[Milsurplus] 811/813 Tubes For ART-13 Transmitter

[Michael D. Harmon]

I have a couple of ART-13A transmitters, both came from British Air 
Ministry, both are made by Stewart-Warner.

I'd like to get a spare tube set put together, and I have questions 
about the 811 and 813 tubes used as modulators and RF amplifiers in the 
unit.?? ISTR that someone told me years ago that I should use ONLY 
original US-made 811's, NOT 811-A tubes.?? The same guy told me that I 
shouldn't use import 811-type tubes for some reason.

Can one of you gurus clarify this for me??? It's hard to find the 
original US-made 811 tubes, especially NOS tubes.?? I'm sorta dubious 
about paying money for "used" 811 tubes.?? 811-A tubes are much more 
plentiful, and the import 811-A tubes even more so.

How do the import tubes (Svetlana, Chinese, Taylor, Tesla, JJ, etc.) 
compare to the old original (NOS) US-made 811 and 813 tubes, especially 
in RF power amplification and modulation service?

Thanks for the help!

Mike Harmon, WB0LDJ

mharmon at att dot net