A pair of early Home-Built TRF sets

AC TRF set

click the pictures to see more
   

 Rear view of a partly dismantled home made set using a folded aluminium chassis.

This type of design is not too common for home constructors as it required hole cutters and a decent drill. The majority of sets used surface-mounted components screwed to a wooden baseboard.

Most home-made sets were battery operated but as the only valve that was fitted when I got this set is an S4V it indicates that this particular receiver was built for AC mains operation. Presumably the power supply and perhaps a loudspeaker were located in a separate chassis?

The front panel of the set carries two tuning controls indicating its configuration to have originally had a screened grid RF amplifier followed by a detector and single AF amplifier.

The front panel is a piece of wood-effect bakelite over a piece of aluminium. The latter would have provided the cure for hand capacity effects. This effect was annoying as when one's hand was moved away from the tuning controls the set would invariably detune slightly due to differing amounts of capacity to ground.

DC TRF Set

click the pictures to see more

 

 

 This set came from Swansea and is a more traditional type of home built receiver, being painstakingly constructed from wood held together by small brass screws. The material is a thin plywood, the same sort of wood that was used for shipping tea from India. Surely the right material for a home-brew set?

The valves are a mixture... an indecipherable Ever Ready (perhaps a K30?); a Mullard PM1LF and a new looking ex-government CV1246 (M-OV P2). It has two round shaped inter-valve transformers, a pair of "What are the Wild Waves Saying" basket coils fitted into a simple variometer device operated from a side-mounted control; a single glass resistor and a single green bakelite condenser.

The tuning condenser looks very old, having an ebonite frame and the filament rheostat is the simplest of devices, having no case.

The rear panel is quite interesting as it looks very early and is possibly a panel removed from a surplus WWI receiver or transmitter. Can anyone recognise it?


return to unusual page