[Amps] Coleman lantern chimneys for 3CX1200A7/Z7 and 3-500Z

[Steve Eldridge]

----- Original Message -----
From: <gdaught6 at stanford.edu>
To: "W0UN -- John Brosnahan" <shr at swtexas.net>; <amps at contesting.com>
Sent: Monday, February 02, 2004 4:39 PM
Subject: Re: [Amps] Coleman lantern chimneys for 3CX1200A7/Z7 and 3-500Z


>
> Remember that the 3-500 is a glass bottle, where we want lots of air
> flow external to the tube envelope.  The 3cx1200 tubes have the dense
> accordion pleated finned cooling structure, and the cooling airflow
> should go THROUGH the anode cooler, and little or none AROUND it.

Agreed, although if the blower is powerful enough a *small* amount of
air bled around the outside of the anode structure should not matter. It
could possibly be beneficial, but only if the fan, sorry blower, can do
the job.
>
> Just because the ceramic tubes might fit into a chimney doesn't make
> it a good chimney for them.

It doesn't necessarily make it a bad chimney either. An excessive gap
could be taken up with silicone compound in the right place, together
with a release agent (silicone grease?)applied to the valve anode cooler
during the prototype work. I haven't tried this yet, but see no reason
why not...

Another thought - Has anyone considered making their own chimneys from
scratch using fibreglass matting and resin, moulded around a suitable
mandrel, an old tube would be good, along with a release agent?

> Have I said that clearly enough, or is it too confusing?
>
> 73,
>
> George T. Daughters, K6GT
>
Clear enough, George!

73 Steve G8IZY.