Something in the Air – The Reason One Radio Station Sometimes Bleeds Into Another
Few things are more annoying than getting in the car, turning on your favorite radio station (106.1 KISS-FM, of course), and hearing the station cut in and out, or hearing another station bleeding in. Sometimes the reason is something we can fix behind the scenes, but there are times, like earlier this week for example, there's not a darn thing we can do about it.
Ever hear the old saying, "Silence is golden"? The idea behind it being that sometimes it's better to keep your mouth shut then to spew some ill-informed drivel that makes you look like an idiot. That saying applies to almost everything but broadcasting. In our world, silence can be deadly. We want you to listen, and let us be a part of your day. However, when there's nothing coming out of your speakers, chances are you're going to change the station, and that makes us sad.
With that said, if given the choice, you'd probably prefer silence over the station cutting in and out, or completely different music from another station bleeding into it like what happened early in the day Monday.
We had a few people send us messages through Facebook saying they were hearing songs that didn't quite fit what they normally hear from us, and picking us up was difficult. Whenever we get messages like this, our first action is to alert our engineer, because he knows how everything works. Us? Not so much. We just push a button, talk into a microphone, and it comes out your speakers. It could be wizardry that makes it work for all we know.
Sometimes the issue is an overheated transmitter, a loose wire, or a faulty circuit on a piece of equipment. All things that a little time and a trip to the hardware store can fix. That wasn't the case Monday.
What jacked things up on Monday was something we couldn't control. Mother Nature. More specifically a thing called, "Tropospheric Ducting."
Here's the official explanation from the website, Engineering Radio:
This happens in warmer weather when there is a high pressure system nearby and is more prevalent over flat terrain. What happens is a warmer layer forms in the atmosphere above a cool layer...This causes a higher refractive index, which means that normally the signal would carry on out into space, however, upon encountering this warm layer it is bent back to earth. It can last a few minutes to several hours.
The site goes on to note severe examples of this phenomenon causing some FM frequencies to "travel 500 or more miles and override the local station’s transmitter site 15 miles away."
Think of it like this — let's say you're outside at night, and you point a flashlight into the sky. The light will only carry as far as the strength of the power source will allow it to. Stick a mirror somewhere in the path of the light, and it will reflect back toward you. If you had enough mirrors, you could theoretically reflect the light infinitely. In the case of Tropospheric Ducting, the radio waves are the light, and the mirrors are the warm layer above and the cool layer below. If there are no layers (mirrors), the radio waves will carry as far as the strength of their transmitter will allow. Put the mirrors in their way and they'll bounce around, allowing them to carry farther than normal.
The antenna on your car doesn't know any difference. It picks up every signal out there. You select the one you want by tuning into the frequency of the station you want to listen to on your radio. However, if you tune into 106.1 (which you should always do) and there's a station 50 miles away on the same frequency, or close to the same frequency either way down the dial (105.9 or 106.3, for example), that is carrying a little farther thanks to Tropospheric Ducting, your radio can't separate the two which causes the interference.
Now that you're in the know, if you happen to hear the issue again somewhere in the future, we encourage you to let us know by shooting us a message through our Facebook page or Twitter account. We'll pass it along to our engineer who can determine whether it's Tropospheric Ducting, or a difference issue he can fix (hopefully) quickly.