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VHF antenna height question
Need to install a new VHF antenna to a sailboat. Masthead would give max antenna height, but drawback would be longer cable and extra connectors. Have some experience about cable and connector losses being a ham radio operator, and therefore give serious thought to putting the antenna to top a a short pole on deck. Shorter cable, no need for extra connectors as this would be permanent installation. Plus much easier to install. Lower antenna height (some 3-4 meters instead of 14m in masthead installations) will of course reduce range, but would it stll be ok for costal waters. In my home waters some 20 NM range is quit enough to contact coastguard or SAR if needed. Mika |
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Mika wrote:
Need to install a new VHF antenna to a sailboat. Masthead would give max antenna height, but drawback would be longer cable and extra connectors. Have some experience about cable and connector losses being a ham radio operator, and therefore give serious thought to putting the antenna to top a a short pole on deck. Shorter cable, no need for extra connectors as this would be permanent installation. Plus much easier to install. Lower antenna height (some 3-4 meters instead of 14m in masthead installations) will of course reduce range, but would it stll be ok for costal waters. In my home waters some 20 NM range is quit enough to contact coastguard or SAR if needed. Mika The "line of sight" at 3 metres would be about 7-8 miles. Is that enough? |
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RG-8 to the masthead is pretty much a standard rig for masthead antennas and
if the connectors are well done the signal loss is acceptable. The benefit of the additional height far and away overrides any signal loss. Try to make the antenna cable in a single run from the masthead to the back of the radio - no through-deck connectors. If you don't want to run cable of that diameter, don't try for the masthead because the loss in the smaller cable over a run of that length would be pretty bad. Tom Dacon " Mika" wrote in message ... Need to install a new VHF antenna to a sailboat. Masthead would give max antenna height, but drawback would be longer cable and extra connectors. Have some experience about cable and connector losses being a ham radio operator, and therefore give serious thought to putting the antenna to top a a short pole on deck. Shorter cable, no need for extra connectors as this would be permanent installation. Plus much easier to install. Lower antenna height (some 3-4 meters instead of 14m in masthead installations) will of course reduce range, but would it stll be ok for costal waters. In my home waters some 20 NM range is quit enough to contact coastguard or SAR if needed. Mika |
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On Tue, 16 Aug 2005 13:47:27 -0400, Larry wrote:
( Mika) wrote in : Need to install a new VHF antenna to a sailboat. Put a 1/2 wave antenna as high as you can get it. 2000 meters is great! but the top of the tallest mast will do just fine. When you're screaming for help in a sinking boat, you can never have an antenna that's too high! The altitude of the mast antenna more than makes up for the length of the cabling losses. With a 25W Icom and 1/2 wavelength Metz whip at 55 ft on the other end of 30 meters of RG-58/U coax, Lionheart can call the US Coast Guard station way out of sight of land. but never, never, never ever use rg 58 cable. it's not shielded properly. it has high loss. --------------------------- to see who "wf3h" is, go to "qrz.com" and enter 'wf3h' in the field |
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On Tue, 16 Aug 2005 14:57:34 -0700, "Tom Dacon"
wrote: RG-8 to the masthead is pretty much a standard rig for masthead antennas and if the connectors are well done the signal loss is acceptable. The benefit of the additional height far and away overrides any signal loss. Try to make the antenna cable in a single run from the masthead to the back of the radio - no through-deck connectors. If you don't want to run cable of that diameter, don't try for the masthead because the loss in the smaller cable over a run of that length would be pretty bad. agreed. some folks have recommended rg 58 which has all the bad characteristics and none of the good ones of proper coax. --------------------------- to see who "wf3h" is, go to "qrz.com" and enter 'wf3h' in the field |
#8
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I have just seen a range of low-loss thin ad flexible 50 ohm coax -
aircell 7, ecoflex 10, ecoflex 15. If its as good as it claims to be, i would be great for use on boats for both HF and VHF. Has anyone used it? |
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