Holdover, RTC for Pi as NTP GPS source
I have an analytical balance that reads down to micrograms. The weigh chamber is surrounded by three layers of IR absorbing glass so that radiated body heat does not induce convection currents in the air. I worked on a balance that had nanogram resolution (mostly wishful thinking in that spec). It operated in a vacuum. 30 bit mass-to-digital converters are rather finicky beasties.
It does not take all that good of a temperature sensor to detect changes in room temperature due to body heat (or fetching a beer from the fridge in the next room). You are basically a 100 watt space heater... even larger for the more corpulent folks.
Surely he'd want to be in an isolating suit to avoid introducing a nasty
warm body into his nice stable cave ?
From: Mark Sims
I have an analytical balance that reads down to micrograms. The weigh
chamber is surrounded by three layers of IR absorbing glass so that radiated
body heat does not induce convection currents in the air. I worked on a
balance that had nanogram resolution (mostly wishful thinking in that spec).
It operated in a vacuum. 30 bit mass-to-digital converters are rather
finicky beasties.
It does not take all that good of a temperature sensor to detect changes in
room temperature due to body heat (or fetching a beer from the fridge in the
next room). You are basically a 100 watt space heater... even larger for
the more corpulent folks.
Temperature is indeed the killer. My best Raspberry Pis for time-keeping
are RasPi-1 and RasPi-4, both of which are in an unheated cupboard not
exposed to sunlight, on the north side of the house with indoor patch GPS
antennas.
http://www.satsignal.eu/mrtg/performance_ntp.php
Cheers,
David
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-taylor@blueyonder.co.uk
Twitter: @gm8arv
? RasPi-4? Not released until 2019 AFAIK ... I have RasPi-3
-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of David J Taylor via time-nuts
Sent: 01 November 2017 16:08
To: time-nuts@febo.com
Subject: Re: [time-nuts] Holdover, RTC for Pi as NTP GPS source
From: Mark Sims
I have an analytical balance that reads down to micrograms. The weigh
chamber is surrounded by three layers of IR absorbing glass so that radiated
body heat does not induce convection currents in the air. I worked on a
balance that had nanogram resolution (mostly wishful thinking in that spec).
It operated in a vacuum. 30 bit mass-to-digital converters are rather finicky beasties.
It does not take all that good of a temperature sensor to detect changes in room temperature due to body heat (or fetching a beer from the fridge in the next room). You are basically a 100 watt space heater... even larger for the more corpulent folks.
Temperature is indeed the killer. My best Raspberry Pis for time-keeping are RasPi-1 and RasPi-4, both of which are in an unheated cupboard not exposed to sunlight, on the north side of the house with indoor patch GPS antennas.
http://www.satsignal.eu/mrtg/performance_ntp.php
Cheers,
David
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-taylor@blueyonder.co.uk
Twitter: @gm8arv
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.
From: David C. Partridge
? RasPi-4? Not released until 2019 AFAIK ... I have RasPi-3
My Raspberry Pi #1 and Raspberry Pi #4. See:
http://www.satsignal.eu/mrtg/performance_ntp.php
Cheers,
David
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-taylor@blueyonder.co.uk
Twitter: @gm8arv
Tbolt is a good oneBert Kehren
Sent from my Galaxy Tab® A
-------- Original message --------From: David J Taylor via time-nuts time-nuts@febo.com Date: 11/1/17 12:07 PM (GMT-05:00) To: time-nuts@febo.com Subject: Re: [time-nuts] Holdover, RTC for Pi as NTP GPS source
From: Mark Sims
I have an analytical balance that reads down to micrograms. The weigh
chamber is surrounded by three layers of IR absorbing glass so that radiated
body heat does not induce convection currents in the air. I worked on a
balance that had nanogram resolution (mostly wishful thinking in that spec).
It operated in a vacuum. 30 bit mass-to-digital converters are rather
finicky beasties.
It does not take all that good of a temperature sensor to detect changes in
room temperature due to body heat (or fetching a beer from the fridge in the
next room). You are basically a 100 watt space heater... even larger for
the more corpulent folks.
Temperature is indeed the killer. My best Raspberry Pis for time-keeping
are RasPi-1 and RasPi-4, both of which are in an unheated cupboard not
exposed to sunlight, on the north side of the house with indoor patch GPS
antennas.
http://www.satsignal.eu/mrtg/performance_ntp.php
Cheers,
David
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-taylor@blueyonder.co.uk
Twitter: @gm8arv
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.