VHF units are line of sight for distance. The wattage output of a hand held is 3 watts on low power and 5 watts on high power. Than factor in the hieght of the anttenna and on a good day you can get out about 5 miles. Fixed mount units are rated for 25 watts on high power and 5 watts on low power and on a good day with a 8' anttenna properly mounted gets out about 25 miles. The higher the anttenna the more distance. I have a hand held with an adapter for a 8' anttenna that is mounted up in a tree about 30' and it still only gets out about 5 miles at 5 watts but on a good day I can hear guys out 50 miles. I can't transmit that far but I can hear them.