TV Signal Booster

Telekit was one of a number of companies that offered television set kits in the late '40s. This booster was one of a few accessories they made, though it was offered only as an assembled unit. The shiny black panel and simple wooden cabinet was attractive and workmanlike. The rosette screws and bakelite knobs, off-the-shelf parts in 1949, indicate its utilitarian nature.

The circuit is a little unusual in that it is a switched-channel type, and there is a gain control. A single 6AK5 provides the amplification, with the gain control varying the screen voltage as needed. A variable capacitor provides fine tuning. Potential instability of the amplifier, a common problem with early boosters, is addressed -- crudely -- by loading the input and output with 300 ohm resistors, to offer a match to the usual antenna and TV set impedances. No provision is made for bypassing the booster when the power is off, another unusual "feature." The ubiquitous selenium rectifier made the plate voltage direct from the AC line, making this another "hot chassis" design. The large access/vent holes in the back of the cabinet present a shock hazard.

Updated January 30, 2007