Standard L.F. and M.F. Receiver Outfit fitted in HM Ships and R.N. Shore Wireless Stations for a number of years including the World War Two period.
Reception: C.W., M.C.W. Voice
Frequency Range: 15 kc/s -550 kc/s
Power output: 2W into 600 ohm line for normal use
Power input: 1) 100/110 or 200/250v A.C, 2) 200v H.T.Battery D.C., 3) 6v L.T. Battery D.C.
Aerial system : vertical aerial or dipole aerial. For frequencies between 15-90 kc/s a high or low impedance loop may also be used.
Weight: 82lbs. Inst no. R/FR no.150.

More details:
VLF receiver covering 15 to 550 kHz in 4 ranges (15-38 / 38-90 / 90-240 / 240-550 kHz), AM/MCW, CW.
very low frequency receiver used for maritime communications and beacons, CRASH filter for front-end protection, R.I.S. filter for Radar Interference Suppression of signals from on-board radar equipment.
Used by the Royal Navy (B29, designations CDF (ship) and CDM (shore installation).