speedhut GPS speedometer clock

[egchewy79]

Anyone have issues w/ the GPS speedo clock not changing times after daylight savings? I would've assumed that it would automatically switch. Can't recall if I noticed this the last time clocks changed. I tried downloading the instructions from speedhut website but the link's not working for me.

[michael everson]

As far as I know the clock is not GPS. Only the Speedo.
Mike

[egchewy79]

that's interesting. the clock (on the speedo, not the analog clock on the dash) is always spot on when compared to my cell phone time (except after daylight savings).
The dash clock on the other hand...

[michael everson]

Hmm didn't know there was a clock on the speedo.
Mike

[egchewy79]

it's one of the features you can toggle to...trip odo, 1/4mi time, elevation, etc.

[Papa]

GPS doesn't know anything about daylight savings, so the smarts to make those adjustments would need to be in the device that is displaying the time. Looking at the Speedhut instructions, I don't see anything about a daylight savings adjustment.

https://thefactoryfiveforum.com/attachment.php?attachmentid=192026&d=1699464315

[egchewy79]

yeah, i saw this too.
i assumed the GPS clock would pick up the local time, like my cell phone or like my car.
when i drive from one time zone to the next, my car's clock will automatically adjust as well.

[edwardb]

yeah, i saw this too.
i assumed the GPS clock would pick up the local time, like my cell phone or like my car.
when i drive from one time zone to the next, my car's clock will automatically adjust as well.

GPS time is UTC (Coordinated Universal Time) so they're the same worldwide. So good for minutes in our case. But not the hour and won't show local time zones. That's why Speedhut allows you to change the hour. Local time (cell phones, etc.) is coming from cell towers, networks, etc.

Edit: Forget about another source. There are also radio control clocks (we have a couple in our house) that originate from NIST Radio Station WWVB, which is located near Fort Collins, Colorado.

[egchewy79]

thanks for the lesson paul

[Ted G]

Clock? What's that?

[Theshandman]

GPS doesn't know anything about daylight savings, so the smarts to make those adjustments would need to be in the device that is displaying the time.

Right you are, Papa.

Basically, cell phones (and other IOT devices) get their time from the RF base station to which the cellphone/device is currently 'tethered' and revert to an internal clock when out of cell coverage.
Base stations in turn get their time data from GPS (UTC) but have s/w that knows about DST and their geographic time zone.

<uselessinfo>
I have (well, my pre-retirement company has) a useless patent that uses base station transmitted time info to set a VCR clock. It solved the question of "How do I program the time display on my VCR?" Of course a VCR would need built-in curcuitry and smarts to acquire and use such data (not to mention being physically located in cell coverage) and none that I know of ever implemented it; VCRs pretty much went out of useful practicality prior to IP streaming implementation in mainstream media devices.
</uselessinfo>

[Papa]

Right you are, Papa.

Basically, cell phones (and other IOT devices) get their time from the RF base station to which the cellphone/device is currently 'tethered' and revert to an internal clock when out of cell coverage.
Base stations in turn get their time data from GPS (UTC) but have s/w that knows about DST and their geographic time zone.

<uselessinfo>
I have (well, my pre-retirement company has) a useless patent that uses base station transmitted time info to set a VCR clock. It solved the question of "How do I program the time display on my VCR?" Of course a VCR would need built-in curcuitry and smarts to acquire and use such data (not to mention being physically located in cell coverage) and none that I know of ever implemented it; VCRs pretty much went out of useful practicality prior to IP streaming implementation in mainstream media devices.
</uselessinfo>

Now all your home entertainment devices as well as appliances, cars, etc. are connected and get time via NTP (Network Time Protocol).

[Papa]

GPS time is UTC (Coordinated Universal Time) so they're the same worldwide. So good for minutes in our case. But not the hour and won't show local time zones. That's why Speedhut allows you to change the hour. Local time (cell phones, etc.) is coming from cell towers, networks, etc.

Edit: Forget about another source. There are also radio control clocks (we have a couple in our house) that originate from NIST Radio Station WWVB, which is located near Fort Collins, Colorado.

GPS and UTC are different time references both based on atomic clocks. GPS time is continuous (essentially a count of the number of seconds since GPS Epoch) and UTC is adjusted for leap seconds relative to the GPS Epoch of 00:00:00 on January 6th, 1980. There are currently 18 leap seconds accumulated since GPS Epoch, so the GPS second count is offset from UTC by 18 seconds.