charger105 wrote:Hi ronaldheld.
I don't think the setting of one MkIV will have any bearing on what another should be set for.
My understanding is that the frequency adjustment compensates for oscillator circuits which are all slightly different (depending on the individual quartz crystal, capcitance of conductors in close proximity and capacitance inside the chip(?) etc.)....
This is correct. Thy individual crystal tolerances are the biggest contributor.
If you have the ideal setting for a given watch in off-wrist state, it is theoretically possible to derive the value for 1/2 on-wrist state (like "increase / decrease by 5" or so).
The theoretical temperature behaviour af a standard 32kHz crystal is depicted here:
http://dwf.nu/viewtopic.php?p=25336#25336.
But maybe the simplest way to find out is to wear the watch for a week and then re-adjust it. IIRC the Synchronar manual states how many increments to adjust for a given measured deviation.
Edit: found the Mark IV instructions:
The crystals we use run at their highest frequency at 75°F (23.8°C) and slightly slower at temperatures above or below this point. Therefore, depending on the wearing habits, climate, etc., a different optimum setting will be fond. Normally a setting of 48 seconds per year is required for a watch being worn every day versus one held at 75°F. This amounts to 6 digital increments on the speed setting scale.
That is, using elementary math:
- 1 increment means 8 seconds per year,
- 1 increment means 0.67 seconds per month,
- 1 increment means 0.15 seconds per week,
- 1 second per week means 6.5 digital increments,
- 1 second per month means 1.5 increments,
- 1 increment means 0.25ppm,
- 1ppm means 4 increments,
etc...