Took part in the flying display at Yeovilton one year. The first rehearsal there was no hack, everyone to use clock in their GPS for the timings. Second rehearsal we hacked, because somehow not everyone’s GPS clock was the same!

I have noticed anything up to 18 seconds time difference between GPS units in aircraft parked adjacent. I have tried many times to work out how this can happen. The only possible explanation I can find is that there is now 18 seconds of difference between the GPS system UTC and 'earth UTC' (there was no difference when the system was originally launched).

But even that doesn't really make sense. This time difference is accounted for by local updates to the GPS receiver unit. In several instances I applied the exact same update to both units, which apparently included the latest timing correction, and this still didn't cure the difference.

And thus defeated, I lost interest. My Casio, updated by radio signal, seems to always be spot on though!
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I was told that the original GPS time signal is still correct, it is the earth which has 'drifted'. An error correction signal to update GPS time to celestial time is updated regularly and broadcast by the satellites. Not all receivers can interpret this error correction nor apply it in a timely way. BTW internal GPS clocks are corrected for gravitational effects of relativity.

I have a Rolex, which is the only piece of jewellery I own, I have to accept that I need to update its accuracy regularly, but wouldn’t change it for a battery powered piece of plastic.

I own two watches, both made by Casio. One cost £7. In a fit of madness I bought another for £80 (the one updated by radio signal). My brother in law, also a pilot, owns many expensive watches. Mine are more accurate, and I can legitimately claim that I never have, and never will, own jewelry!

How boring life would be though if we were all the same!

This baby never lets me down !!
https://cimg5.ibsrv.net/gimg/pprune....4aa2a93733.jpg

I have one of those watches that keep their own time by allegedly reading the radio signal from Fort Collins (if you leave it on the right window sill overnight)

It cost me $1 from a garage sale, but the battery was no good so I had to spend another $5 to get a replacement - AND I broke the battery cover and lost the o-ring when I changed the battery but that's a different story

Then I realised the band was too large, so I had to spend another $7 to buy a tool to take out a couple of links

So my $1 watch actually ended up costing me $13. A cost overrun of 1200% which makes it sound like a government project

...and worst of all I don't even wear a watch

Digital TV and DAB should definitely not be trusted; the receiver takes a non-zero amount of time to decode the digital signal; quite easy to demonstrate if you have multiple devices which can be tuned into the same channel, as they're likely to embody different delays. I have no idea whether there's a (significant) additional delay at the encoding end, but it's plausible.

There are a lot of misconceptions about time! Your Casio Waveceptor, and my Citizen ECO-Drive both get their time settings from 60 kHz transmitters, MSF in Althorn, UK,
https://en.wikipedia.org/wiki/Time_from_NPL_(MSF)

(NPL = National Physical Laboratory)

and WWV in Fort Collins CO,
https://en.wikipedia.org/wiki/WWVB

I believe there is also a 60kHz station in China.

These are both synced to atomic clocks and have unquestionable accuracy.

There seems to be a misconception amongst many that these watches use GPS time, which is incorrect.

In my car I have an amateur radio set that uses GPS time, and it agrees exactly with my watch, as well as the Canadian Time Signal on 3330 kHz, CHU.

However, the Canadian Broadcasting Corporation, every day at 13h00, sends out the pips of the CHU station over its FM network, and they are 11 seconds delayed. They always used to be 1 second late, due to the propagation delay of the OC3 network, but recently somebody added a delay without realising that they were delaying the time signal!

Years ago, Rogers Cable TV put out the CHU signal 3-4 seconds late, due to satellite up-down delay. I managed to get that stopped with a phone call to a friend at the NRC. He has since retired so I cannot do anything about the CBC!

My Ford Escort also has a feature to sync to GPS time, but I have seen it up to two minutes out after syncing. Go figure!

'Windows time' was once notoriously erratic, until Bill Gates discovered TCP/IP. Using the internet, one can get atomic clock time from many research institutes around the world. I know, Victoria, you are going to say that there is a delay in the internet, but NTP (Network Time Protocol) cancels that but measuring the delay in getting a response and deducts half that when setting the computer time!

No, I don't have OCD. It's CDO if you put the letters in the correct alphabetical order :-)

'twas ever thus.

Culdrose Air Day, way back when.
Display briefing - "Puma? You are the sacrificial slot ahead of the Red Arrows, they will run to time, so if we run late do not expect to display".
Later that day......running out on our last display pass "Puma, any chance you could do your display again now please"!
I can only think it must have been a clock error.

PS We slashed our tail pylon with the tail rotor - It was the last Puma display for some years :(

lsh

I have a small Braun radio controlled travel clock which is my master time reference. But what surprises me is that my expensive Bose Wave III radio, which has FM RDS reception, keeps lousy time and the RDS function doesn't update the clock... Nor does the RDS radio in my car update the clock - why M-B, it's hardly rocket science!

My old VCR and DVR used to update from analogue UHF TV, but since that went off the air, I have to reset them manually every so often. Internet time isn't as bad as DAB or digital TV, both of which don't seem to bother with accurate time these days...

Progress? Hah!!

Anyone know how are they getting on at 3FTS with the 3 second cringes? Still a thing or quietly dropped because it made them look silly on the internet?

The Nav needed an accurate time check at Gander Flight Planning before our flight back to the UK. No time hack was available in house so he asked an Assistant if one could be provided. The Assistant assured him that it could indeed and disappeared next door into Gander Centre. He emerged triumphantly soon after waving a bit a paper on which was written "0652" or similar....

His name wasn’t Eccles was it?

It seems to have gone quiet but then, then again, I’m not on or have contacts in 3 FTS.