[time-nuts] "Confessions of a Reformed Frequency Standard Nut"
https://hackaday.com/2018/01/17/confessions-of-a-reformed-frequency-standard-nut/ "Or are you chasing that last digit just because it’s there?" ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Ships fooled in GPS spoofing attack suggest Russian cyberweapon
>In a car it is even easier. The car nav system KNOWS it must be on a >roadway. The car's ground track (positional history) must be on a road. That's assuming the GPS company keeps their maps up to date (it doesn't matter how often you update the maps in the device if the company's maps don't keep up with reality). New roads appear, old ones occasionally get moved. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Car Clock drift - the lowly 32kHz tuning fork crystal specs
>In your case, the car sits in an environment that matches their test >setup well. In my case �\200� not so much. FWIW, mine drifts pretty badly. It's in an aftermarket stereo, and I don't remember when I bought it (I moved it from my previous car). I assume that all quartz clocks and watches these days use "inhibition conpensation". https://en.wikipedia.org/wiki/Quartz_clock#Inhibition_compensation ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] DCF77 Analyzer/Clock
http://hackaday.com/2017/03/22/well-engineered-radio-clock-aces-form-and-function/ https://create.arduino.cc/projecthub/edr1924/dcf77-analyzer-clock-v2-0-c25404 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Temp/Humidity control systems?
>* You cannot "feel" absolute humidity, always measure it. And since this is time-nuts: Measuring humidity accurately is tricky. According to people who have tested them, commercial electronic humidity sensors, when tested in a lab, have never come anywhere close to the accuracy claimed in the data sheet. The best you can hope for is consistent readings, not absolute accuracy. The exception is the "cold mirror" type of sensor, which measures the dewpoint by cooling a mirror and bouncing a light off it to sense the temperature where dew condenses on it. Those are expensive, and they require maintenance to keep the mirror clean. BTW some of us are more sensitive to humidity than others. I can't tell you the RH of a room, but I can tell you when it's too dry for comfort. I want it as close to 50% as I can get it without growing mold on the walls. Some "experts" claim that 30% is good enough for anyone, but they're wrong. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Building a mains frequency monitor
>> A more modern name for a synchronous motor is a permanent magnet stepper >> motor. Any PM stepper, and a couple of microfarad capacitor becomes a >> synchronous motor when connected to the power line. I've seen a data sheet for a motor that's actually spec'd for both uses. I don't know how common that is. >The old pre-digital way of generating a rotating field for a synchronous >motor was a shaded pole. They worked well for low torque applications like >clock motors. I saw plenty of them when I was a kid. The rotor was hidden >in a package with the first layer of gears. I assume it was a permanent >magnet but never took a package apart to verify that. You're thinking of the Telechron clocks (also branded GE, Revere, and Herschede). Some good pics of the motors here: http://telechronclock.com/ https://clockhistory.com/telechron/ Also, lots of pics of the clocks themselves: http://www.telechron.net/main.htm There are people who rebuild the rotors, for a fee (usually they'll swap yours for a rebuilt one). I've fixed one clock this way, and I have a couple of others that need it. The other major manufacturer was Sessions, they had a bayonet system that allowed you to replace the whole motor easily (not including the gears), but they weren't as durable as the Telechrons. A friend of mine has an early Sessions clock where the motor is held in with #5 screws. I'd never seen these before, it took me a while to find the right wrench to take it apart. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Pendulum clocks based on John Harrison's writing
http://www.theatlantic.com/technology/archive/2016/01/pendulum-clock-john-harrison/424614/ |The contemporary British clockmaker George Daniels has called the text |“rubbish”; Rupert Gould, the author of the biography Burgess |read, described it as “gibberish.” | |Burgess disagreed. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
