The Marconi R1155 is a World War II era receiver produced for the British Royal Air Force. It was used in Lancaster and Halifax bombers and includes special circuitry for direction finding.
The R1155 tunes longwave down to 75KHz and shortwave up to 18MHz, with a couple of gaps along the way. Fortunately the broadcast band is covered from 600KHz to 1500KHz, so there is still something to tune in today. Aside from the DF circuitry it's a fairly standard multi-band super-het with one RF stage, mixer-oscillator, two IF stages, detector, one audio stage, and a magic-eye tuning indicator.
An audio power output stage was not included as the receiver was only used with headphones originally. There is no internal power supply as B+ and filament power were supplied from an external source when installed in an aircraft. The unit below the receiver in the photo is a home-made power supply and audio amplifier, described further below.
Many of these receivers were sold as surplus after the war. In Canada they were sold by the War Assets Corporation (see advertisement: XTAL, Jan 1947). They were commonly purchased by hams. Many of them were then extensively modified, typically by removing the DF circuitry and/or installing a power supply or audio amplifier inside.