[time-nuts] Re: pulling some crystals

[Richard (Rick) Karlquist]

Great summary Bob.

Just wanted to amplify your point about the "dominant effect" syndrome.
When I was young and foolish 50 years ago, I believed the folklore
about Colorado Crystals "magic" glass enclosures:  unlike "dirty" metal
enclosures, the glass ones were ultra clean, which was "proven"
by the fact that they always drifted up in frequency, whereas
metal ones drifted downward.  Later, when I joined HP and met Jack
Kusters, he told me about the dominant effect syndrome.  His
philosophy is that if aging is not random, you have a dominant process.
He told me that he had eliminated as much as possible any such
processes.  Specifically, his copper enclosures were fabricated in
such a way as to eliminate outgassing of copper or whatever from the
can to the quartz that would bias the aging in the downward direction.

Rick N6RK


On 12/9/2023 6:40 AM, Bob kb8tq via time-nuts wrote:

> 2) Crystal aging and its modeling is a “fun” field to dig into. There are a lot of things that can make it difficult. The equations you see in various papers are useful. Often the data they use to demonstrate the fit is from runs that are not quite in the “typical” range …. errr ….  One typical gotcha is fitting an initial “retrace” sort of curve (which damps out in hours / days) and calling that aging. Another gotcha is that the worse the crystal, the better it will fit this or that curve ( = there is one dominant effect driving things).
> 
> 
> Bob
>