 6 x 6 Loop Antenna
It uses one, six foot square, six turn loop, and is aperiodic in nature, covering the frequency range 50KHz - 5000KHz
Surveillance Transmitter Detector
This circuit can be used to "sweep" an area or room and will indicate if a surveillance device is operative
The ATL-3 Loop Antenna
The ATL-3 Loop Antenna. The Medium Wave Circle can be found on http://www.mwc.org
UHF Preamplifier
This circuit is designed to work at UHF frequencies in the range 450-800MHz. It has a gain of around 10dB and is suitable for boosting weak TV signals.
SW Receiver Using MK414
A Short Wave Receiver based on the MK484 (formerly ZN414) that includes the tropical bands and 49 metre bands
ZN414 Portable Receiver
An AM portable radio receiver made from the ZN414 IC. The ZN414 ic has now been replaced by the MK484 which is identical in performance and pinout.
4 Band Double Tuned Preselector
The input can be from a longwire or a loop antenna. The unit covers MW and Sw to 30MHz.
2 Transistor Transmitter
A compact 2 transistor transmitter for use at VHF frequencies
4 Transistor Transmitter
This circuit provides an FM modulated signal with an output power of around 500mW
Simple Field Strength Meter
This Field Strength Meter is simple and also quite sensitive. It uses an ordinary digital voltmeter to measure RF signal strength up to a few hundred MHz
Field Strength Meter
This is a wide band signal strength meter circuit which responds to small changes in RF energy, designed to be used for the VHF spectrum and will respond to AM or FM modulation or just a plain carrier wave
A bipolar regenerative receiver
Contrary to what some radio experimenters think, a bipolar regenerative design can be made to work efficiently
AM Receiver
This is a compact three transistor, regenerative receiver with fixed feedback. It is similar in principle to the ZN414 radio IC which is now replaced by the MK484.
FM Transmitter from David Sayles
A small FM voice transmitter for Band 2 VHF
2 Transistor FM Voice Transmitter
This circuit may be tuned to operate over the range 87-108MHz with a range of 20 or 30 metres.
Medium Wave Active Antenna
This circuit is designed to amplify the input from a telescopic whip antenna
TV Transmitter
A VHF band TV transmitter using negative sound modulation and PAL video modulation. This is suitable for countries using TV systems B and G.
FM Transmitter from David Sayles
This small FM transmitter circuit by David Sayles
FM OpAMP Transmitter Circuit
FM transmitter with OpAmp circuits
Op Amp Radio
Simple radio with operational amplifier circuit diagram.
Powerful AM transmitter
The circuit for a powerful AM transmitter. The range of the transmitter is expected to be one to two kilometers.
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