Whatever it's for, above 200 yards gets into trouble.
By 300 yards, you're in the red "danger" zone. ?
(Anyway, I'm thinking this meter reads "peak" distance, and not something cumulative over time.) A guess?
And it's in yards, not meters. Not sure that helps, other than it probably rules out something scientific, which would almost certainly use SI units of measurements.
The meter appears to be electrical, so something would have had to drive this meter.
This kind of meter takes very low current to operate, and it seems like it would be a steady-state DC voltage, else the needle might flop around like crazy and be too hard to read.
I don't know if any of that helps.
So, (assuming my statement above is correct), what kind of equipment might put out a constant, small DC voltage in relationship to some physical measured distance?
And, it's a pretty big meter face, at nearly 8-inches across. Possibly designed to be read from a considerable distance?
Update: Something just occurred to me....
Standard atmospheric pressure at sea level is 29.92 inches of Mercury.
That might explain the small "30" printed under the zero mark on the dial.
In short, this could be part of an altimeter.
