I've found that in the Midwest, they like a response even if they are busy.
I've found that down south when they are busy, they want you to keep quiet.
I try to go with the flow but realize that you don't know what the flow is
on initial call up.
Jim

"Andrew" wrote in message
ups.com...
I was flying through Chicago last night, VFR outside class B. The
controller was busy. When he said "01U radar contact, xx miles from yy"
I decided to not say anything back. He was busy talking to many
airplanes. A few minutes later, he repeated the "01U radar contact, xx
miles from yy". I guess he wanted an acknowledgement, even though he
was busy.