Ed Phillips wrote:
futuret@xxxxxxx wrote:I've heard that certain Chinese or Russian 833A's are not that great. Sometimes deals can be gotten on eBay for NOS American tubes. Of course you have to be careful on eBay. Some venders will let you return the tube if it's no good. JohnFor what it's worth here is a new note I got on the Tube Collectors list:"> > Anybody know where the tubes in this list are being made?> > http://www.rfparts.com/tubetran_specials.html <http://www.rfparts.com/tubetran_specials.html>> Chinese, of course! > Figured! All top quality of course? Let me put it this way. If you buy one, and put it in your transmitter, and it arcs over and destroys the power supply (which I have seen happenwith Chinese stuff many, many times),
You're saying that the HV power supply design didn't accommodate the possibility of flashovers? Fine for hackers, I suppose, who are willing to accept a rough and ready low cost PS design in exchange for the need for occasional rebuilds.
All tubes (even from Eimac/CPI) have the potential for flashovers, not to mention the odd spider crawling in. That's why they have limits in the data sheet for "stored energy" that can be dissipated in the tube. (typically a few Joules).
The LANL report "High Power Microwave Tube Transmitters" (or similar..) from William North (available in various places on the web) covers all this stuff in detail. (FWIW, North just recently died, presumably not from HV, although I didn't ask)
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