[time-nuts] Thunderbolt mounting

Hal Murray hmurray at megapathdsl.net
Fri Jul 13 07:14:53 UTC 2012


saidjack at aol.com said:
> We deal with big fans all the time, viz. Turboprop engines running at up to
> 2000rpm. Generates nasty massive spurs below 100hz.

2000 / 60 is 33.333 Hz

One man's noise is another man's signal.  (Or something like that.  I think I 
picked it up here, ages ago.)

How hard is it to measure the RPM of the engine if I give you the signal from 
an airplane?  (If they want to find you, the radar signal is readily 
available.  R^4th is ugly.)



-- 
These are my opinions.  I hate spam.







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