[sdiy] A Frequency Standard for Poor People?

[Magnus Danielson]

From: "J. Larry Hendry" <jlarryh at iquest.net>
Subject: Re: [sdiy] A Frequency Standard for Poor People?
Date: Mon, 15 Dec 2003 20:38:11 -0600
Message-ID: <003501c3c37d$a64d06a0$ce6b2bd1 at oemcomputer>

> > All the frequencies in video are multiples of 60 Hz in US
> 
> Don't use 60Hz as a reference. :)  Power line frequency is constantly
> changing as it responds to the always present unbalance between generation
> and load.  In the USA / Canada eastern interconnect, normal hour-to-hour
> fluctuations are in the range of 59.97 to 60.03.  Excursions created by
> lagging response to load changes, or sudden unexpected loss of generation
> can easily double that.  While 3/100 of a cycle does not seem like much, it
> adds up when you multiply it by 100 or 1000.

Indeed. My HP521C counter is in standard edition tracking the 50 Hz or 60 Hz
of the powergrid. There is however a crystal oscillator option (which I got)
so that you don't depend on the not-so-exact frequency of the powergrid.

Cheers,
Magnus