4 Transistor - 1 IC SSB Monitor

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Cq Dx, Cq Dx, Cq Dx, this is W7IOZ beaming to North Japan over the long-path and standing by... HAMS (Radio Amateurs) have been on the air ever since radio was invented. I am not a HAM myself, but I enjoy listening to HAM stations with a mug of coffee in hand. Here is the second of two SSB Monitors I built to use with my homebrew receivers to listen to SSB (Single Sideband) Communications. This monitor has the following features: An analog BFO (Beat Frequency Oscillator) which stabilzes in less than 5 minutes, an active cascode FET (Field Effect Transistor) product detector with good strong signal handling, and a low distortion IC (Integrated Circuit) AF amplifier with volume control for comfortable listening with headphones or a speaker. The monitor runs on 12 Volts DC which is supplied by the receiver.

Monitor schematic


Dimensions: 5"(L) X 4"(D) X 2"(H). Controls from left: Power on/off, Volume and LSB/USB. Phones/Speaker jack is below power switch. Power indicator LED is in the center. The LSB/USB control (capacitor) tunes the BFO (Beat Frequency Oscillator) inside the monitor to slightly above (LSB) or slightly below (USB) 455 kHz.



Monitor back. A 3-wire cable plugs into 3-pin jacks on the monitor and receiver to supply the monitor with the required IF (Intermediate Frequency) signal and 12 volts DC.



Inside the monitor. Circuit was built Manhattan style on a single copper board. Black Murata filters are upper left. BFO (Beat Frequency Oscillator) on the left uses a common white core IFT (Intermediate frequency transformer) and is adjusted for USB & LSB modes with an air variable capacitor (lower left). Cascode product detector is in the center. AF amplifier IC plugs into an 8-pin sockect at right. Volume control can be seen lower right.


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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