Monday, March 14, 2011

On being well-grounded

Maintaining a good ground for your SSB without compromising your DC grounding system and thereby causing electrolytic or galvanic corrosion is not easy. But Livia on s/v Estrellita 5.10B makes it look that way. This is a well-thought out solution to that problem
IMG_5456 (1280x853)When we finished our SSB installation in the Polkinghorne Islands, we ran copper foil from our tuner to a single thru-hull. (Pretorien owners, this is the sink drain.) We’ve been checking in on the nets, getting weather and checking email for the last 6 months or so with the copper just draped over the thru hull--->

Our water tanks were already connected to this thru hull with copper wire so we also have our water tanks in the mix.

We decided to start with a minimal ground plane installation and if that didn’t work well enough, add more. We initially did some simple testing of the system and found that we were heard better with both the water tanks and the thru hull than just the thru hull but with just the thru hull we were consistently being heard and connecting to email/weather via winlink.

Even though our tuner (Icom AH-4) has some built in current protection, to further protect from any stray current eating at our thru hull, since the install, we have had to open up the floor panel and manually connect and then remove the foil from the thru hull so it wasn’t touching when we weren’t using the SSB.
Recently, we finished the installation by permanently connecting the foil to the thru hull with some .15 microfarad capacitors as blocks for stray current.

Here we have my tools set out. SV Endless, I promise I am eventually returning your solder iron!

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Here you can see the pipe cuff that was already installed for the water tank wire (to make contact with the thru hull). Using the screw holes as a template I folded the foil over several times and then drilled holes through the folded copper foil to match.

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Finally, I glued the foil to a bit of starboard with a clean gap (no glue or anything bridging the gap) and soldered the capacitors to the foil. My soldering skills remain laughable but so far, everything I’ve soldered still works so I’m calling that a victory.

Here you can see the final installation with the copper wire that goes to a foils strap on our water tanks.

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We’ve now had a chance to test the installation and it works. The problem with an SSB is that the only way we know how to test it is functionally: it works if people can hear us, if we can hear people and if we can regularly connect to winlink stations. A complication is that propagation makes all contacts vary and recently there were a bunch of solar flares.

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