pretty much new to amateur radio have a couple questions about vhf

me and a couple buddies are planning on installing vhf radios in our jeeps. mostly for private off-road communication but also for communication during travel. most of the jeep forums recommend just using a cb radio, but i would like something for private communication (other people on the trail use cb’s). i also thought about using fmrs/gmrs, but i have used them and their performance leaves something to be desired. i have a nice set of gmrs radios that say they can reach 25 miles, last time i used them we barely got a mile out of them. maybe if i could find a model that had a remote mountable antenna the performance would improve. (any suggestions?) now my questions about vhf/uhf, are different models of vhf/uhf radios compatible? like if one of the radios is a motorola model x and another is a kenwood model z, do these two radios communicate with each other out of the box? if not can the be made to? i was looking to buy a couple of motorola gp68 hand held vhf radios and eventually a couple mobile ones. does any one have experience with them? thanks in advance.

Despite what the marketing people tell you, expected range from ANY pair of handheld radios is 1/2-2 miles in urban areas, MAYBE 2-4 miles in open country.

‘25 miles’, they don’t bother to tell you, is ‘IF both ends are on hills at least 150 feet tall, with no high ground between them’.

You should understand that ‘amateur radio’ is an entirely different thing, involving tests to get licensed, but which does allow more range due to repeater stations being fairly readily available… but NOT allowing business type use, and being oriented towards radio hobbiests, not ‘organizational’ use other than ham radio clubs, and some disaster preparedness activities for Red Cross and the like.

The GP68, for instance, is not allowed on GMRS or MURS (VHF) at all, and is usable legally only for licensed business radio or ham radio, though it’s a very poor radio for ham radio.

I was told that the GP68 is made in Hong Kong for export, and is not FCC type accepted to be used in the US. This means it has no warranty and I doubt any Motorola dealer would work on it if you have problems with it. There are an army of type accepted radios avail from Motorola, Icom, Kenwood, Vertex, etc. You could buy a mobile radio on the MURS frequencies and use an outside antenna. That would help your range considerably, however these radios would have to be turned down to 2 watts (not all mobiles can do this). I have sold radios to hot air balloons and their chase vehicle using this setup.