[time-nuts] accurate 60 hz reference chips/ckts

Tom Van Baak tvb at LeapSecond.com
Thu Dec 14 13:41:35 EST 2017


Pat,

> They drift a few seconds in the course of a few days, and wander back and forth.  

Yes, it's normal for AC mains to drift around by a few seconds over a day but it usually stays roughly on-time over weeks and months. Here's an old example of monitoring mains time & frequency for 45 days:

    http://leapsecond.com/pages/mains/

> Does a TCXO or similar exist in a small package that provides 60 hz ticks?

If you have 10 MHz (XO, TCXO, etc.) you can convert to 60 Hz using a $1 PIC divider:

    http://leapsecond.com/pic/src/pd60.asm
    http://leapsecond.com/pic/src/pd60.hex

/tvb

----- Original Message ----- 
From: "Patrick Barthelow" <apolloeme at gmail.com>
To: "Discussion of precise time and frequency measurement" <time-nuts at febo.com>
Sent: Thursday, December 14, 2017 8:42 AM
Subject: [time-nuts] accurate 60 hz reference chips/ckts


> PIcked up a couple of  large size Radio Shack  63-960 LED clocks with
> Settable alarm, at local Goodwill store. $3.00 ea work great see across
> room, loud Alarm, etc...
> 
> 
> Barely missed, by seconds, getting a classic Hallicrafters General coverage
> receiver
> (not like say, S-38) but a larger light green metal box. nearly perfect
> condx.  $25.00  with the famous h logo speaker  probably late 50s Vintage.
> :-(   Dang...
> Checked LED clocks by ear and eye with WWV, They drift a few seconds in
> the course of a few days, and wander back and forth.  Thought AC mains
> frequency was tighter than that. They use  an LM 8560 Clock chip.  Uses a
> switchable AC mains frequency reference pin  50/60 hz.
> Want to provide an accurate  (relatively accurate) 60 hz reference to the
> chip.   Some room inside for custom modifications.  Does a TCXO or similar
> exist in a small package that provides 60 hz ticks?
> 
> Best, 73,   Pat Barthelow AA6EG
> apol <apolloeme at gmail.com>loeme at gmail.com
> 
> 
> *"The most exciting phrase to hear in Science, the one that heraldsnew
> discoveries,  is not "Eureka, I have found it!"    but:*
> "That's funny..."  ----Isaac Asimov



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