If you don't want to digitally log the frequency or want .00000hz accuracy then use one of the "tuning fork"? indicators. They have a row of reeds (12 or 20, long time since I have seen one) that resonate at differing frequencies from a few hz.below nominal to nominal frequency and then to a few hz. above nominal.
It gives a quick at a glance showing of the frequency. Ones I saw were used to adjust the phase of generator to AC mains before switching back to AC mains. Cheers Will ZL1TAO > Sent: Monday, April 11, 2016 at 10:31 AM > From: "Nick Sayer via time-nuts" <[email protected]> > To: "Bill Hawkins" <[email protected]> > Cc: "Discussion of precise time and frequency measurement" > <[email protected]> > Subject: Re: [time-nuts] Building a mains frequency monitor > > > > On Apr 9, 2016, at 10:20 PM, Bill Hawkins <[email protected]> wrote: > > > > The schematic is too simple. There is noise on the power line from > > switching things on and off, leakage from dimmers and switching power > > supplies, and the occasional animal that gets across the HV distribution > > line, not to mention lightning, induced or direct. > > > > A simple capacitor will reduce high frequency stuff. The purist will > > invest in an L and C that resonates at 60 Hz. Alternatively, use a > > synchronous motor driving a load with sufficient inertia in combination > > with a slotted disk and photo pickup. Perhaps an old record turntable > > will do - but not one with a regulated DC motor. > > I invite you to perform the same experiment with and without the extra > filtering and report exactly how much benefit the extra filtering conveys. > Otherwise, it’s just Monday morning quarterbacking. > > > > > The science fair folks got enough interesting data without all that, but > > the precision is not known. > > So, the “science fair folks” is me. It wasn’t a real science fair entry, per > se. I titled it that way because it seemed to me to be a great idea for > someone to use in a science fair if they wanted. > > In any event, unless you’re suggesting that the data is wrong, then I would > assert that the precision was sufficient. Perfect is the enemy of good. > > > > > The link didn’t have any reference to code at all. > > Really? Did you miss the 3rd and 4th pages? The ones with the Arduino sketch > and the Linux monitor program? In C? That code? > > > > > This is a way of looking at frequency variations with natural causes > > that does not require expensive equipment, if done right. > > > > Bill Hawkins > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > If you don't want to digitally log the frequency or want .00000hz accuracy > then use one of the "tuning fork"? indicators. They have a row of reeds (12 > or 20, long time since I have seen one) that resonate at differing > frequencies from a few hz.below nominal to nominal frequency and then to a > few hz. above nominal. It gives a quick at a glance showing of the frequency. Ones I saw were used to adjust the phase of generator to AC mains before switching back to AC mains. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
