Original poster: Jim Lux <jimlux@xxxxxxxxxxxxx> At 11:22 AM 5/18/2006, you wrote:
Original poster: Shad <shenderson@xxxxxxxxxxxxxxxx> On Wed, 2006-05-17 at 19:28 -0600, Tesla list wrote: > Original poster: "Andrew Bonnell" <andrewbonnell@xxxxxxxxx> > > Out of curiosity, how fast to vacuum tubes switch? > > Andrew > <snip> Microwave tubes run happily well up into the Ghz range, though they're producing a different sort of power than we're wanting. The "acorn" tubes used in the Voyager probes run at extremely high frequencies, thanks to miniscule spacing between the plate and cathode.
I don't think there's any acorn tubes in Voyager. The only tubes in there are Travelling Wave Tubes (TWT), for S band (2.295 GHz) and X band (8.415 GHz), everything else is solid state. In fact, there's some of those parts in the display case down the hall from my office at work, including one of the X-band TWTs sawed in half lengthwise.
Info on Voyager Telecom: http://descanso.jpl.nasa.gov/DPSummary/Descanso4--Voyager_new.pdf
Probably have to go a bit farther back to find acorn tubes. I think that acorns were used in aircraft transponders at 1GHz. I think there's some of them in early telemetry transmitters from things like the Corporal and Sergeant rockets. I'll have to go look.
Jim