Introduction


This receiver is a beginner's and experimenter's dream. Easy to build. Easy to modify. Only eight easy steps complete the receiver. Each step is fully illustrated with each group of parts highlighted for quick and accurate placement. Building a receiver has never been this fun!

A large prototype section is placed in the middle of the board within easy reach of all the circuit areas. This section has two 8-pin layouts and 51 4-hole foil pads. Extra five volt, twelve volt, and ground connections surround the experimenter's area. Several modifications are illustrated in the document. Get ready to learn some hands-on receiver theory!

The receiver is a broadband design which can be used on any band from 20KHZ to 200MHZ. This is possible because all matching networks in the receiver use broadband transformers or capacitive\resistive coupling. The MMIC (Monolithic Microwave Integrated Circuit) amplifier can work from just above DC to light. The NE602's are rated to 500MHZ IF's (Intermediate Frequency) and 200MHZ oscillators. The Mini-Circuits T4-6T broadband transformers have a one DB insertion loss between 100KHZ and 100MHZ.

The layout is spread out so that fingers easily reach all the components for easy insertion and changing. The silkscreen shows both the values of the parts and the reference designator. This speeds up the assembly process and helps prevent mistakes. A universal layout is used for the crystals so that any type will easily fit.

The volume control is a diode attenuator placed at the output of the MMIC. The audio amplifier is a TDA2002 chosen for its simplicity, gain and low noise.

The tuning range can be customized to cover an entire band or just a small segment. The bandwidth of the crystal filter can be customized by using different frequency crystals and capacitors in the ladder filter. The audio amplifier frequency response can be skewed for highs or lows by changing one capacitor. A whopping 8 (eight) watts of speaker volume is known as "arm chair copy".


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Last Update: 01/07/2000
Web Author: David White, WN5Y