Leaderboard

I would also suggest using a directional antenna for the VHF radio. Since Marine VHF is only legal to use when communicating between or with a boat, unless you live on an island, it is likely the water is within a specific arc from your home. Depending on how wide that arc is, you should be able to find a suitably matched VHF directional antenna. Any propagation loss you get from mounting the antenna below your UHF J-Pole would be offset by the gain. You should also look for an antenna that has low radiation upwards or downwards, since most boats tend to be at water level . And, make sure you mount it vertically. http://www.antennaskit.com/files/Yagi-4-elementi_30_150-300.JPG You can also use an outrigger as PastorGary suggested. That would work must better with a directional antenna than an omni, since the antenna mast itself would not be in the path of your beam - and would, probably, act as an additional reflector..

John E may have that formula somewhere - but that sounds close.