Radio circuit diagrams
Bug Detector
This circuit can be used to "sweep" an area or room and will indicate if a surveillance device is operative. The problem in making a suitable detector is to get its sensitivity just right; too much and it will respond to radio broadcasts, too little sensitivity and nothing will be heard. Read more...
Band 2 Preamplifier
This is a VHF amplifier for the Band 2 Radio Spectrum tuning approximately 88 - 108 Mhz. Read more...
The ATL-3 Loop Antenna
This antenna is the result of long term development and user feedback. Read more...
FM Stereo Transmitter
This is a small stereo FM transmitter. Output can be tuned from 88to 108Mhz and the transmitter can be battery powered or be used with the low voltage power supply on this page. Read more...
Portable FM Transmitter
A portable FM transmitter that can be used to replace a FM microphone. Read more...
2 Transistor Transmitter
A compact 2 transistor transmitter for use at VHF frequencies. Read more...
Antenna Tuning Unit
A simple passive (no power required) circuit to match an antenna to a radio receiver. This will be a useful addition to the short wave listener, but in addition a medium wave coil is almost used to tune the medium wave band. Read more...
SW Aerial Amplifier
A radio frequency amplifier to boost SW reception. Frequency range approximately 5 to 20 MHz. Read more...
Automatic Repeater
It is a self powered (audio derived) repeater circuit for receiving a signal and re-transmitting it via the other radio. Read more...
