Found in documentation from the 1990s, this circuit supports equivalent transistors. The range is on the order of a few tens of meters.
The presented circuit emits signals in the FM band, which can be picked up from a distance of a...
I found this circuit in a documentation for radio amateurs from 1975. The FET could be the BF245....
The traditional inverter amplifier configuration with the operational 741 shown in the figure is...