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On Sat, 19 Jul 2014, dxAce wrote:
But, after WWII there were a lot of military surplus crystals on the market. Crystlas are generally ground to order, but the military needed so much they just churned out crystals on specific frequencies. That was a bounty, lots of cheap crystals, which lasted decades. And they were so spread out that usually you could find one that was close enough. If not, you opened up the case, which back then was held together with a screw, and actually ground the crystal a bit, to bring it up in frequency. Had to be careful that you did it evenly or else the crystal might not oscillate anymore. And if you wet too far, you could lower it back a tad with some solder or pencil lead. Lots of people did that to get a crystal where it was needed, starting with one as close as possible (and you never could move them by much). I remember having to do that back in the 60's when I was a crystal controlled novice. Seems like I had some FT-243 crystals thaI either put some pencil lead on or had some very fine grit and ground them down on some glass. It always worked. The one thing back then was if one was calling CQ, you'd have to tune around some to find someone answering because they had a crystal on another frequency. And that was common. SInce the crystals were all surplus, they were on the same frequency (within toleranc). So if you stuck with the crystal off the shelf, you'd be on a frequency every other novice was using, and the novice segment was pretty small. If you shifted it a bit, you had a better chance of being noticed. And yes, the exact frequency didn't matter, since you had your crystal controlled transmitter and a separate receiver. It's already been 42 years since they changed the rules and allowed Novices to use a VFO. Michael |
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