinations - schematic
Photo 3 - Type 46 L/F Tx
Photo 4 - Type 46 3N H/F
Photo 5/6 - Type 46 Tx