From: John Smith on Aug 21, 8:36 pm

Len:

LOL!!!


Traveling Wave Amplifier Tubes sounds like an interesting subject, one
which could really catch a guys interest! Especially after a drink or two
and some soft music... more than likely, takes a lifetime to explore
fully... grin

Ackshully, the industry acronym of TWT (Travelling Wave Tube) is for
a very interesting late-era vacuum tube, a very broadband amplifier
(at least an octave of bandwidth) having low internal noise and many
milliWatts of output, low (around 50 Ohms) In/Out impedance and
good from L-Band (1 to 2 GHz) on up to X-Band (8 to 12 GHz). The
Quail decoy missle used them in several applications, one as a
five-octave mixer (!). The Quail was made by MacDonnell (before
the amalgamation with Douglas) and carried on the BUFFs. It could
fly out along a predetermined course and act like one to three
BUFFs to Soviet radar. Good insurance for SAC.

The Electronic Warfare Labs at Ramo-Wooldridge Corporation made
the avionics package. I tested those cylindrical tubes in the
summer of '58, the same summer I decided on a major switch of
majors into electronics engineering.

TWTs are still being used in communications satellites as the
octave bandwidth final amplifiers, ideal since many, many
transponder channels can be amplified together, with very little
intermodulation distortion. TWTs are one of the last family
types of vacuum tube devices still useful and being used...the
others are CRTs (becoming scarcer and scarcer), photo mulitpliers
in optical instrumentation, the heart of Night Vision devices,
microwave oven magnetrons, and high-power VHF-and-up
transmitters.

Oh, and, in a few rare cases, vacuum tubes are used by beepers
in "state-of-the-art" vacuum tube transmitters they "designed"
in the 1990s... BSEG

I'm not going to touch the "other" acronym...would upset Kim and
Dee too much...not to mention certain pansy posters in here. :-)

ace nam