A very small telephone VHF Adjustable Voice Transmitter Circuit that is
attached to the telephone wires that transmits both sides of the
conversation when the telephone is in use. When the alligator clips are
connected anywhere along the pole wires or to the red and green wires
of the telephone pair that runs from the jack on the outside of a home,
thru the basement, up thru the walls, transmits both sides of the
conversation to a discrete location blocks away.
It is primarily used in
clandestine or spy operations. The polarity of the clips does not matter.
C1 tunes the unit to frequency. C2 trims the antenna for maximum power and radiation. Use
a small flex wire antenna of about 18 inches.
L1 is made using # 20 copper wire. Use the smooth end of a 3/16 inch drill bit and air
wind 3 tight turns.
The unit is monitored using a VHF 147 to 170 MHz wideband tunable receiver.