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Old 29-08-2008, 07:35   #31
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Motorized antennas

Here is one, I think these are a bit pricey. They may be other les expensive solutions out there:

Hi-Q Military Antennas - Shipboard Antennas

Chris

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witzgall
Don't know what you mean by a screw type antenna.
I haven't researched any as yet, I am only trying to decide on what I will do for the ground side. So many strong differing opinions to connect to water or avoid it. I will be using a whip of some sort. Not the time to experiment with the mast.
I have decided to pull some radials into the stiffening tubes under my bridgedeck and to put some mesh on the bridgedeck as well. I will also put in some copper foil down to where I would put a bronze plate through the hull. This way if the radials/mesh are no good I can add a water connection quite easily. Now just need to find out how much mesh to use. I am thinking of about 3 square meters.

Mike
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Old 29-08-2008, 09:44   #32
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I've been thinking about my suggestion for a glassed-on wire or tape on a carbon mast and have decided it's a bad idea. Lightning will vaporize that wire or tape, igniting the mast at that highly focal location. This is a frightning picture. I investigated a very few carbon fiber experimental aircraft accidents and the charred structures were extremely hazardous.
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Old 30-09-2008, 17:05   #33
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I am in a similar predicament as Mike in the installation of a SSB radio in a cat I am building. I have purchased an Icom M802 with auto tuner and intend using one of the inner shrouds as the antenna, with insulators as it will cost about the same as an separate whip antenna.
As with Mike I have no through hull fittings to connect the ground to and not a lot of room to run a copper ground within the hull so had intended using an external ground plate.
Is a ground plate an alternative or should I abandone that idea altogether and try for an internal copper ground?
Second point, is tinned copper braid (25 mm wide) sufficient to run from the radio to ground to tuner, or should I use copper tape?

Mike, if you have not already purchased a SSB radio, I can put you in touch with an Australian company that provides the best deals on this equipment.

Peter
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Old 30-09-2008, 17:52   #34
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As one of the earlier posts suggested, when talking about grounds, it is not the mass of the ground, nor the visual area, but the actual surface area that makes the difference. This is why the last post, suggesting the tinned copper braid, is to me the winner regarding the grounding issue. The woven braid has much more surface area than any strip of copper or most of the other suggestions. I took ~15 feet of it and ran it under the floorboards of my cat, and connected it to my tuner. It really works just fine.
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Old 04-10-2008, 00:06   #35
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Originally Posted by spiritcat View Post
.....
Second point, is tinned copper braid (25 mm wide) sufficient to run from the radio to ground to tuner, or should I use copper tape?
........

Peter
Peter,

I suggest copper tape at least 50 mm wide. In my experience it has a much lower impedance at HF frequencies than similar sized copper braid. My some what limited RF knowledge tends to support this view.

BTW, can you PM me with details of the Aussie company you referred to.

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As one of the earlier posts suggested, when talking about grounds, it is not the mass of the ground, nor the visual area, but the actual surface area that makes the difference. This is why the last post, suggesting the tinned copper braid, is to me the winner regarding the grounding issue. The woven braid has much more surface area than any strip of copper or most of the other suggestions. I took ~15 feet of it and ran it under the floorboards of my cat, and connected it to my tuner. It really works just fine.
Sono,
I can't comment on using TC braid as ground in itself as I haven't tried it or know anyone who has but I would caution against using it as a low impedance RF conductor to an existing ground. My experience suggests that it has a higher inductance than equivalent copper strip.

It would be an interesting experiment to try both (as a ground - side by side) in the same installation and compare the results.

My 2 cents worth
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