On 17/03/17 00:03, Mike Baker wrote: > Hello, Time-nutters-- > > Any thoughts on what the likely accuracy of smart phone time > displays might be? I am thinking that the stacking of delays > along the path to its receive antenna plus any internal processing > delays would accumulate to some unknown degree. Any > thoughts on this? > > Mike Baker
Well.. Both the Android phones I carry (my Motorola "MoTo G", and a Samsung S6 for work, on different carriers here in the UK) are visually spot on with the Thunderbolt and Lady Heather's display, and with the various PC's I have NTP'd to the pool, or my local NTP server, and also with the BBC time signal on Analogue FM radio, and the various HF time-signal broadcasts. However... How would you get a low latency "time event" out of a phone to test it against something else, without introducing other indeterminate delays? I have in the past "Attempted" to use NTP over a mobile internet link, with terrible results. When it did get a response from a time server, the jitter was truly awful, in the multiple 10's of milliseconds range, and that was from a fixed location in the clear, with a good phone signal. As others have said, the GSM/3G network uses accurate timings internally, so probably the handsets do maintain good sync to that, and to whatever root standard the overall system is synced to. Be it GPS or ??? AndroiTS GPS Test (V 1.48 Free) is good, but a battery hog I find. On my Moto G, I find that it can handle not only the US GPS system, but three other systems too, including Glonass, and I think the new Chinese system. I don't recognise the last symbol, maybe Galileo. Not bad for a consumer gadget. I do not know if the phones could use GPS time directly, but that's only a software task at a guess. Regards. Dave B. G0WBX. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
