"David" wrote in message
...
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.

Did you have it when KFI was on the half-wave tower? The current antenna
lays down skywave as near as Rialto, Redlands and Moreno Valley to the East,
and the cancellation often makes the Mexican 640's in Juarez and Parral
equal in listening level in the post sunset period.