Also found the some of the 5 mile radios produced static when conversing with our 2 mile radios. Like the fellows had marbles in their mouth- couldn't understand half of what was said. Something to keep in mind.
jpc,
I believe that is because of the band width spacing that GMRS and FRS radios utilize. The FRS units are "2 mile radios" and the GMRS radios are usually labeled at "5 mile radios" because of the power output (though that is another story). Each uses slightly different spacing if I remember correctly. I would have to pull a manual out to verify that though.