Very true, sometimes a District 13 car will affiliate with the DuPage County or Cook County Simulcast site and I hear them up in the Chicago area. I've logged quite a few District 13 Radio ID's because of this. It's not about the antenna as much it's about the site you choose to listen to them on and your proximity to the site.District 13 is can be heard on at least a dozen sites in and near the district. If you are 25 miles from there must be a closer site.
I am about 25 miles from the tower. I don't think the quick key or group key matters, because I don't have any other channels programmed with quick keys.
Here is a link with a map of all Starcom 21 sites. Most of the sites away from the state line borders have approximately 25 mile range. The actual range of the particular site is affected by terrain and foliage. During peak summer months with all the crops and trees reduces range on Starcom just like cell phones.