Just an idea I think might help.
Even on clear days, I've been turning on the weather radar and tilting it down 3 degrees.
When Approaching FL200 on descent into the major capitals, I reduce the map range to 10nm or 20 nm and look out for those little round blobs of "weather" that are really the reflections of other aircraft.
If you're flying with an older style radar where both pilots receive the same tilt, he or she may have to suffer alot of ground return on his or her map until you're back in Class C and tilting up a bit more again. I just tell them what I'm doing and there's no worries.
By the way, tilting the radar to 3 degrees down on descent is also good to do every minute or so to avoid not detecting those TCU at lower levels. How many times have they snuck up on you because you've had the tilt at say 1 or 2 degrees UP to avoid ground clutter on the map display, only to have a weather return appear at the last moment right in front of you.
If you tilt down to the angle you are descending at (usually close to 3 degrees) and look inside the ground clutter, you'll see them comming many miles away.
Hope this helps save someone's day!
