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Larry wrote: Chuck wrote in news:1181052689_15255 @sp12lax.superfeed.net: Antenna heights are insufficient for reliable communication over that distance. The combined antenna heights would need to be more than 400 feet for marginal line-of-sight communication. I agree with Chuck. Marine radio is useless over-the-horizon more than 5% of optical line-of-sight. Contact your local 2-way radio shop and ask them about installing TRUNK RADIOS in both the shore installation and on the boat. The trunk radio systems use very-high-up digital repeater stations that are widely interconnected by computers that talk to the trunk radios, not unlike what a Nextel iDen phone does, but on a much more powerful scale. These trunk radio systems are shared by many diverse users, who rent service on them for a pittance of what the entire trunk radio system costs. Look in your local phone book under "2-way radio" or "trunk radio systems" or "radio communications". Professional communications, especially where life and limb might be in danger, is well worth paying for. It's why the cops all use trunk radio systems! Larry Ok, another Note here, from years of Parctical Experiencein the North Pacific, 50 Statute Miles VHF Range is very common between Commerical Shipping, WHERE the antennas are mounted on the TOP of the Masts, and about 75 to 100 Feet above the water. Comms with HIghSite USCG Stations that are in the 3000 Ft Range, above SeaLevel, are routinely carried out out to 90 Statute Miles from these Commercial Ships. In the Bering Sea it is very typical for the Crab Feet (Deadliest Catch type vessels) to have good VHF Comms in the 30 to 45 Statute Mile range, and significantly farther is they both are on TOP of the 30Ft Seas that typically run in the winter storms. I have Installed, Licensed,and Inspected, both Public and Private Coast Station, that have typical 30 to 45 Statute Mile coverage, to typical Fishing Fleet (less than 200 Tons) Vessels where the Coast Station Antennas are at the 75 to 100Ft above Sealevel and the Vessel Antennas are in the 30 to 45 Ft level range. In the US, VHF Limited Coast Stations are allowed 50 Watts Carrier Power AT the Antenna Terminal, which allows for higher powers at the Radio to make up for Feedline Losses. A good OmniDirectional High Gain VHF Antenna (Cellwave/Phelps Dodge Super Station Master) at the end of a 150ft run of 7/8" Heliax, with Beldon 9913 Jumpers, is about the best that can be done for a Limited Coast Station. It makes sense to put it (the coast Station) on the closest Hill, to the Coast, as possible for whatever elevation gain you can get, without sacraficing you limited range to Sea. Beyound that you loking at SSB, or in the modern era, a TracPhone or similar. These are going to cost you $2k to 3K by the tme you get them installed and provisioned. Bruce in alaska -- add a 2 before @ |
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