Sunday, January 24, 2010

radio schematics

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. The design is simple and sensitivity and selectivity of the receiver are good.

Medium Wave Active Antenna
This circuit is designed to amplify the input from a telescopic whip antenna. The preamplifier is designed to cover the medium waveband from about 550Khz to 1650Khz. The tuning voltage is supplied via RV2, a 10k potentiometer connected to the 12 Volt power supply.

Q- Multiplying Loop Antenna
This circuit is designed to be used in conjunction with the standard 4 foot square loop used in MW for long distance reception.

ZN414 Portable AM 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 The ZN414 ic has now been replaced by the MK484 which is identical in performance and pinout.

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

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.

Radio Receiver Design
This tutorial will teach you in very easy steps how to design basic radio receivers. I will attempt to de-mystify most aspects of design by my usual extremely casual approach to an electronic tutorial. It doesn't matter whether you are a short wave listener, an A.M. radio dx'er, into hobby electronics or amateur radio design, the broad basic principles will still apply.

Build A One Transistor FM Radio
AM radio circuits and kits abound. Some work quite well. But, look around and you will find virtually no FM radio kits. Certainly, there are no simple FM radio kits. The simple FM radio circuit got lost during the transition from vacuum tubes to transistors. In the late 1950s and early 1960s there were several construction articles on building a simple superregenerative FM radio. After exhaustive research into the early articles and some key assistance from a modern day guru in regenerative circuit design, I have developed this simple radio kit. It is a remarkable circuit. It is sensitive, selective, and has enough audio drive for an earphone. Read more about theory behind this radio on the low-tech FM page.

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