I want to play with a "Garmin 18 LVC" GPS, for the purposes of keeping extremely accurate clock (sub-millisecond). Garmin 18 LVC is a little puck with cable coming out of it, that can be used for very precise timekeeping.
For best results, it should be outside, like on the roof or some other place highly transparent to GPS satellites.
Thusly, it needs to be protected from elements. So, my question is, what is the cheapest way to do so. I was thinking to just put it in a glass jar, and caulk all openings. Another possibility is to just enclose it in a big blob of epoxy. Has anyone tried anything similar?