8 Tube-1 transistor SW receiver
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This is an 8 tube - 1 transistor dual conversion superheterodyne Shortwave receiver. It covers the Shortwave bands from 5.7 to 18.5 MHz, and demodulates AM (amplitude modulation) signals only. This receiver has many features: signal strength meter for easy tuning, solid-state RF (radio frequency) amplifier for improved sensitivity and good reception with a short wire antenna, independent preselector tuning for perfect tracking, independent VFO (variable frequency oscillator) and mixer, crystal controlled second converter for high stability, dual conversion for excellent image rejection, 2 IF (intermediate frequency) amplifier stages with ceramic filter for high adjacent channel selectivity, and delayed AVC (automatic volume control) for improved S/N (signal to noise) ratio. Performance is excellent and the sound is smooth and clear. Receiver runs on 110 volts AC.
Controls from right: Fine tuning (top), RF tuning (middle), antenna gain (bottom), tuning and volume. On-off switch is on far left. A 9:1 reduction pulley offers smooth and easy tuning. Signal meter indicates signal strength and aids tuning. Speaker grill was cut from a pre-punched sheet and painted white.
Components were squeezed together to save space. Speaker was isolated from front panel to reduce microphonics (feedback from speaker to components). Potentiometer in the back zeroes the signal meter. Transformer at right isolates chassis from the mains. Cylinder behind transformer is power supply filter capacitor.
Not much space for anything else! The circuit was assembled with great care to avoid short circuits. Copper board on top left isolates antenna from first IF amplifier. 6 Zener diodes on small perfo-board regulate the VFO supply voltage. Full wave rectifier is on bottom right. Solid-state RF amp. is on bottom left.
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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