If you had the upgrade done less than a year ago it is still under warranty.
This is a problem with the supplier of the antenna.
Just take it back to the installing dealer and they will fix it.
If they don't believe you tell them to call TAC and ask them about it.
They are falling off like crazy because the company they got to manufacture the digital ones didn't do it right.
Give them a call and ask them before you bring it in.
I usually fix them with some new adhesive because sometimes the replacement ones fall off too.
You can get a roll of 3M double sided tape, I have a roll here, I'd have to do some research to tell you the best stuff if you really want to do it yourself.
If you brought it here I'd fix it no questions asked.
TAC is our Technical assistance center, they can call TAC and ask them about it.... TAC will tell them to fix it.