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  #1  
Old 10-30-2009
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A more modern approach to SSB installation?

I hate to bring up an issue which has invoked so much discussion already but I have done my research and discovered conflicting statements from several sources.
When we purchased our 40ft sloop we removed the mess that supposedly served as the counterpoise for the SSB. Now that I'm reinstalling the SSB I'm not convinced that the foil capacitor solution is the most practical. For one I hate clutter, however I also can't stand things that don't work. Secondly, our hull is over an inch and a half of hand laid fiberglass (not all Newport's were poorly built bargain racers). I'm concerned that the thickness of the dielectric (the hull) could negate the effectiveness of the system as a capacitor.
As an alternative I am considering using the lighting grounding strip or a second bronze grounding strip closer to the tuner. While reading Nigel Calder's wonderful book I came across a reference to Californian SSB enthusiast Gordon West's experiments. His research suggest that even the smallest immersed grounding plane (a single bronze through hull) is better than a foil capacitor of the size that can be fitted on a boat. The article can be found in SAIL magazine October 2001. This research also suggests that the sintered bronze ground shoes that are sold commercially are a waste of money, not performing any better than solid bronze of the some dimensions. Furthermore, various marine life grows not only on the surface where it could be removed, but also within the bronze matrix where it cannot be removed.
I would like to hear back form anyone out there that is using a solid bronze ground of any size, whether it's a single through hull or a large bronze plate. I would also appreciate someone setting me straight if my logic is flawed. Otherwise I think I'll go ahead with a piece of solid bronze flat bar near the mast for my lighting protection and another near the tuner for the SSB.

As an afterthought I realize there is something fundamentally wrong with my understanding of a foil capacitor system. From what I have read you can have a foil capacitor and an immersed ground. I thought the whole point of a capacitor was to have the two halves separated by a dielectric. Can someone explain what I'm missing here?

Last edited by Newport41; 10-30-2009 at 04:09 PM.
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Old 10-30-2009
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Don't know about the dielectric issue; but when it comes to "ground plane" there is no better ground plane than the ocean. So whether you use a solid bronze bar, a sintered bar or a thru-hull; you should be getting a better ground plane than a copper foil in your bilge. That's how my boat is setup also; and I do plan to switch to an external ground.

The problem with running the ground to a thru-hull is the issue of stray current and degradation of the thru-hull. I would rather use a dedicated plate with smaller fasteners through the hull so that the fasteners would not cause such a fast flood should there be a failure.

On the issue of the sintered shoe; it's just to maximize wetted surface area; and of course you will get growth covering most of the external and internal surfaces; but the same is true for a solid plate it will just happen much more quickly. It would be interesting if you could make a mount on the hull so the plate could be removed and soaked in acid now and then to dissolve off the growth and restore ground performance.

You should join us over on the newport owner's forum; go to the capitalyachts website and then click the yahoo groups link:

Newport, Neptune, Gulf sailboats built by Capital Yachts

-Russ
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Old 10-30-2009
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Quote:
Originally Posted by KeelHaulin View Post
Don't know about the dielectric issue; but when it comes to "ground plane" there is no better ground plane than the ocean. So whether you use a solid bronze bar, a sintered bar or a thru-hull; you should be getting a better ground plane than a copper foil in your bilge.
-Russ
Agreed. I have attempted to follow some of the discussion on this issue and have come to the conclusion these folks are putting FAR too much effort into all of this. My feelings are just charge up your backstay with the center conductor and drop a wire in the water for the ground plane and all will be fine. Of course you will need a tuner. AFAIC audio is more important than signal. All of this that and the other is going to make a neglible difference in your signal. Good grief! A couple of dB at best is my assessment. I'm sure others will quickly try to put me in my place regarding this, but I'm quite certain the most gallant efforts to put out a big signal will not be noticed by the average user who just wants to make contact with the net for the sake of making a contact. It really takes very little for an HF signal to get out. I've done it by laying a long-wire on the ground. And come on, a $125 Shakespeare or $30 Hamstick with a proper ground-plane will do more than most of this effort I've seen discussed here. Good luck!

No offense to anyone here. Have fun dorking with your rig. I have for forty years and found that nothing beats a piece of wire strung across your "backyard".
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Last edited by nuffoftexas; 10-30-2009 at 05:08 PM. Reason: Pulled the HAM radio recommendation
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Old 10-31-2009
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Newport21,

Probably not telling you anything you didn't already know with this, but ...

Your SSB is kind of like an electronic pump that vibrates energy into the air (and out of the ground), and then into the ground (and out of the air), that's probably the easiest way to think of it. The "into the air" part is the antenna, and you want an antenna that couples well to the sky, some antennas work better than others. The "into the ground" part is your ground plane, and again, you want it to connect well with the earth. If either half of that system isn't good then the other half isn't any good either, so you can have a great ground plane and a lousy antenna and it won't work well, and you can have a great antenna and a lousy ground plane and it won't work well, and the only way to get a really good system is to have both a good antenna and a good ground plane.

To couple well with the earth (or water) what you are trying to do is spread out from the radio with a lot of conductive material so that the RF energy can move easily to and from the earth. On land you'd often do that by running radials out in all directions from your radio over a wide area so that you have kind of the least resistance possible so the radio wouldn't have to work very hard to pump energy into and out of the ground. RF energy is weird in that it doesn't really have to conduct, exactly, it is more of an alternating type of current, and that is why the capacitor method on the boat works, because you're essentially building half of the capacitor in the boat and the ocean becomes the other side of it, and the large surface area makes the energy move easily.

I don't know how much that helps you, like I said, probably nothing you didn't already know.
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I am putting an ssb on my boat this winter. I talked to the electronics guy at the boatyard to see what he thought since he has installed literally dozens of ssb systems in boats over the years. His opinion was that all of the miles of foil and netting inside the boat is a waste of time - He thought the thing to do is to get a bronze plate on the bottom of the boat - He said dynaplates are good but it really doesnt much matter so long as you have a large piece of metal with good electrical contact. My first idea was to use a bronze through hull with capacitors in the connection to eliminate the problem of electrolysis. He said that would work but would have far less surface area than a bronze plate would have. OK if you dont want to haul the boat to get it done but if you are going to have the boat out of the water anyway it is worth it to put a plate of some kind on. Either way you are going to have to put a mask on occasionally and scrub off whatever is growing on it.

I believe this guy not only because he is a sailor himself but because he has done this lots of times and would have had unhappy customers making him redo it if his method didnt work.

Hope this helps - I will find out if it works myself after I get the boat back in the water next spring.

One more thought - He said installations are VERY sensitive to having good connectors and proper wires. It seemed that he thought that was more important to get right than what shape the piece of metal in the water is.

Last edited by sck5; 10-31-2009 at 09:46 AM.
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The electronics guy at the boatyard has it right. Mostly.

I, too, have done dozens of installations -- do it for a living these days. And, each installation is tested on-the-air with the owner present, and most are tested on nets in the days and weeks following the installation as the boat moves north or south.

I did a piece several years ago, published on the SSCA Board, on "RF Grounds in the Marine Environment". Believe that is still valid.

As Gordon West found in his tests, a length of copper stripping from the tuner to the nearest bronze thru-hull will serve as a pretty good ground for most boats. It can be improved, somewhat, by adding radials, bronze plates, etc. But the improvement is often minimal.

Most important is to get a good, clean installation with very tight connections and adequate power to the radio. Keep everything separate from other onboard systems, particularly the boat's AC and DC grounds, lightning grounds, engine, etc.

Many tuners have a capacitor built-into the DC ground circuit, so there's no problem with electrolysis.

The role of seawater as a "ground" is very widely misunderstood, as is the purpose of coupling to it. One of the most beneficial reasons for coupling to seawater is noise reduction...bleeding off static and reducing RFI both ways...from the radio to other instruments, and from other instruments to the radio.

Seawater is an excellent reflector of RF energy. It is a horrible conductor of RF at the HF frequencies used for marine SSB. Signals are attenuated greatly in just a few inches of seawater. Thus, the idea is to bounce signals off the water, not to feed them deep into the water where they will serve only to warm the seawater!

In this regard, it's perfectly possible to construct a good RF ground which doesn't couple directly to seawater at all. This can be done using radials under the deck, s/s rubrails, aluminum toerails, pushpit/pulpit/lifeline complex, big radar arches, and any number of other solutions.

And, of course, the most effective long-distance antenna of all -- the single-band vertical dipole (a balanced, resonant wire antenna) -- works completely independent of any external RF ground.

So, what's the bottom line?

1. By all means, run a 3-4" wide heavy (16oz) soft copper strip from the tuner ground lug to the nearest bronze thru-hull. This will provide a good basic ground and will help reduce noise.

2. If you're so inclined, try adding to the ground....radials, or any of the other ways mentioned above. Often, this isn't necessary.

3. Be sure your antenna is at least 23' long overall (counting from the antenna lug on the tuner)....around 40' is optimal for both low and high band coverage.

4. Be sure your connections are top-notch. Use high quality crimpers, connectors, and adhesive heat-shrink. Pay close attention to the GTO-15 connection to the backstay.

5. Be sure to provide adequate power to the radio. Use AWG6 cabling, minimum, directly to the batteries. Mount a 30A fuse in both the positive and negative wires, close to the batteries.

Do these things and you'll have a good SSB installation.

Bill
WA6CCA

Last edited by btrayfors; 10-31-2009 at 10:27 AM.
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Originally Posted by btrayfors View Post
And, of course, the most effective long-distance antenna of all -- the single-band vertical dipole (a balanced, resonant wire antenna) -- works completely independent of any external RF ground.
I learned something new! With btrayfors posts that is always the case!
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Thanks for the input. We are on the hard next week and I think I well go ahead with an external bronze plate. And cruising in the tropics will make cleaning the plate from time to time not nearly the ordeal it would be here in BC. As I suspected this whole issue of SSB installation has, like everything else in the marine world, been made out to be way more complicated than in is. Thanks for the input.
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Old 01-24-2010
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ssb antenna

having spoken to numerous persons i consider knowledgeable by virtue of their experience in the matter i have surmised that a perfectly adequate ssb antenna can be made by simply placing a 40' +/- stranded copper wire from the mast top to the transom to the radio accompanied by a ground wire to ground shoes, etc. just purchased a grundig satellit 750 as a backup & in the manual they suggest a very similar setup. can anyone comment for or against this idea? seems like a k.i.s.s. idea to me. jim
s/v mello moon

Last edited by westerly84; 01-24-2010 at 11:53 AM.
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Old 01-24-2010
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The bronze plate thing will always work...any time, anywhere. It is not the most elegant solution to the ground problem, but it is the most trouble free and performance predictable.

Racers abhor plates or bars that interfere with their slick bottoms, so a through hull looks more and more attractive, given that they're not inclined to experiment with radials either.

If you like the idea of plates, Dyna or otherwise, be aware that there is no discernable performance difference between the "sintered" variety or solid except that you'll pay more for the marketing hype...surface area is not materially improved by sintering... in this application, anyway. Further, marine growth does not electrically insulate either one, just a normal brushing when the bottom is cleaned is sufficient. Don't paint it though.
Howard Keiper
Berkeley
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