We’ve gotten some calls about reduced signal around the area, and Engineer Bob said it’s due to Tropospheric Ducting. “Huh??” I replied.
from uk.sci.weather: “The speed of a radio wave in the atmosphere is determined by the dielectric property of the air. This property depends on the pressure, tempertaure and humidity of the air. In general as we move upwards through the atmosphere the pressure decreases and temperature falls. This means that the dielectric property changes with height and allows a slight increase in the speed of a radio wave as we move upwards through the atmosphere. This in turn means that if a radio wave moves away from the earth at an angle less than 90 degrees, then the upper part of the wave travels faster than the lower part. Therefore even under normal conditions this can in effect bend, or refract, the wave back down to earth.”
Well that was about as clear as mud! So in plain-speak, “The atmosphere is doing funny things to our radio signal.”
Bob put me onto a website with maps that show upcoming interference days (hint: Sunday and Monday are going to be bad signal-wise!)