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Old 27 February 2007, 15:15   #1
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Rib Raider aerial

Done a bit of a search and despite the fact they seem to fall to bits the Rib Raider aerials seem to be popular, I want something fairly small as otherwise I don't stand a hope of getting it posted here and arriving in one piece, according to one site they are only 57cm long which sounds good.

Anything else I should consider? The Raider is a bit under 50 quid from Mailspeed Marine. As I won't be refitting an A frame in the foreseeable future I will probably make a "mast" either from the transom or more likely behind the passenger jockey seat, so I don't want anything big and heavy as otherwise I'll need a bigger mast!

Ta

Stephen
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Old 27 February 2007, 18:11   #2
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I think for a RIB the Raider is the best compromise. I did the same kind of research as you and came to the conclusion that a GRP whip will be more likely to break than the RAdier and the small stubby time of antenna would be useless on a RIB due to mounting height.

So far so good and almost all RIB's in the yard have Radiers fitted to them so they can't be too bad I guess.

V-Tronix claim the gain to be as good as a std whip (i have my doubts) but it does seem to work pretty well.
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Old 28 February 2007, 01:26   #3
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Whilst we do provide a lot of the V Tronix Raider antennas to RIB owners we have also found the Pacific 6106 a useful alternative, it has a variety of optional cable/mount kits and is particularly good if you have nowhere else to mount it but ontop of a console, for instance, it is extremely robust and very flexible - its also cheaper than the V Tronix

details can be found at the following web address

http://www.pacificaerials.co.nz/marine/p6106-SMPVHA.htm
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Old 28 February 2007, 07:08   #4
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It gives the gain as:

Gain 1.2dBi
"Marine Gain" 2.4dB

Anyone know what Marine Gain is?
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Old 28 February 2007, 08:23   #5
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VHF Aerial

Don't go for an aerial with a high gain. The higher the gain, the 'flatter' the coverage. With a rib bouncing around, a low gain will give better coverage.

Whilst I haven't done it, I recently talked to a dealer who advocated fitting a stubby antenna inside the conslole. He felt this gave good performance and was secure and robust, hence less likely to let you down. Admittedley, he was in the Solent so range was probably not foremost in his mind.

I have fitted two antennas just in case! And it looks good!
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Old 28 February 2007, 10:10   #6
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Quote:
Originally Posted by jwalker View Post
Anyone know what Marine Gain is?
yus. itts wen a bote deeler fils iz pokkits wiv cassh arfter sellin yew a rowpy owld ribb



WOT MAREEN GAYN IZ FOR DAT NOBBUR WJ'S BENNYFIT

gaRf
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Old 28 February 2007, 11:42   #7
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So, I've got to be careful not to compare my apples to pears!

Thanks Garfie.
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Old 28 February 2007, 14:00   #8
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Unity gain aerials used on yachts.The signal is radiated in a broad arc to compensate for the roll of the yacht.

High Gain Aerials are used on motor boats that remain more or less upright. The signal is radiated in a tight band at approx right angles to the antenna. Trouble is when it gets rough and they start to roll around and the antenna moves around abit you can get fluctuation on the radio signal an effect known as flutter.The Vtronic is I guess a hybrid suited for ribs .
When Jon Brooks comes along am sure he will answer in more detail.

Marine gain = what Garfie said
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Old 28 February 2007, 16:16   #9
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Originally Posted by JABS View Post
Don't go for an aerial with a high gain. The higher the gain, the 'flatter' the coverage. With a rib bouncing around, a low gain will give better coverage.

Whilst I haven't done it, I recently talked to a dealer who advocated fitting a stubby antenna inside the conslole. He felt this gave good performance and was secure and robust, hence less likely to let you down. Admittedley, he was in the Solent so range was probably not foremost in his mind.

I have fitted two antennas just in case! And it looks good!
VHF is pretty much line of sight so surely you want the aerial as high as possible to avoid droput when you're in a wave trough?

The way I understand thw way the gain affects the waveform is that at 0db the antenna will radiate pretty much all directions. As gain increases, the radio waves travel more perpindicular to antenna. As has been already pointed out, powerboat antennas are usually long and high gain (9db) with very flat transmission. Yacht antennas are usually 3db and quite a bulbous tx field (RIB Antennas are pretty similar to yacht in terms of pattern but a yacht will have much higher range due tot he fact the antenna is on top of the mast)

The raider does seem to work well from what I've experienced so far.
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Old 29 March 2007, 11:45   #10
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OK I now have my Rib Raider ready to fit on "something" (exact location yet to be decided)

Various people have suggested that these things have a tendency to fall to bits ... so whereabouts do they come loose and which bit falls over the blunt end? I might be able to do some preventative maintenance, at the wrong side of 60 quid inc postage, I don't want to be changing it too often

Thanks

Stephen
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