[Milsurplus] FT-241 crystals question

[Dave Merrill]

Aside from the few frequencies around 455kHz that were adapted for sideband
filters, what utility did any of the FT-241s have beyond their original
military use?

--... ...-- Dave N9ZC


On Sat, Jan 10, 2026 at 5:58 PM hwhall--- via Milsurplus <
milsurplus at mailman.qth.net> wrote:

> They are spiffy-looking though. :-)
>
> Wayne
> WB4OGM
>
> On Saturday, January 10, 2026 at 04:29:59 PM MST, John Vendely <
> jvendely at cfl.rr.com> wrote:
>
> Back in the late 60s, Esse Radio in Indianapolis had bins full of FT-241s
> for a dime each, and in those days, it was rare to find a bad one.  It's
> true that today, a good 50% of them have failed.  Some have obvious
> problems like detached or corroded bond wires, whereas the quartz elements
> of others seem to have mysteriously lost "activity".  A few years ago a
> couple of us decided to fire up the old SCR-508s and 608s.  Just for a
> laff, I tried opening some failed FT-241s, and if they were mechanically
> intact, ultrasonically cleaned them.  To my surprise, some came back to
> life.  Occasionally, you can still find individual FT-241As in sealed foil
> bags, and these have a much lower failure rate.  In any case, other than
> for use in the original radios, the FT-241 has essentially no utility
> today.
>
> The FT-241 was an unusually difficult crystal to produce, requiring state
> of the art techniques.  There were multiple attempts at setting up
> second-source FT-241 manufacturers, but none succeeded.  Only its
> developer, Western Electric, was ever able to mass produce FT-241s.  An
> FT-241 production line was built at ITT which showed some promise, but the
> war ended before it produced usable crystals in quantity, and the effort
> was terminated.
>
> For the truly hard-core who really appreciate this stuff, there's a very
> interesting and lengthy chapter with detailed technical info on Western
> Electric's complex FT-241 production process in the book "Quartz Crystals
> for Electrical Circuits" by Heising.
>
> 73,
>
> John K9WT
>
> On 1/10/2026 3:41 PM, Hubert Miller wrote:
>
> >
> These FT-241 LF rocks have a fail rate somewhere between 40 and 70%.
> Seeing that myself, dissuaded me from keeping any of them. I believe the
> only people who might want them are the vehicle militaria collectors.
>
> I have not myself seen any article on how to bring them back. Maybe two
> tiny pressure point contacts, that might get some resonant activity, but
> there's no longterm fix i know of.
>
> The 'Boatanchors' ham radio group a decade or so back, had a mass
> dispersal of an FT-241 lot someone had found. Known as "The Great Crystal
> Caper". I was sobered by the miserable results testing the crystals, and i
> wrote off keeping any of those series.
>
> -Hue Miller
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