(05-01-2017, 03:08 PM)Terry Wrote: My fault, Mike. There is nothing wrong with the formula but I omitted to tell you to format the cells to display the result as a percentage. (If you look carefully, 0.000197316 is the same figure as +0.0197316% - it's just the position of the decimal point that is different.)Hi Terry
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"What I want to understand is how to get the crystals to give out lower harmonics, so that they can be used as the manufacturer intended."
I'm puzzled by this as 'what the manufacturer intended' was for the crystal to be used at the frequency marked on it!
OK I understand what you are doing now regarding the %.
The manufacturer of the second crystal in the last table I posted, has marked the crystal as 4463.619 kHz, yet when tested in the circuit I made, it was oscillating at 10071.5 kHz. Why, or how, would a crystals properties change so that it would start oscillating at about 3 times its original frequency. My assumption was that it may be possible to utilise the crystal to produce lower harmonics, which could fall within the MW band.
My understanding of this was based on the conversations I had some while ago with a guy who sold me the crystals to make Trevor's circuit he posted on UKVRR in 2011. The crystals were marked at quite a high frequency (21.8Mcs).
But being as I cant get either to oscillate reliably in my circuit I wonder if he was making it all up. I guess they need to be tried in a circuit like Trevor's pantry TX to be sure.
Mike
