Congrats on your first airband scanner! You picked a decent radio but, as you are discovering, the antenna and placement of the antenna is much more important than the radio you choose. Most of the available radios have comparable receivers and the weak link is always the antenna and listening environment. By "listening environment" I mean how much receiver noise is received at the receiver location. Receiver noise can be produced by many things - light dimmers, AC power lines, cell phone chargers, cable TV...the list is long.
But the best thing you can usually do is place the antenna as high and in the clear as possible...then if you have noticeable issues with reception to start looking around for sources of noise. You can use your handheld radio as an initial aid in finding those sources of noise and there's a lot of information out there to aid you.