Maritime "earthing" SSB radios

[ZS6FB]

Hi Everyone.

I am about to install an Icom IC 706 into my Catamaran (35 foot) and I need advice on earthing. It seems guys go to a lot of trouble to install external and internal earths, but why can one not just connect the rig to the Saildrive (or both sail drives). Is there an electrolysis issue?. Where is the problem?

If you can reply to me directly on my e-mail (bheasman@gmail.com) as well as in this forum I would be grateful. I am sure there are others who would like to know the answer to this riddle.

Kind regards.

Bob ZS6FB

[DeepFrz]

by "Earthing" I suppose you mean a counterpoise. There have been many threads and posts on this and other forums. One of the easiest ways of creating a counterpoise is to connect the "ground" output of your tuner to your aluminum toe rails or your lifelines. Barring that, run some radials above the waterline under your deck or along the inside of your hull. Just keep them away from other cable runs so as to not induce rf into your other electronic equipment.

Bill Trayfors has posted information and links on his vertical dipoles that require no counterpoise, and no tuner. These are probably the easiest and simplest ways of ensuring good rf transmission.

[ZS6FB]

Hi Deepfrz,

Yeah, I have read about that method as well as a few others, so thanks for your trouble.

But I really would like to know what is wrong with my idea of using my sail drives. I take one wire from the antenna base and fix it under one bolt., it is done. Nice, simple, quick and easy. The surface area is also huge.

Bob ZS6FB

[DeepFrz]

Bob, let us know how it works.

[Paul Elliott]

Bob,

Some people get decent results with just a single through-hull connected as the R.F. ground, and I think that using the saildrive as a ground will probably do a pretty good job. You should review the connections to all your underwater metal, to make sure that you are protected against electrolysis (and other electrical problems).

Definitely look at the discussions here to see what antenna systems other people are using, and why. It isn't really voodoo, but some times it might as well be because of all the variables. You can probably put together a better ground system, but remember that whatever you do will be a compromise of some sort. Some times "good enough is perfect", if it gets you where you need to go.

Be sure to test it ahead of time on all frequencies you want to use.

-Paul - wb6cxc