Hi

There have been several posts over the years noting that the “typical” wrist watch or quartz clock runs fast.
Indeed back when we (Motorola) made them, the target frequency for the oscillators was just a bit high.
The idea being that if you are late getting somewhere and “it’s the clock’s fault”, you don’t buy another
one from the same company.

Bob

Jim a interesting request.
The 4 clocks are going to drive you a bit crazy. They will drift this way
and that and then there are all of the time changes. I actually use 4 X 14"
clocks off of the same clock drive so they stay in sync. Just hate drifting
second hands. Big advantage seriously low battery drain.
But that said I started thinking about an alternative recently. There is a
lot of cheap technology out there like chrome books and tablets. Then there
are numbers of clock apps also. It may make sense to just get a small
tablet and a nice application. That can reach out to a time server and can
set time zones...
Thats my 2 cents.
Let us know what you end up doing.
Regards
Paul
WB8TSL

On Thu, Jan 7, 2021 at 11:59 PM Lux, Jim jim@luxfamily.com wrote:

Hi

If this becomes a DIY effort, there are a ton of add on displays out there
from a range of sources. Coming up with code to drive them can be any
where from drop dead easy to never get it going. My preference would be
to buy from somebody like Adafruit that likely also has drivers for them :)

Boxing up one or more displays should be fairly straightforward. Tying a
GPS module into an R-Pi or other simple “computer board” could be pretty
easy….

Yes, this has been a back burner project for a while ….

Bob

If I had to solve this I'd consider a cheap (~$53 US, delivered) 7" Android tablet:
https://www.banggood.com/512MB8GB-Allwinner-A33-Cortex-A7-Quad-Core-7-Inch-Android-4_4-Kids-Tablet-p-1636039.html?cur_warehouse=CN&ID=224&rmmds=search

Paired with an app like this:
https://play.google.com/store/apps/details?id=tm.app.worldClock&hl=en

No, I'm not sure the tablet does NTP, but it does have WiFi and could prove close enough. You might find it self-setting while shelf setting.

Bob L.

I had an old iphone sitting on my desk all the time showing the clock using
https://apps.apple.com/app/atomic-clock-gorgy-timing/id295302256 (Gorgy
Timing app). It was using my local wifi and using SNTP to connect to my
local GPS NTP server.

It worked great for a year or more, until one day I noticed a bump on the
iphone's case. It turned out the battery got swollen by constant use (it
was connected to a charger all the time). So it can get dangerous!

I guess more modern phones and tablets could do it better (trying to keep
optimal charge all the time, sometimes I even see a message that my iphone
won't charge now because my normal behaviour shows it won't be needed until
6AM, so it will charge later…). Also maybe using the smallest possible
current or setting some time switch for the charger will help, but I guess
most smartphones or tablets are not really prepared to work non stop.

Adam

On Fri, Jan 8, 2021 at 4:56 PM Robert LaJeunesse lajeunesse@mail.com
wrote:

On 1/7/2021 9:35 PM, Lux, Jim wrote:

MFJ makes a dual time zone, radio-disciplined clock for the US amateur
radio market that might meet your need if you buy two and are in the US.
They list for $70 ea.

https://mfjenterprises.com/collections/clock/products/mfj-148rc
https://mfjenterprises.com/collections/clock/products/mfj-148rc

What's not entirely clear is whether one of the two clocks is hard coded
to UTC.  There is seemingly conflicting information on the catalog page.
Both sides of the display have US timezone icons. The sales video says
that you can select the timezone of both clocks.

While they normally have all their manuals on-line, the manual for this
clock is not.  It has an empty folder in their cumbersome manual
organization.

Oz (in DFW)

Jim,
Not to sound greedy or anything, but if you have a Thunderbolt around, you
can use 4 of my kits and put them on different time zones :)
Didier KO4BB

On Thu, Jan 7, 2021 at 10:59 PM Lux, Jim jim@luxfamily.com wrote: