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Radio electronic circuits

Am, fm transmitters, receivers, RF amplifiers, detectors, VHF, wireless microphones, spy bugs...

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. ... [read]

2 Transistor Transmitter

A compact 2 transistor transmitter for use at VHF frequencies... [read]

3W FM Transmitter

This is the schematic for an FM transmitter with 3 to 3.5 W output power that can be used between 90 and 110 MHz. Although the stability isn't so bad, a PLL... [read]

4 Band Double Tuned Preselector

The input can be from a longwire or a loop antenna. The unit covers MW and Sw to 30MHz. ... [read]

4 Transistor Transmitter

This circuit provides an FM modulated signal with an output power of around 500mW... [read]

4W FM Transmitter

Very strong FM transmitter. You maybe need license to run this.... [read]

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... [read]

73 MHz Hallogene Lamp Radio-Controlled

This circuit is a 73 MHz Hallogene Lamp Radio-Controlled. The purpose of it is to control the power state of a hallogene lamp by a remote control.... [read]

A bipolar regenerative receiver

Contrary to what some radio experimenters think, a bipolar regenerative design can be made to work efficiently... [read]

A small FM transmitter

This SMD FM transmitter has an operating frequency of about 80 to 115MHz. Under reasonable circumstances you will be able to receive its signal at a distance... [read]

AM FM Simultaneous Transmitter Using Digital IC

AM FM Simultaneous Transmitter Using Digital IC ... [read]

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... [read]

AM Transmitter

The circuit is in two halfs, an audio amplifier and an RF oscillator.... [read]

CB receiver

CB receiver... [read]

CB transmitter

Frequency of emission at AM: ~27MHz... [read]

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... [read]

FM OpAMP Transmitter Circuit

FM transmitter with OpAmp circuits... [read]

FM radio

Frequency of reception: 88~108MHz... [read]

FM Transmitter Bug

This small transmitter uses a hartley type oscillator. Normally the capacitor in the tank circuit would connect at the base of the transistor, but at VHF the... [read]

FM Transmitter from David Sayles

This small FM transmitter circuit by David Sayles... [read]

FM Transmitter from David Sayles

A small FM voice transmitter for Band 2 VHF ... [read]

Linear FM 50Watt with BLY90

A amplifier of force RF for the FM, is always essential for the amateur that wants it strengthens some small transmitter, that likely already it has manufactured... [read]

Medium range transmitter

This is a medium range transmitter circuit diagram. This is also improved by changing the values of the resistor.... [read]

Medium Wave Active Antenna

This circuit is designed to amplify the input from a telescopic whip antenna... [read]

Op Amp Radio

Simple radio with operational amplifier circuit diagram.... [read]

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... [read]

Small Radio Transmitter

The circuit is (of course) only mono, and accepts an audio input from either a microphone or other source. The input impedance is 1Mohm. The input sensitivity... [read]

Surveillance Transmitter Detector

This circuit can be used to "sweep" an area or room and will indicate if a surveillance device is operative... [read]

SW Receiver Using MK414

A Short Wave Receiver based on the MK484 (formerly ZN414) that includes the tropical bands and 49 metre bands... [read]

The ATL-3 Loop Antenna

The ATL-3 Loop Antenna. The Medium Wave Circle can be found on [read]

Transmitter FM 45W with valve

Force of expense: max 45W... [read]

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.... [read]

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.... [read]

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. ... [read]