1625 SHORTWAVE REGEN RADIO (6.5 TO 12.00 MHZ) - $70 - (Grand Junction, CO)
THE 1625 REGEN SHORTWAVE RADIO HAS LONG BEEN THE RAVE OF ONLINE CHATTER AMONG REGENERATIVE RADIO ENTHUSIASTS. I'M SURE IT IS SIMPLY BECAUSE IT HAS THAT OLD WORLD COLLECTIBLE APPEARANCE. I FOUND THIS ONE IN MY ARCHIVES OF PAST PROJECTS. I'VE MADE SEVERAL OF THESE RADIOS. THIS ONE LOOKS TO BE YOUR BASIC 1625 CIRCUIT, BUILT ON A WALNUT BREADBOARD. YOU WILL NEED 12 TO 14 VOLTS DC TO POWER THIS RADIO (AT LEAST 0.5 AMP CAPABILITY). I RAN A QUICK CHECK, USING A NEARBY KENWOOD RECEIVER AND THE BAND LIMITS ARE AROUND 6.5 AND 12.0 MHZ, AS DERIVED FROM THE REGEN OSCILLATOR SIGNAL THAT IT PUTS OUT. WITH A HIGH IMPEDANCE HEADSET CONNECTED I PICKED UP A COUPLE OF FAINT STATIONS. SHORTWAVE RECEPTION IS ALWAYS PRETTY UNPREDICTABLE, DEPENDING ON THE TIME OF DAY AND BAND CONDITIONS, BUT I COULD TELL FROM THE REGEN CONTROL AND BACKGROUND NOISE THAT IT WAS WORKING AT THE TIME OF TESTING. NONE OF THESE LITTLE ONE TUBE REGEN RADIOS WILL RIVAL A COMMUNICATIONS RECEIVER, NOR DO THEY TYPICALLY HAVE TONS OF VOLUME TO SPARE, BUT ON ANY GIVEN DAY, ESPECIALLY IN THE LATE AFTERNOON AND EVENING HOURS, YOU CAN USUALLY FIND A FEW SHORTWAVE STATIONS WITH ADEQUATE VOLUME TO DRIVE HIGH IMPEDANCE HEADPHONES. HI-Z PIEZO/CRYSTAL PHONES WORK WELL WITH THIS RADIO, BUT YOU CAN ALSO USE THE OLD STANDARD 2 TO 4K OHM INDUCTIVE TYPES, IF YOU LIKE. YOU'LL NEED A GOOD ANTENNA, AT LEAST 50 TO 100 FT. LONG, AND A GOOD EARTH GROUND. BOTH ARE ESSENTIAL FOR BEST PERFORMANCE. THE RADIO HAS MAIN TUNING, ANTENNA COUPLING AND REGEN CONTROLS. TYPICALLY I SET THE ANTENNA COUPLING NEAR MINIMUM, WITH A LITTLE MORE AT THE LOW END OF THE TUNING RANGE. TOO MUCH COUPLING CAN OVERLOAD THE THE GRID CIRCUIT, WHICH WILL AFFECT THE REGEN PERFORMANCE. A SLIGHT TURN OF THE COUPLING CONTROL WILL ALSO SERVE AS FINE TUNING. A GOOD RULE OF THUMB FOR REGEN RADIOS IS LOTS OF ANTENNA, A GOOD GROUND AND VERY LIGHT ANTENNA COUPLING. INCLUDED IS A HAND DRAWN ROUGH SKETCHED BLOCK DIAGRAM SHOWING WHERE TO HOOK THE POWER, ANTENNA, GROUND AND HEAD…
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From ebay.com - 1 month ago