Hello Operators. If you've ever wanted to use a Raspberry Pi off grid & without internet, for ham radio data modes like WSPR, FT8, FT4, JS8, ... I've published a new tutorial for setting up a real-time clock in your Raspberry Pi. 73 Julian oh8stn
I am using something like this here at the QTH for time keeping. http://unixwiz.net/techtips/raspberry-pi3-gps-time.html
I've only quickly scanned through the video but did you use a GPS as well ? An RTC will eventually drift without constant time correction. It might only be .25 seconds per day but it will be too far out of sync quite quickly otherwise. A GPS is a good permanent solution as it can extract an accurate clock as long as it can see the satellites. I used PI's with RTC's in the past just to cover the gap when network time via NTP was not available.
Awesome. I've considered adding stratem Ok, perhaps not a very thorough scan. Augmenting the GPS with an RTC, was mentioned within the first minute of the video. The GPS is an excellent reference, but requires some time to acquire satellites before updating the clock. The real time clock provides accurate time instantaneously upon boot, augmentingthe HPS while waiting for acquisition. If it's out of sync, the GPS will update it, once satellite acquisition happens. They are definitely better in combination, than individually. Internet NTP is easy, but as mentioned in the video, getting operators to be less dependent on the grid, makes them better prepared for grid down scenarios as in California, or Manitoba. 73 Julian oh8stn GPS Tutorial
Thanks Julian - yes I admit I ran through it with no audio quickly - apologies for missing it. Very good point about mixing the GPS and the RTC. Good video - thanks.
A single satellite failure can happen, but a total system failure would be a pretty rare event. By using a more accurate RTC (they do exist), your drift could be such that you could go 30 days or so without a GPS lock to sync to, and still be within the FT8 (and others) timing requirements. Alternately, many GNSS receivers can pick up more that one system - GLOSNASS and Galileo are another 2 systems out there, so that could be used should there be a GPS system failure. However, a major solar storm could conceivably take out multiple satellite systems, but working HF probably wouldn't be in the cards anyway...