On Sun, 11 Nov 2007 20:38:11 -0600, "Pete KE9OA"
wrote:

I've noticed that effect when I get around 150 miles out from Chicago, on
WLS 890.

I'm about 1,500' above the transmitter altitiude for KFI and KNX and
about 50 miles sideways from them. I get severe selective fading
during twilight time.