working with zenith angles over short distances the coefficient of refraction is typically, default value is k=0.14. That fits well enough spring to fall
However with longer distances in colder weather what is the appropriate coefficient of refraction?
I have an estimate. But I??m curious what others have been using.
fair weather, barometer 29.92, 48?øF. Given the cold waves of late the ground is pretty cold. My calculations returns k=0.3 which seems unreasonable. But?? it fits ?ÿ
?ÿ
Thanks. The formulae in those are useful. And fits.
Cold environments can produce some really intense heat waves. It's been the rule to take readings both directions and as close to the same time as possible. Also, the topography is very important, a point looking into a valley along a hilltop will have a different number than looking back up. The refraction calculations are estimates, it's best practice to minimize the errors inherent in the process.
I’ve done a lot zenith angle elevation in the Hagerstown MD valley to radio towers. So the vertical angles are somewhat large 1-3°. So not skimming.
Being well aware of winter I calculated k= and expected a larger value than summer but not 2x summertime value.
Just dusting off brain cells, using 100 yr textbook, and trying to avoid software package solutions. Not client work, and to towers recip ZA can’t happen. Distances are 50,000 to 120,000 and more, with delta elevation 1200-2100 ft. And a lot of redundancy (Starnet liked it.)
thanx.
I think 120,000' will be a big ask for the refraction calculation. I'm familiar with trig levels at 25,000-30,000 feet and they do well, but we would always do both directions. Good luck, Is there anyway you can confirm the calculations like a GPS point close by then a reflectorless reading?