>> From: Peter Chadwick <Peter.Chadwick@gpsemi.com>
>
...snip...
>> So why thoriated? Is it
>> much cheaper or what?
>
>It is cheaper AND the tube is more forgiving.
amen
>The grids are not gold
>plated, so that source of trouble is gone.
True, but 3-500Zs fail from a bent filament helix. [photo on p.15 in
9/90 *QST*}
>You can often heat the
>grids until they glow without grid damage.
True, as often as you like. I have done it in a 3-500Z and there was
apparently no damage. However, objects glow considerably at 700 degrees
C, and gold does not boil until it is heated to 2966 degrees C, so, I do
not see why a gold plated grid could not be heated to 700 or so degrees
without damage.
<... snip...
Rich---
R. L. Measures, 805-386-3734, AG6K
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