SSB - Online resources for a newbie?

jerryat

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Joined
20 Mar 2004
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3,569
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Nr Plymouth
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Hi chibb !

Benbow beat me to it and is absolutely correct. A steel boat offers the perfect counterpoise so, as he says, a good (75mm) wide copper tape connected to your ATU/Radio and bolted to a nearby convenient place on the hull would be fantastic!!

Cheers Jerry
 

PaulJ

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Joined
7 Jul 2001
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695
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Ipswich
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Chibb, I have used a "capacitive earth strap" details of which are on the Sailmail website. Because there is a bunch of capacitors in the earth strap, it grounds at radio frequencies but does not allow 12Vdc to pass. As Benbow says, the hull itself is a fantastic ground. I have not grounded the Transceiver, only the ATU, though I have to confess that I suspect there is some stray RF flying around, particularly at the low end of the spectrum. It may be that I also need to earth the transceiver but I will wait until the boat is in the water with the mast up before probing into that further.

It is worth noting that you connect the Transceiver to the ATU with co-ax cable, that does not radiate and can be pretty much any length but everything downstream of the ATU does radiate and must be considered as part of the antenna. That means that the bit of wire that connects the ATU to the backstay also counts as part of the antenna and should therefore be as short as possible. On my boat I have mounted the ATU at the back of and within the coaming around the cockpit and the wire connecting it to the backstay will only be about 2ft long. The earthing strap goes from the ATU to a stud I have welded into the cockpit coaming and is just a few inches long.

The Sailmail website is www.sailmail.com and details of the capacitive earth strap will be found by clicking on "Sailmail Primer" then "Application Notes" and then "Grounding Tips".

This should take you straight to it www.sailmail.com/grounds.htm but I strongly suggest that you read the rest of the stuff in "Sailmail Primer" because there is a lot of very good information in it.

Paul.

Thanks must go to Ship's Cat who pointed me to the capacitive earth strap in the first place.....
 
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