aftermarket HU= bad radio reception

I recently upgraded my HU to pioneer avh 1550. I noticed whenever I use the radio I get bad reception. I live in the province, but on my stock HU i still get clear signal on major radio stations (magic, monster) I went back to the shop to have my HU inspected, we changed the antenna adaptor, we tried a a brand new HU (same model) to no avail...Anybody experienced this before? My car is a 2013 city.

Thanks guys