The folks at The College of Dupage are on the ball.
“It appears that the KRTX radar has suffered a hardware failure and is expected to be down a little longer. Here is more information from that NWS office itself: http://forecast.weather.gov/product.php?site=NWS&issuedby=rtx&product=FTM”
Following that link we find:
“KRTX update: Local technicians have determined there was major failure of a critical component. Technicians from the Radar Operations Center in Norman Okalahoma are expected to arrive Tuesday for further diagnosis. KRTX may be unavailable through at least Friday.”
So, there you have it.