The RA17C18 is modified version of the RA17C12, having a delay
compensated IF amplifier and an additional IF output. It is a
North American version of the RA17, ie., it uses all BNC and
SO239 connectors, all fasteners have unified threads, and the
harmonic mixer (V4) is a 6AS6. It has no BFO, and the IF bandwidth
selector has only four positions: 13KHz, 6.5KHz, 3KHz, and 1.2KHz.
The receiver is instead equipped with a DC-coupled 'Video' output,
and a front panel 'DC Zero' adjustment which relates to it. The
'Shaper Level' control adjusts a peak-level clipping circuit,
which affects both the video and audio outputs.
The photograph below shows the solid-state power supply and the
specialised IF amplifier module. The set originally had a permanently
attached mains lead and a voltage selector, but these were replaced
(by the author, in ca. 1982) with an input receptacle and two
switched mains outlets for adapters (the 3-pole Belling-Lee connector
used is no longer type-approved in the UK and is scheduled for