Thread: elevator noise?
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Old April 5th 06, 12:30 AM posted to rec.radio.amateur.antenna
Richard Clark
 
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Default elevator noise?

On Tue, 04 Apr 2006 23:21:17 GMT, ml wrote:

anyone have any experience w/how much 'noise'/hash they might throw ooff?


Hi Myles,

Most controllers I've designed with were always "zero crossing"
sensitive. That means they did not add RF trash by switching loads at
high (or even modest) voltage levels. This is not to say when they
turn off the load as some controllers are proportional (using a part
of the voltage cycle).

For motor control, I have had to use very, very fast servos which
could tolerate an overvoltage of 10:1 of its usual rating (hitting a
10V servo with 100V for instance). I didn't give much thought to the
hash created because this was in a printing plant where I had to
accelerate a page of paper in milliseconds (takes quite a bit of power
to do this).

Do a noise survey with a portable SWL receiver, and visit a lot of
buildings with elevators. You can do a dnoise/dz sweep as the
elevator climbs.

73's
Richard Clark, KB7QHC