It would be easier by far to build (or buy) your own external oscillator.
This will not only work with your S-108 but with anything else you might buy
down the road, and you won't have to hack holes in your radio. The basic
one is just a crystal oscillator with a 100kHz crystal. Fancier ones will
allow you to switch in a 1MHz crystal. I have an old Heathkit one that I
hopped up by adding a divider to get marks at 100, 50 and 25kHz for aligning
narrow-spread QRP receivers.

I know that any ARRL Handbook from 1930 to 1976 will have such a circuit --
I'd be mildly surprised to find out that a later one lacked it, but I'm too
lazy to get up right now and check. The 100kHz crystals are still available
from places like JAN Crystals and International Radio
(http://www.qth.com/inrad/). You can pretty much decide what you want the
thing to look like, select the appropriate date handbook and start cutting
metal.

"Allen McBroom" wrote in message
. 97.132...
I've had an old Hallicrafter's S-108 since the early 70's, and trying
to tell what freq I'm on is impossible. Does anyone know of a method for
installing a crystal oscillator on this old tube rcvr, or some other
method
of acurately determining which frequency the radio is receiving at the
moment?
Many thanks for the help!

--
Allen McBroom
www.NPSTKD.com
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