It's bee a warm and humid day here at Lake Winnipesaukee. Thunderstorms are forecast for later. Nothing unusual about that by any means. But one unusual thing for those of you out there not being some kind of radio hobbiest: picking up FM radio stations from up and down the Eastern Seaboard.
While I was heading to the farm to pick up BeezleBub, the local NPR station was being interfered with and then disappeared, only to be replaced by yet another NPR station. (Yes, I admit it. I do listen to NPR. How else am I going to find interesting blog fodder without spending a lot of time online?)
WEVO, based in Concord, New Hampshire was drowned out by WUFT in Gainesville, Florida.
Another 'local' Boston station was overpowered by Ocala, Florida's WOGK.
Stopping on every frequency in the FM broadcast band I found a radio station. Every one. That isn't how it usually works because the FCC wants to maintain what are called 'guard channels' between radio stations, so you will rarely, if ever hear two FM stations on adjacent channels in the same area (an example: one station on 97.5 and another on 97.7. The other station will usually be at 97.9 or 97.1 on the FM dial. This keeps local stations from interfering with each other. But that isn't what I found today. The nearby stations came in loud and clear, but the weaker stations were either drowned out by the distant station, or you'd hear three or more station signals fading in and out as propagation changed.
I haven't heard radio propagation like that on the FM broadcast band in some time.
There are a number of causes, including thermal inversions in the atmosphere (colder air sits on top of warm air, creating something like a tunnel that allows radio waves that wouldn't normally follow the curve of the earth to travel hundreds, if not thousands of miles), weather front ducting (similar to an inversion, but it follows along the line where a weather front has formed), or the aftermath of a solar flare. Since we haven't had any solar flares in a long time (the Sun is the quietest it's been in almost 200 years), I think they can be ruled out. So that means it can be either of the other two, thought I'm not sure which one.
But still, it's kind of neat, isn't it?