[Amps] preserving tubes

[David Kirkby]

On 3 October 2012 06:20, Gary Smith <Gary at ka1j.com> wrote:
>
> Is there any benefit to taking a ceramic tube on the shelf and
> running it every so often and then returning it to the shelf to
> archive it for a backup when needed? Or os it just as well to let it
> sit until needed?
>
> Gary
> KA1J

I have heard it is worth at least running the heaters up, but I don't
know. This is the sort of information Reid Brandon at Eimac could have
provided!

I've often wondered if it is worth storing them in a vacuum - or as
close to a vacuum as one can reasonably get. There's going to be less
diffusion of gases into the tube if the pressure outside is very low.
If you stored them at a pressure of 10% of atmospheric (VERY easy to
achieve), then would it reduce the diffusion by a factor of 10?

As you try to get to lower and lower pressures, the difficulty
increases. I don't think you would need to go to the effort of things
like diffusion pumps.

I'll lot you lot think (argue) about that one!

Dave, G8WRB.