THE CRYSTAL RADIO RECEIVER

HI FRIENDS, IT IS JAN 23, 2022. IT HAS BEEN SOMETIME. A NEW ACQAINTANCE BROUGHT UP CRYSTAL RADIOS TO ME AND MEMORIES JUST CAME BACK. I WAS 12 IN ZAMBOANGA CITY. FOUND A BOOK ON "FOXHOLE RADIO" AND I COULDN'T SLEEP TLL I BUILD IT. MAGNETIC WIRE AND HEADPHONES WERE THE EXPENSIVE PARTS. THE FOXHOLE RADIO USED A RAZOR-LEAD PENCIL DIODE. TOILET PAPER CORE WAS NOT A PROBLEM. I SCROUNGED TO BUY A SET OF HIGH IMPEDANCE HEADPONES. I FORGOT WHERE I GOT THE WIRES. VOILA, I BUILT IT AND IT WORKED! I PICKED UP 2 STATIONS IN THE CITY. I SAW A VARIABLE CAPACITOR IN MY UNCLE'S JUNK AND USED IT. VOILA, I WAS ABLE TO TUNE! LOOKING BACK, IT WAS TODAY'S TYPICAL CRYSTAL RADIO RECEIVER. 120 TUNS ON A TOILET PAPER CORE. ANTENNA AND GROUND ON EACH ENDS OF THE COIL. A CRYSTAL DIODE NOW COMMON, THEN A HIGH IMPEDANCE HEADPHONE. TUNING CAN BE BY ADJUSTING THE LENGTH OF THE COIL OR BY A VARIABLE CAPACITOR OR BOTH. READING ABOUT CRYSTAL RADIOS ALL THESE YEARS, I CAME ACROSS WHAT IS DESCRIBED AS ONE OF THE BEST IF NOT THE BEST CRYSTAL RADIO SET, THE THE MYSTERY RADIO THAT APPEARED IN AUSTRALIA IN 1932. IT HAD A UNIQUE GROUND TO EARTH. IT WAS NOT FROM THE MAIN TUNING COIL BUT ROM THE SECONDARY COIL FEEDING THE HADPHONE!

HELLO. TME O UPDAE THIS BLOG. I WILL POST FHE PCB GACE OF HE CMC 707 AM RADIO.

In my last post, I erased the audio amp section and the AM radio is nothing by a threwe transistor circuit. Well, we can reove the yellow IFT and the tranny after it. The white IFT connects to the rad oscillator coil. It becomes a 2 transistor radio!!! It will still work.

THE CMC 707 MINUS THE AUDIO AMPLIFIER. IT IS ONLY A 3 TRANSISTOR RADIO! THIS IS THE RF SECTION. ANY AUDIO AMPLIFIER CAN BE USED LIKE THE LM386.