Or, like I say above, just manually set your computer clock while watching an accurate time source, like time.is.
This is incredibly simple, really quick (a few seconds) and completely free. No extra gear to buy / assemble / make communicate with the computer etc. I very much doubt you could even connect a GPS module to a laptop or tablet in the time it takes to manually set the computer clock!
The only downside is that you might need to repeat the process if operating for longer than an hour. KISS principles apply.
I don’t know how convenient it would be on a tablet, but using my laptop with its keyboard, I found the easiest way to set the time manually was using the “TIME” command from a command prompt. There seems to be a slight delay when trying to use the Windows GUI “set time” option. Tethered to my phone, the meinberg ntp daemon does work nicely, but can take 10 minutes or so to settle. Giving it a quick manual nudge to start with doesn’t seem to upset it!
I wonder how well that would cope with the significant change in temperature from the PC’s home life to winter outdoors - not sure if that is a factor.
When the LF radio clock is dragging its heels - that’s exactly the circumstance in which I call up the time.is website on my smartphone. Fair enough, that does cost me an extra wasted 5-10 seconds.
There is always the possibility that the radio clock doesn’t get a lock and my phone doesn’t get a data signal - but it hasn’t happened yet in 292 datamode activations.
For my portable operations I use a GPS to set the time signal.
This does require me to carry an additional USB hub as my tablet only has one USB port, which is also used for the computer / rig interface.
Surprisingly the clock in the tablet does drift quite a lot.
i.e. for my last activation I set the clock on Tuesday night, and by my activation on Thursday evening the clock had drifted 8 seconds.
I do have a GPS receiver for the radio (IC-7100) but have yet to find a way to share the info back to the tablet.