Recommendation for a GMRS antenna for a sailboat

[dosw]

My sailboat has a marine VHF radio with transom-mounted VHF antenna, which is a terrible place to mount an antenna on a sailboat. My mast is down right now, and I am planning to install a new VHF antenna on the mast head before putting up the mast again. Shakespeare sells masthead antennas that seem to be what "everyone" uses for marine VHF on inland waters. I sail on the Great Salt Lake, so the maximum distance between two boats is going to be a little under 40 miles. And one would never be more than about 35 miles from either of the two shore stations (the two harbors). With a transom mounted VHF antenna, my signal to other boats with transom antennas fades after five to seven miles. With a masthead, which places the antenna 34 feet above the water level, I can communicate with other masthead-mounted VHF installations for about 22 miles, in my experience, and I can communicate with the harbormaster's VHF from pretty much anywhere on the lake.

 

That's VHF. But marine VHF has restrictive rules about how it can be used, and ship-to-shore is not really permitted unless the person on-shore has a land-station license. On the other hand, GMRS doesn't restrict ship-to-shore communications. So I'd like to also get a masthead GMRS antenna. Can I get a recommendation for a GMRS antenna for a 34 foot sailboat mast? Are there any GMRS antennas that have dual-band GMRS / Marine VHF capability? (Realizing that's probably a lot to ask). What cable should I be running for that distance? Consider 34 feet mast head to deck, then ten feet from the through-deck fitting to the GMRS radio. As for radios, I would probably move my MXT-275 from my vehicle to the boat, and then use that as excuse for getting a more feature-full radio for my vehicle.

 

Boat to boat, I would mostly still use VHF, since that's what other boaters on this lake use. But for convenient communications with family members within the harbor, or while out on the lake, talking to family on-shore, or talking through a repeater to family at home, I would use GMRS. (I've verified good repeater coverage for this application.)

 

 

[AdmiralCochrane]

Anything by Comet, Browning or Diamond.  In reality you could even use a Nagoya. Don't use RG8 coax that you have on your VHF, 65cm UHF doesn't propagate thru RG8 as well as VHF does.  Look for LMR-400 or equivalent. 

Marine band 156mhz (1.9 meter) is almost in the 2 meter ham VHF band, GMRS is 65cm is the next door neighbor of ham 70cm.  A dual band 2 meter/70cm ham antenna won't be PERFECT but likely close enough for both radios to be compatible.  My 2m/1.25m/70cm Comet tests pretty good for GMRS on a SWR meter and nanoNVA, well under 1.3:1 across GMRS. 

[SteveShannon]

I don’t know what’s necessary for a masthead antenna, but there are dual band commercial antennas like this Laird that target the right frequencies better than antennas for 2meter/70cm:

https://theantennafarm.com/shop-by-categories/antennas-mounts/mobile-antennas/vhf-uhf-dual-band/451-commercial-dual-band/219-high-gain-dual-band-antennas/8909-laird-connectivity-ab150-450cs-detail

[nokones]

There are several marine antenna manufactures and marine electronics dealers that can help you. Also, there are some that will custom build your antenna to your specs. You do have several choices and all you have to do is do the research and pick who you want to do business with.