[R-390] OT (sorta) - long - Vacuum tubes were the 4th largest US export i...

[Flowertime01 at wmconnect.com]

Chris,

Once you get over a 100 watts or so of transmitter power you are back into 
vacuum tubes.

Every big (more than 200 watt) AM, FM, Short-wave, Radar, Xray machine, 
Plastic melting bonding machine has vacuum tubes. And these are made in 
America. The process plants are old machines. For China to break into the business 
is a large up front expense and working against the many years of 
traditional customer relations.

So until the manufactures screw up big time they have a captive customer 
base.

The real big kilowatt tubes are very big bucks. It may be a billion dollars 
in sales but it is smallish volume and not real profit. If the plant was 
not paid for long ago when small tube volume was high it has long since bit 
the dust to other companies that had better financial bases. Consider that 
every AM, FM, short-wave station buts a full set of transmitter tubes every 
year. Maybe $50,000 per station per year.

A lot of the export is radar parts for stuff sold to other governments. Air 
traffic control, navy ships, other ships, military aircraft guidance 
systems. 

There are a lot of RF industrial applications.  A bunch of it is micro wave 
oven tubes.

There is a lot more kilowatts of RF in the air than you consider every day.

Roger AI4NI</HTML>