posted 08-28-2002 03:12 PM ET (US)            

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I do not know where I would put an 8' antenna, but on my 18' Outrage...

I have a shorter 3 - 4 ft (can not remember the exact leagnth) whip type antenna mounted on a Rail mounted adjustable base. The base is attached to the grab rail on the right side of the center console near the top of the windshield. When in the up position the top of the antenna is over 9' off the deck, When I put up the bimini I can tilt it down easily and then rais it again under the bimini. I have not noticed any reception problems.

It also makes it very easy to run the wiring to this location.

posted 08-29-2002 12:38 PM ET (US)            

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If you are not a fisherman, I would mount it on the gunwales near the stern.

If you are a fisherman, you'll want a different solution.

I don't like the metal whip antenna mounted on the grab rail. I am afraid it could start whipping around and poke someone's eye out.

There are 4-foot fiberglass antennas, but becaue they are usually commercial grade they often cost twice what an eight-foot antenna does.

Some solution would be to fashion a mount on the rails of the Bimini top. You could mount a small metal whip in that location, and it would not affect your fishing.

posted 08-29-2002 12:41 PM ET (US)            

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The effective range of VHF Marine band radios is determined more by antenna height than by antenna gain.

In most cases, if you need help, the USCG has very tall antennas with very good range. They'll hear you.

I would rather had an antenna with 0 dB of gain at 8-feet above the boat than to have an antenna with 6 dB of gain mounted on the boat.

posted 08-29-2002 02:32 PM ET (US)            

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I have the stainless Whip ant. and while I am not sure exactly how far I can broadcast, so far it is as far as I need it to be. (I boat mainly in Nantucket and Martha's Vineyard Sound). Reception is also quite good.

As far as Jim's comment of the whip antenna on a grab rail whipping around and hitting someone this has not been my experiance. My antenna is actually pretty stiff and even at WOT is not bending that much. It may just be a function of antenna selection, some may be stiffer than others. Also the antenna is mounted on the inside of the grab rail right before the bend that takes the rail around to the front. In the down position the whip is pointed straight down and is between the grab rail and the center console, very much out of the way. If I had a Digital camera I would post the picture for you, so you can see what I mean.

Jim, I think if you saw it you would not be concerned about having someones eye poked out except when it is being raised or lowered.

posted 08-29-2002 02:43 PM ET (US)            

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I use a Shakespeare 3' VHF antenna mounted on the Center Console forward Grab Rail.

Shakespeare sells 2 different models of their 3' Stainless VHF Antennas:
The 5240 is not as stiiff as,
The 5241 which is much stiffer and the one that I use.
It doesn't sway in the mind very much. As pointed out above, I use my boat mostly for fishing and don't want to hassle with transferring my Rod around an Antenna mounted on the Gunwale. The 3' Antenna also allows me to use the Bimini or Flying Top by angling the Antenna forward or backward a couple of notches in the Ratchet Mount.

posted 08-29-2002 03:03 PM ET (US)            

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I was looking for a pic of a boat with the whip ant mounted and came accross this pic of the an 8' ant mounted.

http://adcache.boattraderonline.com/6/0/8/31435908.htm

I still like the whip on the grab rail because it is out of the way (in my mind) and easy to wire.

posted 08-30-2002 05:16 PM ET (US)            

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Swellmonster,

I have a 3' whip (Gam makes a 3' whip at 6dB) mounted on the center vertical support for the grab rail that goes over the wind shield. It is mounted with a nylon ratchet base. By doing this it is mounted on the highest point of the boat and puts the top of the antenna 7'+ above the deck. Rotates down without tools for cover. I use the same set up on a t-top. No holes have to be drilled, no rusting parts and inexpensive what more can one ask when it comes to boating. ;-)
fwiw

posted 08-31-2002 09:10 AM ET (US)            

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Swellmonster,

I have a bimini also. I have two radios a submersible hand held and a fix mounted. I actually use the hand held as primary and the fixed as emergency. In which case I can drop the bimini and raise the antenna, if I use the bimini. The other big advantage to this set up, if you are casting the antenna can be rotated down and out of the way.
I find an antenna in any other location gets in the way, whether it's up or down and much more likely to get broken.
One other thought is to attach the nylon ratchet to the bimini support when in use and the grab rail when not using the bimini. The only tool you would need is an allen wrench.
fwiw

posted 09-05-2002 05:32 PM ET (US)            

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http://www.westmarine.com/webapp/commerce/command/ProductDisplay?prmenbr=201&prrfnbr=1745&store_num=3&store_name=Electronics&subdept_num=136&subdept_name=VHF%20Radios%20%26%20Communications&class_num=139&class_name=SSB%20Radios,%20Antennas%20%26%20Tuners&outlet=

I am not sure how to describe my attenna so i listed a website with a picture. basicaly it is an 8ft shakespare attena that is slightly flexible. it is mounted on the starboard/front corner of the center console. when the bimmini top comes up the front top of the bimmini just touches the antenna, plus the antenna has some flexibility. it can always remain up and does not cause any problems with fishing as for all practicale purposes it is part of the center console. I hope this helps.

posted 12-06-2003 08:26 AM ET (US)            

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Swell-

Birdsall Marine makes "grommets" for the fabric of tee tops and biminis that you can install and then poke an antenna(s) or fishing rod(s) up through - another option...

kf

posted 12-06-2003 01:54 PM ET (US)            

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swell

I have an 8ft fiberglass and transmitted a weak but readable signal 30nm on friday to a coastgaurd station. could not even hear them on the icom m21 handheld. bigger is better. the 8ft is mounted on an A frame over the outboard.

chris

posted 12-06-2003 02:22 PM ET (US)            

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Here's a handy line of sight calculator. Use the center of your antenna for the first station. For example, if you have a 8' antenna 5' off the waterline, use 9 feet.

http://www.vwlowen.demon.co.uk/java/horizon.htm

This will show you the effect of your antenna height.

--
Moe

posted 12-06-2003 04:14 PM ET (US)            

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Pat-

Unless my old eyes have really gotten bad, I suddenly realized I haven't seen the most obvious (and very typical) solution: mount an 8' antenna on the top frame of your T-top with a ratchet mount somewhere so you can drop it at will and duck the cable inside a leg as soon as possible for appearance and protection.

kf

posted 12-06-2003 04:21 PM ET (US)            

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Swell*** - I haven't read all of the other messages - so if I am repeating someone - my apologies. Antenna selection presents just another trade-off for the boat owner. Performance of an antenna generally improves with heigth - so an 8 foot antenna would perform better than a 3 or 4 foot. And performance is increased by mounting as high on the boat as possible. One item that many don't consider is that the Coast Guard antennas are generally mounted on high places - which reduces the emphasis of heigth on the boat.

Now - there are qualifications and trade-offs - that is, the shorter antenna emits a more omnidirectional pattern that a longer antenna. This means that on a boat where there is no rocking and pitching, the longer the antenna theory works well. On a boat where there is some rocking and pitching - such as my 17 Outrage on a coastal inlet - the omnidirectional antenna is preferred - even though the signal strength is decreased. ---- Jerry/Idaho

posted 12-06-2003 04:51 PM ET (US)            

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Vertically polarized single-element antennas are, by nature, omni-directional (assuming no adjacent objects acting as reflectors or directors). The radiation pattern is shaped like a slightly-flattened doughnut with a tiny hole in the center. Gain antennas just flatten the doughnut and increase its diameter (range for the same signal strength). 3db some, 6db more. This slight flattening isn't as significant an issue in a pitching and rolling boat, but it really is on a sailboat heeled over running with the wind abeam.

An 8' antenna has a center 2' higher than a 4' antenna, but more importantly, it's usually two half or 5/8 wave antennas stacked on top of each other. I would never claim a 4' antenna is better than an 8' antenna, even in heavy seas, unless using an 8' antenna meant mounting it low with interfering objects on the same level.

In answer to the first question, the top of the windscreen railing is probably the best operational antenna mounting location on a CC, except for the problem of the bimini.

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Moe