My supplied antenna is positioned in the loft in BB10/BB11 area and I consider the range is reasonable bearing in mind the hills around and close to the town. I get a maximum range of about 130 miles for high level traffic in the directions not affected by nearby buildings rather than the 200 milesTarbat mentions but I’m happy with that.
As pointed out, the line of sight range is of course governed by the height of obstructions and the altitude of the aircraft, - because of the hills you won’t see aircraft at low level in/out of MAN, LBA. LPL etc from most areas of town.
I’m sure you’ll be well satisfied with your new toy whether you go for an external aerial or not.
Regards
Syd