We found this circuit in the November 1974 Radio Electronics magazine. The capacitors determine the output time, and it is normal to obtain 1 second for each uF used.
The circuit consists of a MAT (Very High Voltage) oscillator that, applied to a protected metal...
A narrow range of frequencies around 1 kHz is rejected by the high Q filter shown in the figure,...
This transmitter circuit for the 27 MHz band uses 4 common FETs and has the details of the coils...