A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: David Iwancio
Date: 2020 Mar 4, 19:46 -0800
I don't know about other manufacturers, but the Casio radio-controlled watches I have experience with allow you to disable automatic synchronization, as an option within time-setting mode (where you'd at least set time zone and daylight-saving time). Manual synchronizaiton is started by holding down a "RECEIVE" button, while simply depressing it would display the time of the last successful synchronization (automatic or manual).
Of course I needed to know that because, left on its own, my current radio-controlled G-Shock gains about 0.7 s/day, so I end up with possible rounding errors after about 18 hours. I believe I can open the case and adjust its rate, but I'm squeamish about breaking the watertight seal if I don't "need" to.
On the flip side, a bare-bones waterproof Casio I bought new for 25 USD only gains about 0.1s/day. I feel like I bought a winning lottery ticket with that one.