Most repeaters used to cover wide areas are sited as high as possible above the surrounding terrain, They have high gain antennas and the receive sensitivity is usually adjusted to be as sensitive as possible which aids in picking up the weaker signal of a hand held transceiver (HT or walkie-talkie or talkie). Our local Ham repeaters in this Texas county a co-sited on the Sheriff's VHF tower and the EMS/Fire local tower. Each site has 2 voice repeaters and a digipeater. They are about one mile apart. The voice repeaters at both sites are on the 2 Meter band (144.00 to 148.00mHz) and the 70 Centimeter band (420.00 to 450.00 mHz). The digipeaters are for packet radio and are on the digital allocation part of the 2 Meter band. We get these choice locations by agreeing to provide emergency communications during times of emergency and hold regular practice nets weekly. We have routine coverage to about 50 miles when using a mobile rig and 15 to 20 on a talkie. YMMV.
73,
Cal
Argh I got the 2 meter spectrum wrong. I forgot with my first scanner I picked up HAM from Imaging at about 20 MHZ higher. The kid that managed to summon help trasmitmed from the base of about a 3500-4000ft mountain across it to the repeater on the next mountain from that one.
I have two outdoor antennas that can I drive four scanners with. I took a TV Antenna and made a bracket to put the elements vertical the other antenna is a discone. I ran a lead from each antenna through a TV signal Amp 50 MHZ-900 MHZ then through a signal splitter going to the scanners. That's how I pick up several states away. I had maybe two birdies on frequencies that didn't matter but it worked great. Living on the side of a high ridge helps also LOL.
I'm lucky that all the agencies I want to hear are in the clear & either in the 150's 450's or 460 MHZ bands. I do have a trunk tracker though if needed. I also have the local HAM repeaters. Most of the time you'll know about a tornado a couple minutes before NOAA hits the alert.