[time-nuts] Lowest Power NTP Server

[Bob kb8tq]

Hi

If you are going to run the beast on batteries, and talk to it via WiFi, what’s the lowest power
NTP server you can build? Timing source to keep it under a few ms would have to be included. 
GPS seems to be a reasonable choice. 

So far this seems to be the leading contender: 

https://www.researchgate.net/publication/332543537_BUILDING_A_RASPBERRY_PI_ZERO-W_GPS_NETWORK_TIME_SERVER_FOR_UNDER_50 <https://www.researchgate.net/publication/332543537_BUILDING_A_RASPBERRY_PI_ZERO-W_GPS_NETWORK_TIME_SERVER_FOR_UNDER_50>

Same paper at a different URL (thanks to TVB):

https://www.satsignal.eu/raspberry-pi/Schmidt-RPZ-NTP-2016.pdf <https://www.satsignal.eu/raspberry-pi/Schmidt-RPZ-NTP-2016.pdf>

Best guess is that it comes in around 0.5W. That is just a guess based on:

https://raspberry-projects.com/pi/pi-hardware/raspberry-pi-zero/raspberry-pi-zero-hardware-general-specifications <https://raspberry-projects.com/pi/pi-hardware/raspberry-pi-zero/raspberry-pi-zero-hardware-general-specifications>

and not (yet) a measured number.

Application is for off grid / remote / out of cell coverage timing of various “stuff”. Power is from 
a battery so fractions of a watt do count.  More or less, 0.5W on a 5AH 12V battery runs for
120 hours. Something at 5W only runs for 12 hours …..

Bob