At one time, there were a number of big tx's (100kW+, dating from the 1930s)
over here in HF point-to-point service that used 'demountable' valves. These
were continuously pumped, and had replaceable grids and filaments. My
father-in-law worked on such tx's: he said that people with greasy hands were a
disaster, insofar as it took far longer to pump the valves down after replacing
a filament. They would wear linen gloves when re-assembling but even so, some
people's hands would still get some grease through. I was told they tried latex
gloves, but lubrication on the latex (talc) was even more of a problem.
I think the filaments were pure tungsten, as there were no facilities for
carburisation.
Peter G3RZP
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|