Paul Burridge wrote in message . ..
On Tue, 31 Aug 2004 23:05:53 -0400, " Uncle Peter"
wrote:

It will oscillate at the fundamental, not the marked 100 MHz overtone
frequency. At 100 MHz, I'd guess that's a 7th or 5th overtone cut.
Most likely 7th, 20 MHz is about the limit for fundamental crystals.

So how does one tell if the xtal is fundamental or overtone? Not for
xtals marked 100Mhz, obviously, but for much lower frequencies which
could be either..

Easy. Look for resonances near 33.3MHz, 20MHz and 14.3MHz. Or...put
it in an oscillator circuit which favors fundamental mode and see
where it oscillates.

Cheers,
Tom