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10-13-2009, 06:13 AM
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Senior Member 
Join Date: Apr 2006
Location: SW Florida
Posts: 1,313
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4ft vs 8ft
Need to purchase 2 VHF antannaes mounted atop a "radar tree" which of course is mounted to the top of the cabin. The top of the radar tree (where the antannae would mount) is 10-11ft above the WL. Will be offshore fishing but generally not more than 40 nm. Would like have 4ft antannaes due to bridge clearance issues but also want range.
Question is: Will the 4ft-er's give me as near equal range as an 8ft-er when mounted atop the radar tree?
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10-13-2009, 09:32 AM
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Senior Member
Join Date: May 2006
Location: Ramseur NC
Posts: 231
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I just replaced my old 8 ft with a Shakesphere 5400 4 ft antenna that I received from BOE last week. I am very pleased with it and I think it is doing better then the 8 ft even when it was brand new. The 10 - 11 ft would really help with the 4 ft antenna.
For 40 miles I do not know, Jim will know better, but I was talking to somebody 23 miles away on Saturday and it was loud and clear..
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10-13-2009, 07:24 PM
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Join Date: Jan 2002
Location: Annapolis, MD
Posts: 9,186
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VHF is line of site. so the 8' antenna will work better, assuming we are talking the same grade of antenna. I don't know an exact figure, but Ii would guess the 8'er should go an additonal 5 miles over a 4'er.
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10-14-2009, 01:36 AM
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Senior Member
Join Date: Mar 2007
Location: Cape Cod
Posts: 1,507
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All other things being equal the 8 foot will reach out approximatley 1.8 miles further. then the 4 footer
__________________
All Those Who Wander Are Not Lost
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10-14-2009, 12:08 PM
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Senior Member
Join Date: Apr 2006
Location: SW Florida
Posts: 1,313
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Surfcaster - Did I read that correctly .... JUST an additional 1.8 miles?
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10-15-2009, 12:45 PM
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Senior Member
Join Date: Oct 2006
Location: Southern NH
Posts: 2,175
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Quote:
Originally Posted by chrisrack
Surfcaster - Did I read that correctly .... JUST an additional 1.8 miles?
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Yup. Here's a calculator:
http://www.qsl.net/kd4sai/distance.html
And here's maybe more info than you ever wanted to know about Marine VHF:
http://members.toast.net/boatguy/vhfant.htm
Ken
__________________
Tolman Jumbo 25 Pilothouse "Lucky C"
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10-15-2009, 02:29 PM
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Senior Member
Join Date: Apr 2006
Location: SW Florida
Posts: 1,313
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Thanks Ken - Yeah, the 1st site was very helpful; 2nd was TMI.
Love your Tolman. My long range plans are to build one similiar to your's w/o the forward cabin. Already have the book and read it 3 times.
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10-15-2009, 05:40 PM
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Join Date: Jan 2002
Location: Annapolis, MD
Posts: 9,186
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That's a nice calculator. Much shorter than I thought.
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10-17-2009, 04:18 AM
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Senior Member
Join Date: Apr 2006
Location: SW Florida
Posts: 1,313
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Jim -
Tried to order 2 VHF antenna's, 2 radios and maybe a 585 on Friday but Beth tell me you were busy swimming with the ducks in a pair of Noreasters at the Annapolis boat show. Give me a call on Monday.
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10-20-2009, 06:54 PM
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Admirals Club 
Join Date: Jul 2009
Location: Baton Rouge, LA
Posts: 922
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Man, I've talked further than 5 miles before with my 8 foot antenna. Something can't be right with that.
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31 Contender F 250s
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11-20-2009, 05:13 PM
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Senior Member
Join Date: Nov 2007
Location: Long Island, NY
Posts: 2,145
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Quote:
Originally Posted by Miss Trial
Man, I've talked further than 5 miles before with my 8 foot antenna. Something can't be right with that.
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It depends on the height of the antenna on the other end too. I can pick up the USCG more than 50 miles out with my 8' Antenna mounted 11' above the water - I think the CG antenna is 450' above sea level.
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