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Electronic circuit : Infra Red Remote Control Tester

A simple IR receiver to facilitate in testing of Infra Red Remote Control handsets.

Electronic circuit : Laser Communication System

This is a simple Laser communication system. It can transmit and receive signal from any audio device.Communication distance is few meters. All components are not critical. Transistor 2N2222 may be on the coolrib. Laser diode is from laser pointer.

Electronic Circuit : MSF Receiver

This is an experimental 60khz direct conversion receiver for reception of the UK MSF Time Signal from Anthorn, Cumbria. (The mast array can be seen on the right hand image.) For continued stability, the radio should be continuously supplied from a +13.8v bench power supply.

Electronic Circuit : Tracking Transmitter

This is a small battery operated Tracking transmitter which broadcasts a repeating radio signal which can be detected by a directional antenna. The transmitter broadcasts an isotropic (radiates in all directions) signal on the FM band. An ordinary FM radio can be used to locate the transmitter, the reception of the signal will improve when the radio antenna is pointed in the direction of the transmitter.

Electronic Circuit : Long Range FM Transmitter

The power output of many transmitter circuits are very low because no power amplifier stages are incorporated. The transmitter circuit described here has an extra RF power amplifier stage, after the oscillator stage, to raise the power output to 200-250 milliwatts.

Electronic Circuit : 200W 136 kHz transmitter

 By : By Claudio Pozzi  http://www.qsl.net
My first transmission experiments on 136 kHz band where based on a little TX build around surplus components, particularly the output transformer was wound on a TV EAT transformer. In Italy is impossible to find Philips 3C85 cores.

Electronic Circuit : 136 kHz direct conversion receiver

I describe a simple direct conversion receiver, thinked for QRSS and DFCW communications, as companion of ARGO or SPECTRAN programs. I don't pretend to beat the performances of professional or commercial ham radio receiver,

Electronic Circuit : 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.

Electronic Circuit : 30 Watt VHF Amplifier

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. However, the circuit is very stable at my place and provides a clean-output through seven (7) element Butter-worth low-pass filter.

Electronic Circuit : 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.

Electronic Circuit : MK484 Radio with Loudspeaker

A complete AM radio set based on the MK484 IC (formerly ZN414). It uses a PNP transistor and can drive a 150R loudspeaker.

Electronic Circuit :Automatic Repeater

This circuit will be of interest to the radio amateur and anyone posessing two radios, (one of which must be able to transmit i.e. a transceiver). It is a self powered (audio derived) repeater circuit for receiving a signal and re-transmitting it via the other radio.

Electronic Circuit : FM Transmitter

A portable FM transmitter that can be used to replace a FM microphone.

Electronic Circuit : SW Regenerative Receiver

Sensitivity and selectivity are issues that will invariably concern a short wave listener when he wishes to purchase a new receiver. Commercially available communications equipment will undoubtedly fulfill his expectations, but we are talking here of highly priced products.

Electronic Circuit : LF Crystal Controlled Oscillator

The RF engineer sometimes has to look for an instrument that will check a low frequency quartz crystal unit reliably and rapidly. This is a difficult piece of equipment to find and the engineer often has to consult an electronic circuits handbook for the schematic of a circuit that will perform the task.

Electronic Circuit : A Bipolar Regenerative Receiver

Contrary to what some radio experimenters think, a bipolar regenerative design can be made to work efficiently. The major concern is the low input impedance of the detector-amplifier bipolar stage.

Electronic Circuit : Band 2 Preamplifier

This is a VHF amplifier for the Band 2 Radio Spectrum tuning approximately 88 - 108 Mhz.

Electronic Circuit : SW Aerial Amplifier

A radio frequency amplifier to boost SW reception. Frequency range approximately 5 to 20 MHz.

Electronic Circuit : 2 Transistor Transmitter

A compact 2 transistor transmitter for use at VHF frequencies.

Electronic Circuit : 6 x 6 Loop Antenna


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