Gene Heskett wrote:
On Friday 28 May 2010, f...@kokkinizita.net wrote:
On Fri, May 28, 2010 at 11:24:29PM +0200, Ralf Mardorf wrote:
Oberhausen, Rheinland, Germany; power line frequency right now is at
49 Hz, measured with a low cost energy consumption costs meter.
Those low cost meters shouldn't be able to do correct measurements
;). The best test at home might be to compare the sound of a
transformer with a 50 Hz sine wave.
49 Hz is impossible. It would mean that a clock using this
frequency would be slow by more than a minute per hour.
Long-term accuracy is extremely high, precisely because clocks
depend on it. And since almost all of Europe is interconnected,
adjusting the frequency must be a _very_ slow process. So errors
of 2 percent really can't be tolerated.
Ciao,
[snip]
Yup, broadcast engineering can be a "but that can't happen (but it just
did)" scenario at least once a week.
[snip]
Full ACK :D. I once repaired a mic cable. The so called 'audio engineer'
who 'repaired' it before I did it, didn't know what a 'balanced'
connection is, he thought 2 cords and 1 shield must be a stereo cable
for a stereo mic. What he wanted was a connection that fit the mono
microphone to a 6.3 mm stereo jack for a consumer cassette recorder.
O'Toole's Corollary of Finagle's Law: 'The perversity of the Universe
tends towards a maximum.'
Veronica Merryfield wrote:
On 2010-05-28, at 3:26 PM, f...@kokkinizita.net wrote:
[snip]
Assume it at your peril. The usual spec is to arrange that over a given 24 hour
period, the total cycle count will result in a mains clock being within 1
second. Often, the power generators can get much closer and I believe these
days they use atomic clocks as the reference 24 hour time period.
The frequency will drop upon sudden demand. This is often coincident with the start of adverts in a national sporting event or high ratings soap, end of the news broadcast and so on. It takes a while to add more power and as a consequence the rotating machines will slow. Also, things like storm damage removing a significant section from the grid will result in an increase in frequency.
Vrnc
I don't think that we need to worry too much about the frequency. In the
morning, when all the people turn on all the coffee machines and
toasters, might be a bad time to adjust the H/V deflection for a
television set, because of the voltage that differs, but the frequency
should be stable. But indeed, during a snow storm the frequency will
drop extremely, but if so, we will hear about power blackouts in the
radio news, this happened e.g. in 2006 in Western Europe, there we had
around 49 HZ.
I guess even if it's OT, it's important. We won't a Hammond B3 become
similar to a tuning unstable Minimoog.
Indeed Veronica and Gene, I guess Fons is right. Yesterday evening it
wasn't 49 Hz, but a bad measurement done by my supermarket meter. But
who knows? Maybe the frequency really was down. Regarding to station
clocks I guess they are synced by radio and not by the power line. In
Parma there the clocks might be heritage-protected ;) and stills synced
by the power line frequency.
Cheers!
Ralf
--
Listen to Jasper van't Hof and Achim Jaroschek | Campus inter|national
#39 today in Leipzig
I can't be in Leipzig myself, but I saw some rehearses on video, when I
visited Achim and I'm sure it's worth it to visit their concert.
http://www.achimjaroschek.com/images/mediencampus_jaja.jpg
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