# [time-nuts] Line Frequeny Stablity

Bob Bownes bownes at gmail.com
Wed Apr 5 19:39:12 EDT 2017

```In college we had a Vax 11/730 that would freak out and reboot the same time every day. Turns out the culprit was the sync pulses put on the AC for synchronizing the classroom clocks...But it took DEC a few weeks to find the culprit.

> On Apr 5, 2017, at 17:12, Bob kb8tq <kb8tq at n1k.org> wrote:
>
> Hi
>
> Back in high school, one of the radio club members figured out that the “clock adjustment” took place
> locally between 4:30 and 5:00 PM. Needless to say, pretty much everybody spent the next week listening
> to WWV and watching the clock’s second hand go out of sync with the beeps. This was back in the  late 1960’s
> and the idea of a grid was a bit looser than it is today. Indeed it was post 1964 so there *were* grids big
> enough to take out the whole north east section of the US. Since we were very much in that area the
> topic of grid sync came up. Nobody ever really had a good answer to that question. That included the
> guys who ran the local power company.
>
> Bob
>
>> On Apr 5, 2017, at 3:05 PM, Hal Murray <hmurray at megapathdsl.net> wrote:
>>
>>
>> preilley_454 at comcast.net said:
>>> When I installed power plants in the 1970's they has a special "clock"  that
>>> showed the cumulative error in terms of clock time.
>>
>> How big were the grids back then?
>>
>> What was the typical range of error over a day or month?
>>
>>
>>> If the generator ran a little too fast the clock would move forward.    As
>>> the operator observed the clock moving away from zero he would reduce the
>>> plant's  power and the clock would move backward toward zero.  ...
>>
>> Does that operator control a single generator or a whole grid?
>>
>> Does having a human in the loop help the control loop stability?
>>
>>
>>
>> --
>> These are my opinions.  I hate spam.
>>
>>
>>
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```