Inserted between the human and the radio, a PIC 16F628A keeps watch in both directions. On one side, the radio’s tank circuit is monitored to see what frequency the radio is currently playing.

Single-tube radios are a classic hack, and where a lot of hams got started back in the day, but there is a reason more complicated circuits tend to be used.

Its technology, though, radios that could operate from a single 6 or 12 volt power source, would live on in the form of the car radio until the early 1960s, when tubes were replaced by transistors ...

The radio components themselves were not small, the average tube of the day being about 4 inches tall. Credit Early magazine radio advertisement, P. Litwinovich collection. Early 1920s loop antenna.

Japanese designer Yuri Suzuki has created a functioning radio using Harry Beck’s famous London Underground map as a circuit board. Japanese designer Yuri Suzuki has created a functioning radio ...

Well it'd look like this. The circuit-board radio project is a collaboration between Yuri Suzuki and Masahiko Shindo, and uses Harry Beck's iconic tube map design.

The signals tended to be weak and required the operator to wear headphones to hear the signal. Edwin H. Armstrong invented a circuit that allowed people to hear distant radio transmissions without ...