For those of you who may not be familiar with them, Nelson Multimedia owns two AM's that broadcast the Timeless Favorites format on 1180 (WSQR) and 1480 (WSPY). I enjoy listening to them when I am driving out in the western suburbs.
I have noticed an interesting phenomenon during my travels out that way. When driving north on I-355 just north of the exit to eastbound I-290, you pass under three overpasses. If you happen to be listening to 1480 when you pass under the middle one (part of the ramp from southbound I-355 to eastbound I-290), you will observe something very interesting: the signal increases enormously in volume-- as a guess, something like 20 dB. The effect is very persistent and I have observed it every single time I've gone that way, but is very short lived at highway speeds (about a second). Usually when driving under an overpass, AM signals are attenuated, but in this case it is just the opposite.
Now that AM 1200 is operating from their new transmitter site with IBOC turned off, 1180 is very listenable out in the western suburbs. Before, I couldn't stand to listen for more than a minute. Interference from IBOC sidebands is more of a "screech" than a hiss on 2nd adjacent channels. How long this will last is anyone's guess, but I will enjoy it as long as possible. The signal from 1180 hangs in there pretty well until I get far enough north to the point where 1160 starts to overload my radio.
I have noticed an interesting phenomenon during my travels out that way. When driving north on I-355 just north of the exit to eastbound I-290, you pass under three overpasses. If you happen to be listening to 1480 when you pass under the middle one (part of the ramp from southbound I-355 to eastbound I-290), you will observe something very interesting: the signal increases enormously in volume-- as a guess, something like 20 dB. The effect is very persistent and I have observed it every single time I've gone that way, but is very short lived at highway speeds (about a second). Usually when driving under an overpass, AM signals are attenuated, but in this case it is just the opposite.
Now that AM 1200 is operating from their new transmitter site with IBOC turned off, 1180 is very listenable out in the western suburbs. Before, I couldn't stand to listen for more than a minute. Interference from IBOC sidebands is more of a "screech" than a hiss on 2nd adjacent channels. How long this will last is anyone's guess, but I will enjoy it as long as possible. The signal from 1180 hangs in there pretty well until I get far enough north to the point where 1160 starts to overload my radio.