3 Transistor-5 IC SW Receiver

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The drifting analog VFO is history!

This is a 3 transistor-5 IC dual-conversion superheterodyne receiver with continuous coverage of the SW bands from 5.7 to 22 MHz. It has a DDS VFO (Direct Digital Synthesis Variable Frequency Oscillator) and a back-lit LCD frequency display for accurate and drift-free tuning. It copies AM broadcasts and provides IF (Intermediate Frequency) output for copying SSB (Single Sideband) Radio Amateur signals with my homemade SSB Monitors. The receiver has the following features: an FET (Field Effect Transistor) RF amplifier for good sensitivity with a short wire antenna, 2 Gilbert-cell balanced mixers for clean signal conversion, 2 IF amplifiers with AGC (Automatic Gain Control) for good strong signal handling, 2 ceramic IF filters for good adjacent channel selectivity, a back-lit LCD frequency display, and a signal LED to show relative signal strength. The receiver runs on 12 volts DC and performance is on par with high quality commercial SW receivers.

Receiver schematic


Dimensions: 10"(L) X 5"(W) X 3"(H). Controls from left: Volume, RF Peak, Antenna Gain, backlit LCD frequency display and Tuning. Speaker jack is below volume control. Signal strength LED is above LCD display. Push-buttons for Memory Down, Memory Up and Memory Call are below LCD display. These buttons are used to adjust multiple functions of the DDS VFO such as tuning step and IF offset. Red push-button on top disconnects the antenna so I can peak the RF tuner by ear for maximum static. Red banana jack on top accepts a telescopic or long wire antenna.



Receiver back. Power on/off switch is on far left. Ground and antenna wires connect to black and red spring connectors. 12 volts DC supply connects to RCA jack on far right. 3-Pin jack next to the RCA jack supplies IF (Intermediate Frequency) signal to my homemade SSB Monitors so I can listen to Radio Amateur communications.



Inside the receiver. DDS VFO is green board on far left. Voltage dropping 5W resistors (white) next to the DDS VFO board supply the right voltage to the LCD display light. Receiver board is on far right. Manhattan style construction is used to connect and hold components on this board. All ICs (Integrated Circuits) plug into IC sockets. RF amplifier peaking capacitor can be seen below receiver board. Backlit LCD display is attached to receiver box with aluminum standoffs and modified terminal strips.


A short history | My radio background | Homemade radios | Tube radios
Transistor radios | World band radios | Kit radios | Reel tape recorders
My other interests | Pictures of Lebanon | Radio links
Home | Showcase | About this site

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