I suspect that my Marine VHF radio is a little lacking in range, even on the
25W setting.

It's an older style Navico, I only get about a 10 mile range out at sea,
Yacht to yacht, although I can just reach the Coast Guard from around the
Eddystone (about 15 miles to the coast) This woulnd't seem so bad, except
my brand new ICOM M31 portable gives exactly the same range, both
tramistting and receiving, and that's using it down at deck level, and at
only 5W output! whereas my Main boat VHF has an aerial on the top of the
mast.

Does anyone have any thoughts about what range I can expect yacht to yacht
on a 32 footer sailing boat with mast head antenna with 25 Watts.

I am considering purchasing the ICOM M421, do you think this is the best
bet, or could the aerial be faulty. I have checked all the deck level
connections and these seem OK.

Tips and hints welcome.

Cheers,

John