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Old 09 October 2014, 17:34   #1
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Suggest me a small boat aerial solution

OK - so I finally got round to getting a fixed VHF radio for my wee (3.9m) boat when a bargain popped up here this week.

I'm now going to need an aerial. My limited knowledge tells me (i) height will be the most important thing (ii) a high gain is OK on a powerboat. (iii) IIRC it would be better to raise the base of the aerial rather than just use a taller one?

I don't have (and am not going to add) an a-frame. I have a small (50cm?) removable light pole for my all round white light which is mounted on top of the console. Console is quite cluttered already though.

So what nice solutions have the small rib/sib people come up with for fixed VHF antennae. What's the preferred aerial? Is something like the Metz a good solution? How do people mount it?

Bear in mind that I am true to all stereotypes of Scotsmen and therefore mean and hamfisted!
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Old 09 October 2014, 18:36   #2
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baseball cap with Velcro on top and Velcro on base of antenna ! long cable ish stand up for better reception... sorted

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Old 09 October 2014, 18:49   #3
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Originally Posted by SPR View Post
baseball cap with Velcro on top and Velcro on base of antenna ! long cable ish stand up for better reception... sorted
If the cap fits...!

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Old 09 October 2014, 18:53   #4
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add antenna to poormans gecko ....



ideal solution poly !
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Old 09 October 2014, 19:04   #5
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Thanks guys ;-)

It seems Andy beat you to it though: http://cdn.rib.net/forum/attachment....2&d=1321661565
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Old 09 October 2014, 19:06   #6
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lol - you did say you were tight!

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Old 09 October 2014, 19:41   #7
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i would consider - using a s/s core fibre glass antenna bolted to transom. maybe with extension pole.

do the maths and make the choice is the extra metre "worth" it....

VHF Transmitting and receiving distances

The distance to the horizon in miles is 2.2 times the square root of the height of antenna in metres. For example an antenna on top of a 9m mast would have arrange to the horizon of...

2.2 x square route of 9 = 2.2 x 3 = 6.6 miles

If the shore antenna was 100m high then...

2.2 x square route of 100 = 2.2 x 10 = 22 miles

Total range would be 6.6 + 22 = 28.6 miles.

In practice the radio horizon is slightly more than the visible horizon - so add say 10% - 28.6 + 2.9 = 31.5 miles (i.e. between 30 to 35 miles)
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Old 09 October 2014, 19:59   #8
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As you say go high! A cool ss fat light pole with a massive VHF arial on top would be just the job
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Old 09 October 2014, 22:42   #9
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Where are you going to mount your VHF?

I run a 5225XT Shakespeare antenna, mounted to the transom. Works pretty good in my small boat. There is a mount that can fold it right into the boat so it is safe.
5225-XT | Shakespeare Electronic Products Group
Style 4187-HD | Shakespeare Electronic Products Group

You can see part of the antenna on the port side.


Folded into boat. (Your boat might be a little short for an 8' antenna, so take measurements.)
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Old 09 October 2014, 23:44   #10
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I think you need to get *something* mounted, rather than worry too much about optimum performance. VHF doesn't have a really great range in any case (line of sight for the most part), so getting the radiating element another foot or two higher isn't going to gain all that much.

I understand the whole higher is better thing, but having an OK performing VHF is better than having one sitting in the garage for trying to figure out where to put it.

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