> I'd like to get some opinions and war stories regarding GPS reliability at > high RF level and elevation locations. At last count I’ve got ten GPS/GNSS active antennas scattered around the house (I have a very understanding spousal unit), including one in the kitchen skylight and one outside. We are currently in a sunspot cycle, and this summer has been an unusually active season. Several times I’ve seen one or more of my systems fail, sometimes for a couple of days at a time. I subscribe to the NOAA Space Weather Prediction Center alert system. https://www.swpc.noaa.gov/communities/space-weather-enthusiasts Inevitably about the time I’m thinking about swapping an antenna to see if it fixes the problem, I get an alert from the SWPC warning about a major coronal mass ejection event. I’ve finally learning to check the SWPC web site first before messing with hardware. I’ve also learned to check the systems before sunrise (I’m an early riser anyway) and after sunset. In each case the systems effected came back to working order without my having to do anything. Some antennas - regardless of location - seem to be affected more than others. (Why so many antennas? Five of them are GPS-disciplined NTP servers. Two of them are part of a little NTP/GPS monitoring system I built. Two are part of a Differential GNSS test bed I run 24x7. And one is just the test antenna to my work bench for whatever I’m working on.) - John -- J. L. Sloan Digital Aggregates Corporation +1.303.489.5178 3440 Youngfield Street mailto:jsloan@diag.com #209 http://www.diag.com Wheat Ridge CO 80033 USA