What would be the range difference if I installed a 5 ft vhf antenna on my 15ft boat instead of an 8 ft antenna with my fixed mount Horizon radio...or should I just go with the 8 ft antenna??
Remember, VHF is for all intensive purposes a line of sight signal. Where youre boating will determine if the distance gained from the use of the taller antenna is worth is useful or not.
The range of a VHF Marine Band radio is primarily determined by the antenna height above the water. It is also important that the base of the antenna be mounted in the clear and as high as possible.<br /><br />On a small boat like yours (15-footer), you will benefit most from increased mounting height more than antenna gain. Consider using a 4-foot extension to mount a 4-foot antenna. This will elevate the base of the antenna, and it will increase the overall effective height of the antenna (by two feet relative to an 8-foot antenna mounted at the same base).<br /><br />For further discussion of VHF radio range, see:<br /><br />Marine VHF Radio Communications <br /> http://continuouswave.com/whaler/reference/VHF.html
Good information above. Another good link below. 2 boats with 5 foot high antenna is about 5 miles. This would be like 3 foot antenna mounted 2 feet above the water. Your 5 footer mounted 2 feet above the water or 7 feet high to another boat with same setup would be about 7 miles. Many small power boats have 6 DB gain 8 foot antennas mounted 2 to 3 foot off the water and range between boats is 10 to 11 miles, but to 5 footer 7 feet high would be 8 or 9 miles.<br /><br />Still calling the Coast with their antenna mounted 2000 feet high on a mountain top the range is about 80 miles.<br /><br />On a small boat you should not get an antenna with more than 6 DB gain or 100 watts efective power. This 6DB gain helps when talking long range to the Coast Guard but makes very little difference when talking to another boat 10 miles away.<br /><br />Quality of the antenna make a big difference also. Antennas that do not flex as much appear to last longer. Brass and copper radior seam to capature more signal. My Favorite antenna is a Shakespeare Galaxy 5225. Any of the Galaxy serries are good quality antennas but there many other good antennas as well.<br /><br /> http://www.westmarine.com/webapp/wc...angId=-1&catalogId=10001&advisor=selecvhf.htm
