Thread: Steampunk VFO?
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Old April 26th 10, 02:42 AM posted to rec.radio.amateur.homebrew,rec.radio.amateur.boatanchors
Scott Dorsey Scott Dorsey is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 774
Default Steampunk VFO?

raypsi wrote:
Hey OM:
From:
http://en.wikipedia.org/wiki/Alexanderson_alternator

"Because of the limits of the number of poles and rotational speed of
a machine, the Alexanderson alternator is at most capable of
transmission in the lower mediumwave band, with shortwave and upper
bands being physically impossible."

Says it all?


The number of poles is part of the issue, but you'd think with modern
machining technology you could make a big rotor with maybe a thousand
poles. Problem is that if you do this, the capacitance kills you.

One possibility to run an Alexanderson alternator would be to run it
into a nonlinear device and then select one harmonic out. Again, it's
very inefficient....
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."