The only "harm" in having unnecessary sites (too far away to receive) is it causes a little delay. If you have 10 sites each with 8 frequencies, it will add about 1 second of time before the scanner gets back to the appropriate site. (The scanner is checking each frequency for control channel data, sort of like conventional scanning through numerous frequencies.)
I'd suggest downloading all sites and set Location Control to On. Let the scanner sort out which sites should be on or off. Just be sure your zip code is correctly entered and you set your Range to something low (ten miles or less).
I'd suggest downloading all sites and set Location Control to On. Let the scanner sort out which sites should be on or off. Just be sure your zip code is correctly entered and you set your Range to something low (ten miles or less).