[arm-allstar] Redefining the NTP source

[David McGough]

Hi Dan,

You shouldn't need any scripting beyond the simple script in the October 
2019 post---and that script only needs to be run once to get everything 
going.

You are correct that the systemd-timesyncd daemon tries to update the time 
via network NTP servers.  With a local RTC, systemd-timesyncd should 
probably just be disabled entirely, like:

systemctl stop systemd-timesyncd
systemctl disable systemd-timesyncd


....Thinking about this further, the RPi internal clock will "drift" 
between reboots.  You should probably add the command "hwclock -s" as a 
daily cron job, so the the RPi is re-synced to the RTC on a daily basis.  
One way to add this to cron is with the "crontab -e"  command. Then place 
a statement similar to the in the root crontab file:

15 06 * * * hwclock -s


....That'll sync up the RPi internal clock to the RTC module at 06:15 
every morning.


73, David KB4FXC




On Mon, 27 Dec 2021, w2put at sbcglobal.net wrote:

> Howdy folks, here's an update in the event you are interested. After pondering my options I decided to persue the RTC. I found the one that Dave shared a link to also available on Amazon, but I didn't feel like waiting till February, so I ordered another version that didn't have the easy plug on header. The no header actually works best for me in this particular case.
> Using the script info that Dave so kindly shared a link to, some really good guessing, and enlisting the help of the Google, I eventually figured out what to actually do with the information. Scripts aren't exactly something I'm even remotely skilled at.
> After a couple hours of messing around I got it working on the desk in a test environment. I'm now very confident that I can easily repeat that in the field. So hopefully within the next week or so I'll have time to get to the site and implement it. Since it will have been more than an hour between figuring it out and implementing in the field I made sure to document how I did it because I knew I wouldn't remember exactly what I did if I didn't write it down. If anyone is interested in the doc I'll be happy to share it.
> 73Dan W2PUT
> 
> Sent from Yahoo Mail on Android 
>  
>   On Fri, Dec 10, 2021 at 8:37 AM, David McGough<kb4fxc at inttek.net> wrote:   
> Hi Dan,
> 
> None of the RPi boards include a Real Time Clock.  So, as you realize, 
> another source is needed.  The simplest, inexpensive, solution is a 
> battery RTC, such as this type:
> 
> https://www.ebay.com/itm/222920619499
> 
> This same basic board is available from many sources, the above listing 
> just being one example.
> 
> I've got perhaps a dozen of these RTC boards installed and they work 
> pretty well, a few seconds a month drift--obviously not as good as GPS, 
> but they're really simple and usually "good enough."
> 
> A setup script is here:
> 
> http://lists.hamvoip.org/pipermail/arm-allstar/2019-October/013331.html
> 
> 
> If you really need a precision time source, many little GPS boards are 
> available. If this is the direction you're wanting to go, I dig up links 
> to boards I've used?
> 
> 
> 73, David KB4FXC
> 
> 
> On Fri, 10 Dec 2021, "w2put--- via ARM-allstar" wrote:
> 
> > I have a repeater that is at a site with no normal internet, just when I'm on site for service and have a hot spot available. So last week while doing service I ran an update and it fixed the time announcement, and when I say fixed I really mean broke it because I had it disabled. The standalone Pi can't keep an accurate clock for anything, and now it's back announcing the time. Right or wrong. I can't find the details on how to unfix it again.
> > So what I was thinking of doing is using either a local Spectracom GPS Netclock for NTP via Ethernet or a USB GPS. Anyone know if and how either could be done? I kinda like having the time, but unless I can get a local NTP I'll have to figure out how to disable it again.
> > 
> > Thanks in advance,Dan W2PUT
> > Sent from Yahoo Mail on Android
> > _______________________________________________
> > 
> > ARM-allstar mailing list
> > ARM-allstar at hamvoip.org
> > http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
> > 
> > Visit the BBB and RPi2/3/4 web page - http://hamvoip.org
> > 
> 
>   
>