SSB grounding...

[Amadis]

I am about to install a recently purchased 2nd hand Icom - M710 onto my wooden yacht. I was planning to ground the tranciever and ATU to the lead keel via keel bolts. Having chatted to a marine electronic engineer he has advised me that a more effective ground can be achived by connecting to a copper strip attached between two through-bolted 2"x6" metal plates (one each side of hull below waterline). This ground would be much closer to the ATU than the keel bolts.

I have never heard of this technique however - there is much conflicting advice regarding SSB installation!

I would be grateful to hear from anyone who has used this method for grounding and any comments before I start drilling holes in the hull!

Cheers.

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[Deleted member 478]

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[Talbot]

2 x 6" is a bit on the small side for best results at lower frequencies (e.g. 2182) Just about anything will work, the difference between good and bad is the range that you will get at the frequencies you want to transmit at. seek advice from a number of the specialist shops, and then combine the responses!

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[jerryat]

Hi Amadis!

Go with your original thoughts. Taking a 75mm wide copper foil strip from the ground on your ATU (automatic tuning unit) to the keel bolts will give you an excellent counterpoise (ground). The distance does not matter as the foil itself also provides part of the grounding system. Try to ensure that the foil is either painted, or fitted such that it is clear of any bilge water as this will corrode it fast enough to seriously affect performance.

The foil may be fitted in any plane i.e. against a vertical engine bay panel. Orientation has no effect on performance. I fitted part lengths of mine by using impact adhesive and gluing it into place, followed by painting or coating in grease (where painting was not possible) and this has survived intact for nearly six years and many thousands of miles.

Basically, and in simple terms, the bigger area of 'contact' you can offer to the sea, the better.

Hope this helps,

Good sailing!

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[snowleopard]

icom will send you a wad of paper on the subject if you give them a call.

the key points are that you must use copper strip to connect the ATU to ground, even massive wire isn't enough.

if you use a ground plate it should be sintered bronze which gives a large contact area, e.g. 4" x 10" gives about 1.5 sq m

the earth plate does not have to be in physical contact with the water so a mesh on the inside of the hull will do the job, the connection is made by capacitance.

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[BigART]

This is a very useful link:
<A target="_blank" HREF=http://link> http://www.icomamerica.com/support/documents/antena_grounding.pdf </A>


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[trouville]

im amazed at the rubbish posted in general. but hear to talk of copper this and that...umm just buy a proper transmitter earth it looks like a gold bar there are different sizes but a 10by 4 inch ought to do i use one for my 200watt TX and neve mesured nor had a problem with the keel falling off or fittings droping out due to the current and differeent metals such as copper and iron and brass and even plastic which becomes brittle!! on plastic boat with lots off current leak

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[Breoch]

Gave us a 100% improvement in reception. It is the "correct" way to do it. Infact you can purchase special anodes that are wafer/folded construction to increase the contact area, but the metal plate you describe will be adequate.

If still not sure, make a temporary connection to one of your anodes and see the difference.

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