[Milsurplus] FT-241 crystals question

[John Vendely]

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
>
>
> Sent from my Galaxy
>
>
>
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