• Mobile App For Android Now Online!

    Download it here. The app is searchable in the Google Play Store under Sailboat Owners.

    Sorry iPhone/iPad users, we are still waiting on Apple. :(

    Click the X in the upper right corner to make this go away

Seawater Grounding for High-Frequency Radios

Feb 17, 2006
5,078
Lancer 27PS MCB Camp Pendleton KF6BL
I may have posted this, or possibly someone else did, but in case it was not...

This is a good article by Gordon West on using Sea Water as your RF Ground vice running 100 SQFT of copper. Mr. West makes some very compelling arguments against using copper. This is an argument that may never end regarding Copper RF Ground vs Sea Water Ground.

(Download it and put it with your other documents)

Enjoy!

http://sfbaysss.org/resource/doc/SeawaterGroundingFor_HF_Radios_byGordonWest.pdf
 
Jan 25, 2011
2,219
S2 11.0A Anacortes, WA
I did something similar back in the mid 80s. Several hams in Seattle were trying to work a ZL (New Zealand) and were having issues. They were using 1KW amps into six element yagis 50 ' up. Along comes me with 100W, manual tuner, backstay ant., and grounded to a thru hull with a piece of wire (only thing I had at the time) floating in Lk Washington (Seattle). I broke in and asked if I could try to work the ZL and immediately got a 10 over report. Then I had to fess up what my setup was.
 
Sep 25, 2008
6,265
Alden 50 Sarasota, Florida
I did something similar back in the mid 80s. Several hams in Seattle were trying to work a ZL (New Zealand) and were having issues. They were using 1KW amps into six element yagis 50 ' up. Along comes me with 100W, manual tuner, backstay ant., and grounded to a thru hull with a piece of wire (only thing I had at the time) floating in Lk Washington (Seattle). I broke in and asked if I could try to work the ZL and immediately got a 10 over report. Then I had to fess up what my setup was.
This doesn't make sense - working ZL from the west coast running a kw to big yagis is a given.

As to what form of counterpoise (not grounding) is best, it's hard to screw it up given the antenna is surrounded by salt water.
 
Feb 17, 2006
5,078
Lancer 27PS MCB Camp Pendleton KF6BL
Well, there is another argument about "grounding" vs "counterpoise" vs "ground plane". Each is its own and has merits. Some hams think that grounding the radio/tuner to the AC ground lug is the same as using that ground as a counterpoise. Some hams think that the counterpoise that is "in the ground" is also an RF Ground. Then some hams think that the Ground Plane is also a "RF Ground" in sorts. Basically, each is somewhat correct.

But in this case, Mr. West is stating (I believe) that the Sea Water is both a counterpoise and a ground. Counterpoise to allow the virtual other half of the antenna to exist, and a source of allow stray currents to dissipate.

I have seen the argument that Sea Water alone is not a good counterpoise, but Mark shows otherwise by being able to work ZL on 100w while the Kilowatt guys were having trouble.

So I think either way, having your rig tied to the Sea Water is not going to hurt your signal, or operations. But... if you do decide to use a metal through hall, make sure you put in DC Block capacitors. Wouldn't want that thru-hull to break down due to electrolysis.
 

Rick D

.
Jun 14, 2008
7,002
Hunter Legend 40.5 Shoreline Marina Long Beach CA
Not smart enough to voice an opinion. For my SSB I took out the foil which had deteriorated. Put in a KISS counterpoise. We'll see how she works when I put in a ham station.
 
Mar 12, 2008
557
Jeanneau 49 DS San Pedro, CA
I've used both a seawater ground (copper foil to a thru hull) and a KISS. The problem with copper foil is is deteriorates and loses connection. I've found the KISS works better and seems to be very reliable. I installed it in 2010 and so far, no problems.
 
Jan 25, 2011
2,219
S2 11.0A Anacortes, WA
My little experience is not a direct comparison to Mr. Wests testing. I was floating in Lk. wash. And the yagi guys were somewhere else around Seattle. I think I just happened to have a propogation path and they didn't. (Could be)...I was vertically polarized and they were not. Not sure (more like can't remember) what the ZL was using...You can put a million tera Watts into an antenna and if you don' t have propogation to the other end, it aint gonna work. Forgot to mention we were working 15m. I remember also around that period, I would drive nonstop between Seattle and Phoenix and had an HF in the car. Several hams kept me company during the night hrs on 75m. Conversations didn't last long cuz I was moving and lost propogation. People were stepping right on top of our QSO and I was getting a little testy..Then I realized I was moving and going in/out of different prop paths....When I fix my Icom 745, I'm going to look into the KISS....I decided to stay with the analog radio instead of digital. In talking with the technician, trying to determine if its worth it to fix, he said a lot of people are still liking the analog radios cuz of digital noise. And, when I was messing with a digital one, I did not like the stairstepping of freq changes when the tuning knob was rotated. But I digress...Its the wine..
 
Feb 17, 2006
5,078
Lancer 27PS MCB Camp Pendleton KF6BL
Mark, if you are interested in the KISS, and it does get good reviews, read this thread. The KISS design concept in outlined on page 6 of the thread. But read the whole thing. It is very interesting.
 
Jun 6, 2006
6,991
currently boatless wishing Harrington Harbor North, MD
I had a similar experience on the bay. Just got the radio and was itching to try it on the boat so just used a piece of coax from the transceiver. attached the center wire to the backstay with an alligator clamp and the ground to a piece of heavy wire which I put a nut on the end of and threw over the transom. the yaesu 819 puts out a smokin 5 watts at full power so I was not expecting much. reception was great on 20M with lots of Europe and Alaska coming in loud and clear. called CQ and got a guy in Italy right off the bat.
And that was in brackish salt water not the full strength stuff in the ocean!! Given that the backstay is split and grounded at the mast head to a metal mast I figure I energized the entire mast and rigging and still had 1.2 SWR. Just because I had read lots of "grounding on boats" stuff I tried pulling my ground wire out of the water. reception went south and SWR went off scale. This setup worked on 80, 40, 20M great, 10M reception was good but SWR was up toward max.
I'm a firm believer in just connecting to the water and not having lots of stuff in the boat. I think the key is to not have the feed point of the antenna very far from the surface of the water. I've seen this on boats a lot. Not thinking I'd put my ground radials on the ground and then hoist my feed point 15 ft in the air on a land based antenna but that is basically what you are doing when you use an insulated backstay with a matching unit that has the ground located on a thru hull.
 
Feb 17, 2006
5,078
Lancer 27PS MCB Camp Pendleton KF6BL
Bill, we all know that the feed point of a backstay antenna is not at the backstay, but rather the antenna tuner output post. Given that the length of the cable between the tuner and the backstay is an active part of the entire antenna system. So what if the tuner is installed below the waterline? Does that constitute a feed point "under (virtual) water"? Is it important to have the tuner placed above the waterline?

So how much of the wire overboard was bare? In essence, the entire piece of wire can be bare for all that matters. Mr. West does not recommend wire but copper strip. However, it appears your experiment has proven otherwise. Would have been interesting to see the difference between wire and copper strip in the water.

Gonna have to ponder on that one.
 
May 10, 2004
112
Hunter 340 Bremerton, WA up from Woodland
I have good success with 1/2" or 1" tinned braid bolted to an old bronze strainer, then thrown over the side during ops. The tinning retards the copper corrosion rate. The most important thing, IMHO, is to drop to the sea as close to vertical under the feedpoint as possible. Also, pick the antenna length as close to odd 1/4 wavelengths (for the band(s) of interest) as possible to work the current maxima against that magnificent seawater plane.
 
Feb 17, 2006
5,078
Lancer 27PS MCB Camp Pendleton KF6BL
So Steve, you get good results doing that? Well, it is expedient for sure. So we have a nut, a strainer, maybe small old anchor would work. LOL
 
May 10, 2004
112
Hunter 340 Bremerton, WA up from Woodland
Works well, Brian. However, I am never sure whether the strainer is doing any good and the braid itself is making most of the contact, or vice versa. The only downside is that I can't have this thing banging against the hull for underway ops, so I have another braid from a nearby thru-hull that I can clip on in that case. But, if an anchor is what you got, go for it :biggrin:
 
  • Like
Likes: Brian D
Feb 17, 2006
5,078
Lancer 27PS MCB Camp Pendleton KF6BL
Steve, I was thinking about what you were using and started engineering a bit. Dangerous, very dangerous. Yeah, the first thing that came to mind was the banging of the strainer while underway. So, why not a copper ground rod. Not the long one, or maybe the long one cut in half. Attach it to the transom just about the waterline and it is always there.

Like I said, dangerous, very dangerous. LOL
 
Jun 6, 2006
6,991
currently boatless wishing Harrington Harbor North, MD
I've actually seen a metal "fin" mounted to the hull and used as the 'ground strap'. Said it worked well.
As for using the sea water for a ground you have to realize that you are only energizing the top inch or so to create the RF counterpoise. So as long as the ground strap touches the water you have a good connection. No need to run the it deep into the water. And while we are talking how deep in the water you connect to the counterpoise I'd not recommend using the keel as it would have to capacitively connect to the water surface to actually work..... same argument against thru-hulls and prop shafts and sintered grounding plates. You want to connect to the water AT THE SURFACE not underwater and have to work your way up.

Brian, your comment about the antenna actually starting at the tuner is (of course) correct. given that the tuner will correct for that extra length of radiating antenna it should not matter much but I'd think you would want to factor that into the actual length of the backstay radiator making the total length the 39' (think that is the "least unacceptable length" they quote). and yea a braided strap would, no doubt, work better.
 
Sep 25, 2008
6,265
Alden 50 Sarasota, Florida
Putting some copper in the water to serve as an RF counterpoise is equivalent to using one of those scintered ground plates attached to the hull which, conventional wisdom says isn't either effective or a proper use (of the plate).

What is the distinction which leads youguys to think it works more effectively than other methods?
 
Feb 17, 2006
5,078
Lancer 27PS MCB Camp Pendleton KF6BL
@Bill Roosa , Mr. West said the same thing. He put his strap at the 6" level in the water. So it would go to say that shallow is the operative word. However, under way would make for a difficult time if there is lots of rolling bringing the ground strap out of the water. This is why I proposed the rod. If long enough the rod should still make contact with the water when the boat is rolling.

Like I said, dangerous. Probably more of an overkill I guess. LOL

@Don S/V ILLusion, you talked about two different things in your sentence, but asked a question about difference. Not sure if you are asking why we think the copper strip works or why the plate works.

I am just going by what was written in the article by Gordon West. He has been deem SME in all things nautical communications. We know the plates are big and expensive. Maybe because of that we think they indeed work better. However, it could be more towards marketing to get the same profits that the 100 SQFT of copper sellers are making. I don't know.
 
Jun 6, 2006
6,991
currently boatless wishing Harrington Harbor North, MD
Well, the sintered ground is underwater and the wire/braid pierces the surface. Lets use a land based example to illustrate. Is it recommended to bury you ground plain wires (counterpoise) (don't you just hate the lexicon?) as deep as possible? No you just want them in good electrical contact with the ground (water). In fact burying them is counter productive (and hard work too). The actual RF that is going into the ground only penetrates to a very small distance. We are talking electric and magnetic fields propagating along the ground surface (sea surface). Sea water being much more electrically conductive than dirt is what makes sea water such a great counterpoise. So when you "bury" the counterpoise by using the keel, a thru-hull, or sintered ground you are electrically doing the same thing as deeply burying your ground plane wires.
think about trying to maintain an electrical field inside a good conductor. You cannot and the only electrical field is on the surface. Wires work the same way which is why you want to use a braid instead of a wire, more surface area to create the magnetic and electrical fields....... The sea water counterpoise is a surface phenomena and burying you connection to it is counter productive. I'm not even going to consider capacitively connecting to sea water using copper foil as a solution given the difficulty installing and maintaining it and how much easier it is to just connect directly to the worlds greatest counterpoise.
 
Jun 6, 2006
6,991
currently boatless wishing Harrington Harbor North, MD
Also understand that installers have kids to send through college. If the "solution" is dropping a wire braid in the water that is pretty hard to charge $$$$$ for. Pulling the soles and installing copper foil is much easier to brief as a high dollar job. Just saying.
 
Feb 17, 2006
5,078
Lancer 27PS MCB Camp Pendleton KF6BL
You are correct Bill.

There are people who own boats. There are people who own boats that want SSB installed. There are people who own boats that have SSB installed and are not ham radio operators. Those are the ones that will listen to the advice of installing either the copper foil or the copper plate. And then there are those of the above who will experiment with different approaches. That is a very small minority of sailors. So I think for now the copper installers and plate installers are safe. Besides, they do good work.

And then there are those who install a KISS. :)