"I am often asked how radio works. Well, you see, wire telegraphy is like a very long cat. You yank his tail in New York and he meows in Los Angeles. Do you understand this? Now, radio is exactly the same, except that there is no cat." : Albert Einstein
Monday, February 21, 2011
RCA WR-99A Crystal-Calibrated Marker Generator
Well, what the heck is it?
Its a fancy radio frequency signal generator made by RCA (Radio Corporation of America) and used to service television and radios.
Original cost was approximately $260 and coverage was from 19 Mhz to 260 Mhz ( ... or 19 Megacycles to 260 Megacycles)
The frequency range is above normal broadcast bands so it is not really designed to service AM radios ... mostly FM radios and television sets.
A precise (hopefully) crystal oscillator provides markers every 1 Mhz or 10Mhz to aid in setting the variable frequency (it has an inbuilt heterodyne detector and audio output) or you can use a frequency counter like I have to accurately set the output. There is also a 4.5Mhz marker for IF alignment.
The switches probably need a shot of contact cleaner but otherwise it works just fine. Its not a piece of equipment that would be used very much nowdays but its an impressive beasty when it lights up and the band change controls change over with a satisfying thump.
Oh ... yes, it does have tubes that light up inside ... so qualifies as "real" radio equipment :-)