jeff,
i believe you need a 100 sq foot counterpoise consisting of copper foil. dynaplate is a good ground but will not suffice. its a ***** adding all the copper but it is necessary. mc master carr has nice wide THICK copper for this job.
what radio did you buy?
eric

 

Dear Cap''n Jeff,

From the east cost of the United States, we routinely talk via our SSB with cruising friends in Europe, Central America and South America. For our ground plane, we use a Newmar Ground Shoe, size 6x18. This type of ground equates 100 sq/ft of copoer and foil laid throughout your hull. When checking in to various cruiser''s nets, we are repeatedly told that we have a very strong signal.
Recently we spoke personally with Gordon West rearding this type of ground, and he concurred that all that copper strapping was no longer necessary with modern-day equipment.
So, based on our experience, we encourage you not to bother with all that copper. Drill those holes in your hull, it ain''t so bad, and install a dynaplate. You''ll be glad you did.

Regards,

Sue and Larry

 

be sure to attach the dynaplate as close to the tuner as possible--also attach your water/fuel tanks with copper foil to the ground system--i''ve done both and have an excellent signal, tmc

 

Hi, Jeff...

Here''s a specific answer to your question & also some differing opinion from what you''ve already received:
1. We were forced to rely primarily on a Dynaplate for our counterpoise on a previous boat. We too got consistently good signal reports but that often means little (see below) and I''m sure that we could have had better xmit performance if we''d access to more mass below. So...it will work but isn''t THE answer.
2. Newmar usually makes good stuff, and perhaps the ''shoe'' is comparable to a Dynaplate, but most likely not ''the'' answer, either.
3. Signal reports for one install method are - regretably - a terrible way to determine how to install your system. This doesn''t have to do with the honesty of the reporter, but rather the typically poor form of signal reports offered on Marine SSB. (I''ve yet to hear one Marine SSB user give a report based on the one common baseline method - RST - that''s in use, so who knows what ''good'' is?) Ham operators are usually better about this only because they tend (at least in some cases) to know something about radio operation & procedure. So...my point is that its tough to know which choices to make based on what I or someone else will tell you about how great our radio works. (OTOH, I have a GREAT radio installation...!<g>)
4. Here''s the approach I''d recommend for your counterpoise. Start simple, running 4" or wider foil (sold by the foot by Defender; good price) in the bilge from the tuner, forward to whatever largest metal mass(es) you can reach that are not in turn tied into your 12V negative ground. (Read each piece of that sentence, again). Don''t overlook using your lead keel, as encapsulated lead keels can often be reached by drilling a hole down thru the fiberglass cap and then using a lag screw to tie it to the foil. Be creative. E.g., one great additive source of a counterpoise are the half-oval stainless strips on rub rails. If you fell you must install a dynaplate at this point, you may not be trying hard enough. Now - after the inevitable teeth-cutting problems as you learn how to work your radio - determine with the help of multiple knowledgeable signal reports, on different days, how good your counterpoise is. Ask around: your boat may be in a bit of an rf black hole (e.g. St. Pete''s marina has this reputation; so does Satellite Beach near the USAF base); adjust its location when doing this, if you need to. Only after you''ve done this initial level of install, consider adding to your counterpoise.
5. People often confuse rf ground (counterpoise) with 12V negative ground, thinking they are essentially the same. This can lead not only to rf running all over the boat''s electrical system, squirting out in funny places, but it can seriously degrade your transmit or receive ability. I recently helped 2 boats fix huge problems caused by them diligently tying these two systems together thoroughly. That''s why I caution you to stay clear of using the engine, metal tanks (which are most likely grounded), etc., at least initially.

Good luck! You''ll no doubt find SSB adding immeasureably to your boating pleasure; the effort is worth it.

Jack Tyler

 

How the dynaplate works.

The theory is that the porus surface of the dynaplate provides a very large surface area contact with the water - many times the area of the plate itself.

The truth is that the resistance of the seawater down through the crevices is so high in comparison to the copper to seawater interface that it doesn''t provide any added advantage over a plain copper plate of the same size.

I don''t imagine that green marine growth diminishes the effectiveness very much, although barnacles may have sufficient insulation to reduce the surface area.

I believe that Practical Sailor did a test on dynaplates and found them no more effective than an equivalent copper plate.

If you have a metal keel, even if enclosed in fiberglass, this is the best and easiest ground to use.

 

Great info Jack

Jack,

If one was to keep 12volt grounding system and counterpoise separated, how would you ground the negative side of 12 volt power to the radio set? I would assume that if you used the 12 volt grounding system for power it would end up bridged to the counterpoise system via the radio. But I assume that you need use the 12 volt ground in order to complete the circuit to the batteries.

Regards,

Craig

 

This debate comes up way more often than is necessary. If you have the time and energy, and a reasonably clean area onto which you can affix the necessary foil, then by all means do it. Any of the techniques described here work. I have gotten used to laying down the foil or sheet with fiberglass carpet tape...the adhesive is unbelievable...but your hull must be clean. No diesel oil. Yes, you will get predictable results consistant with the effort you put into the installation.
Having said that, installing a Dynaplate will give comparable results. Maybe no better, but definitely no worse either. If your boat is on the hard, it is usually very easy to pick a place close to the tuner where you can connect, once again, using copper foil or sheet. BTW, get your copper in whatever form you like from a roofing supply store, not WM.

Dynaplates last virtually forever, probably longer than the boat and certainly longer than the strips laid in the bilge. Marine growth does not affect the grounding characteristics of the plate one iota, though it may make you feel better if you had it scrubbed with a wire brush when your bottom is cleaned. It is a fact that it's thickness might slow you down if you race, but not much.

I don't have a horse in this race other than I install SSB's and I don't like call backs for poor performance. The bottom line is that you can't use performance as the criterion on which you make your decision.

Howard Keiper
Berkeley

 

More great info Howard, thanks,

So do you subscribe to the practice of keeping counterpoise and 12 volt grounding separate? I can certainly see why RF leaking into the 12 volt grounding system would be a problem. Boy, building separate systems sounds like a lot of work and engineering.


Regards,

Craig

 

Hi Craig....

Yes indeed, I do.
I know it's fairly common practice to make the engine and any other convenient mass of metal below the waterline part of the counterpoise system, I just don't like to do it if other options are open.

howard keiper
Berkeley

 

There is a much easier way to get a ground. I had purchased an ICOM M802 to install on my boat. As it also does ham bands, I figured I would upgrade my license from a tech to a general to take advantage of the whole radio. When I upgraded my ham license, I took a class with Gordon West. He suggested running 4" copper foil from both the transceiver and the tuner to a bronze thru hull. I had read all literature regarding getting at least 200 square feet of ground. I thought Gordon had a few screws loose. But I figured what did I have to lose. If it didn't work, I was only out about an hour of my time. Darned if it didn't work. I'm in California and my first contact was in Indiana on 20 meters. And last weekend I talked to a ham in Argentina on 17 meters.

Give it a try. Couple of tips. Run both the tuner and the transceiver unit to the same thru hull, one that is always in the water. The one I selected was the raw water intake for the engine. Make sure the thru hull is clean, and use a hose clamp to hold the foil in place. Like I said, if it doesn't work for you, you will only be out about an hour of time.

I have an article written by Gordon West on the subject, but if you use a seach engine, you can find it on the net. I suggest using the least invasive grounds first before you install the dynaplate.

 

He suggested running 4" copper foil from both the transceiver and the tuner to a bronze thru hull.

I did exactly that and I have talked to people in California from the Cook Islands. It works really well. The copper foil runs from the radio to the tuner and then on to the thru-hull.

 

In fact, here is the article on the net:

http://www.kp44.org/ftp/SeawaterGroundingFor_HF_Radios_byGordonWest.pdf

Give it a try!

 

Very interesting article, thanks!

-craig

 

I have to admit I was skeptical of Gordon West's ideas, but it does work well for me. My signal reports are as good as my friends on the same radio. Only difference, they punched holes in their hulls for dynaplates and I didn't. I took the simpler route. I'm a big fan of fewer holes in a hull, the better.

 

Thank you for all the great info!

Please excuse my ignorance but if you run a foil from the radio to the tuner then onto the thru-haul, does that not bridge the counterpoise system with the 12volt grounding system where the radio is the common point for both?


-craig

 

Not any more than any other method of grounding. The chassis of the transceiver and the tuner end up grounded both for the antenna and for the electrical system regardless of the method. Both grounds end up connected through the seawater connection. The thru hull I use is not grounded by a wire into the electrical system.

On a boat, there are going to be compromises on every installation. For example, I have found that there was no way I could get rid of the noise caused by the inverter/charger, the fridge and the freezer. Didn't matter where I hooked up the ground or the 12 volt hot line. So I accepted it as part of the system, made my installation simple as possible, and shut off the breakers for the equipment when I'm on the radio. The fridge will stay cold long enough and I have a good battery bank to draw from.

I just make sure I have my cold drink in hand before I turn off the breakers. You got to keep your priorities in order!

 

Not any more than any other method of grounding. The chassis of the transceiver and the tuner end up grounded both for the antenna and for the electrical system regardless of the method. Both grounds end up connected through the seawater connection. The thru hull I use is not grounded by a wire into the electrical system.

On a boat, there are going to be compromises on every installation. For example, I have found that there was no way I could get rid of the noise caused by the inverter/charger, the fridge and the freezer. Didn't matter where I hooked up the ground or the 12 volt hot line. So I accepted it as part of the system, made my installation simple as possible, and shut off the breakers for the equipment when I'm on the radio. The fridge will stay cold long enough and I have a good battery bank to draw from.

I just make sure I have my cold drink in hand before I turn off the breakers. You got to keep your priorities in order!

It's important to remember that what you are creating is a counterpoise - technically speaking, not an "ground" as most folks understand the term. A counterpoise is a wire or group of wires or other conductors mounted close to ground, but insulated from ground, used to form a high capacitance, low impedance path to ground. It is an RF ground, not an electrical ground.

Most sailboats utilize an insulated backstay as a "tunable" vertical antenna. Depending on the length of the backstay and the frequency of operation, this is close to a 1/4 wavelength. Normally, one would want at least a 1/2 wavelength vertical antenna but this would be prohibitively high for the lower HF frequencies. By using a counterpoise, you effectively create a "mirror" and make the 1/4 wavelength vertical "appear" to be 1/2 wavelength.

The other reason to use an isolated counterpoise is the impracticality of installing a proper ground under your backstay vertical. An ideal ground under a vertical antenna is about 120 wires each 1/2 wavelength long mounted in a radial pattern at the base of the vertical. Ain't gonna happen on any sailboat. If you reduce the number of radials, then the length of each can also be reduced with little effect. That is, if you installed, say 10 radials there is virtually no difference between 10 of them at 1/2 wavelength long or 1/8 wavelength in length. However, the efficiency of your vertical antenna decreases dramatically with fewer radials. For eg. with only two radials (even if they're long ones) the vertical is only about 25% efficient.

By using a counterpoise, you "simulate" the effect of a perfect RF ground and can get away with a shorter vertical element (because the vertical element has a greater capacitance (more loading effect) to a counterpoise than one leg of a 1/2 wavelength radiator to the opposing leg.

BTW, if you have EMI/RFI issues on board with inverters and switching power supplies, I suggest making common-mode chokes with mix 43 ferrite "beads" or toroid cores. Properly made and placed, these are exceedingly successful in eliminating virtually all such noise sources. An excellent article on how to build and place these can be found at the link below. Follow Chuck's advice and you'll have a nice, quiet radio!

Just google "W1HIS Common Mode Chokes" to see find his article.

Cheers,
Robert
VE7BDO/VA7RZ

S/V Ansero - '89 First 405

 

There is another option - a copy of which is attached and describes how to effective isolate the Rf and Dc grounds (depending on how you install the radio).

The solution is to find a dry secure place along each of the copper RF ground tapes that are running to your engine and keel. Fasten tape securely to an insulating piece of phenolic or to a terminal strip, cut a 1/10-inch gap across the tape, and solder several 0.15uF ceramic capacitors across the gap. These capacitors will be transparent to the RF, which will be happily grounded by the ground tape system, but they will block any DC currents from running through the RF ground system, and will avoid any resulting susceptibility to hot marina electrolytic corrosion. It is worth selecting the capacitors carefully, because they may carry a significant amount of RF current.

West Marine: West Advisor

 

Don, not a bad idea. I'll have to give it a try and see if it helps any.

 

More dumb questions, please be patient with me

Ah, so why not just create a common ground with everything anyway? I didn't even think about the power for tuner, doh! It seems a lightning strike will opt to want to travel right through my (soon to be purchased radio/tuner) to the nifty ground in my through-haul seacock.

The learnings from this discussion are invaluable to me, thank you.

-craig

 

More dumb questions, please be patient with me

Ah, so why not just create a common ground with everything anyway? I didn't even think about the power for tuner, doh! It seems a lightning strike will opt to want to travel right through my (soon to be purchased radio/tuner) to the nifty ground in my through-haul seacock.

The learnings from this discussion are invaluable to me, thank you.

-craig

The nifty ground would be vaporized after a lightning strike if it chose that path... Common ground? it depends on if your boat has a bonding system or not. There are a lot of real dangers tieing everything together with the copper foil. Particularly with the engine. Do you really rant to run the risk of starting or charging current running through the foil to the radio and tuner? On the other hand your radio DC negative should be fused also, so you can reduce the chance of this scenario causing damage. I am a big fan of single point counterpoise. I tied in my lifelines too, but basically all I have is a dynaplate connected to the tuner with foil and to the radio with 1/2" copper water pipe. Works great.

 

k1vsk, just saw your post.

Wow, that is cleaver.

 

As for a good grounding system and counterpoise, we have just finished installing our SSB and have used the information and material from this chap, he has also given us great advice on checking our system, not to mentioning matching our counterpoise to our antenna. Rope Antennas, Single Side Band antennas for Sail boats, powerboats, SSB antennas
the total cost to us was about 230 dollars including shipping, well worth the investment.

 

Robert...

I understand the eloquence and elegance of your response...I really do, and I'm not intending to pick a nit. I believe however, that the original question was to the efficacy of a Dynaplate or it's variants. Do they work? Yeah, they do. Are there other, more efficient methods that don't require surgery on your boat?? Yes to that too, but the list of those that do work well at a reasonable cost diminishes rapidly. Foils, radials, encapsulated keels, Dynaplates and whatnot all have their advocates and all (or each) would seem to work well if you believe these many posts. I like to use Dynaplates or shoes. That happens to be my method of choice...not elegant, maybe, but they work...all the time
I understand the theory and the concept, too, but what it comes down to is_ when I'm in south Bora Bora and I want to chat with someone in Whidbey Island, can I do it?
Howard Keiper
Berkeley

 

Howard,

If you were in south Bora Bora and wanted to talk with someone in Whidbey Island, you'd be much better served by a vertical dipole operating on 20 meters (or one cut for the 12 or 16mHz marine band if desired). Much better for long-distance comms than ANY backstay/RF ground/groundplate/counterpoise solution

Still, your point is a good one. On some boats, ground plates DO make sense. Readers who know me won't believe this, but I actually specified one -- a bronze plate -- for one of my clients, since there was no other practical solution. He's now in the Bahamas and I hear him regularly.

However, for MOST boats a ground plate isn't necessary. Nor is tying into the keel or the water heater or whatever. Many boats lend themselves to using a simple radial consisting of a stainless rub rail, an aluminum toe rail, the pushpit/pulpit/lifelines complex, or other above-the-water RF radial system. There is no need to "couple to the seawater" in order to have a good transmitted signal. This is a very persistent myth which has haunted most discussions and most texts and many user manuals for decades. It's just pure bunk. Any experienced ham or radio transmission engineer knows that radials work very well, and that elevated (above-the-ground) radials work better than those on the ground or buried beneath the surface.

That said, there ARE reasons to connect directly to seawater, in addition to having a radial ground for RF, including bleeding off static electricity and making for quieter reception. Nothing elegant is required: a simple ground strap to the nearest bronze thru-hull is sufficient.

IMHO,

Bill
WA6CCA

 

Having Marelon thru hulls meant using a dynaplate on my boat. tied the water tanks in with foil for good measure. Seems to work great with the Icom 802. Seems to me that this is another area where people believe things with religious intensity but it really isnt as complicated as it sounds. Avoid ground loops and put as much metal into the counterpoise as can reasonably be done and there you are! I wouldnt have hesitated to use the "nearest bronze thru hull" if only there had been one. It seems to me that the dynaplate is doing pretty much exactly the same thing the thru hull would do.

 

sck-
The Dynaplate is not just a solid bronze plate. It is sintered bronze, literally porous metal sponge, so if the surface area of a Dynaplate appears to be, say two square feet? It may actually have 200 (500?) square feet of contact area with the seawater.
Assuming that metal-to-water contact is the purpose and that it is a good thing (and not arguing for or against that) a Dynaplate is way more contact area than any thru-hull on the boat. The only precaution is that they must not be used as a lightning ground, because all that seawater in the porous plate can flash into steam and explode if lightning tries passing through.

 

hello

yes, dynaplates are supposed to have way more surface. I am not sure it really does after a few weeks of crap growing on it. But in any case the question was do they work? My answer is, yes they do. I have no doubt there are other ways, and if I had a bronze thru hull I would certainly have tried that, but if the OP wants to know if Dynaplates work my answer is yes, at least mine does.