Radio circuit diagrams
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.
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This is a VHF amplifier for the Band 2 Radio Spectrum tuning approximately 88 - 108 Mhz.
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This antenna is the result of long term development and user feedback.
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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.
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A portable FM transmitter that can be used to replace a FM microphone.
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A compact 2 transistor transmitter for use at VHF frequencies.
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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.
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A radio frequency amplifier to boost SW reception. Frequency range approximately 5 to 20 MHz.
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It is a self powered (audio derived) repeater circuit for receiving a signal and re-transmitting it via the other radio.
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The 30 watt amplifier schematic shown below provides an appropriate power boost with an input of 4 watt up to 6 watts. The circuit is designed to cover 88-108MHz FM Broadcast Band.
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