Providence, RI – This time on the Engineer's Corner let's talk about CODECS. Short for "encoder / decoder," codecs are a fact of modern life; used in cellphones, digital cable TV, digital television, the internet, you name it! Anywhere there's data, there's probably a codec involved.
A somewhat radio-related topic this time on the Engineer's Corner: Atomic Clocks! At NPR stations, like Rhode Island Public Radio, we rely on precision timekeeping because we coordinate our local programming with NPR's national programming via each end paying attention to a very specific clock. Everything is timed down to the second and, in some cases, to half-seconds! We use a special clock system from ESE to synchronize all our clocks in the studios. Such systems are expensive, costing thousands of dollars, because of their very high precision. But at home you can get pretty close by using an "atomic clock", available at most Radio Shacks, Walmarts and other, similar stores.
Welcome to the Engineer's Corner and since it's high summer I thought we'd talk a bit about TROPOSPHERIC DUCTING, an interesting and unpredictable phenomena that happens when it gets hot out, say, the mid 80's and hotter. When an FM or TV signal goes out into the upper atmosphere, if it encounters air that is warmer, instead of cooler, the higher "refractive index" can cause the signal to be bent. If conditions are right, it can be repeatedly "bent" into a "tunnel" or "duct" and carried for hundreds, if not thousands, of miles.