Ferrite Beads on HF Radio Installation

[Brian.D]

One more option... make a home made KISS counterpoise. Can't be any worst than what you have right now. Info can be found here.

As for the "Dynaplate", if you are going that far, then just get a piece of copper plate 8"x4"x.25". It will do the same thing. Stand it off the hull by .25" and you will get surface flow on all sides. Make sure the bolts go through the plate so that the plate can be removed when the hull is painted. Then replace the plate. That is, if you desire to use an external RF sea ground.

JMHO

[Jammer]

Originally Posted by Brian.D

One more option... make a home made KISS counterpoise. Can't be any worst than what you have right now.

I agree with Brian's comments as written. KISS counterpoises will put lots of RF inside the boat, and will not perform as well as a proper ground.

As for the "Dynaplate", if you are going that far, then just get a piece of copper plate 8"x4"x.25". It will do the same thing. Stand it off the hull by .25" and you will get surface flow on all sides. Make sure the bolts go through the plate so that the plate can be removed when the hull is painted. Then replace the plate. That is, if you desire to use an external RF sea ground.

Brian is again correct that the benefits of sintered copper over flat plate are theoretical and can only be realized in practice if the plate is kept clean and free of marine growth. I believe that 4"x8" might be on the small side especially if you're ever in brackish water.

[Dockhead]

Originally Posted by Jammer

I agree with Brian's comments as written. KISS counterpoises will put lots of RF inside the boat, and will not perform as well as a proper ground.

Brian is again correct that the benefits of sintered copper over flat plate are theoretical and can only be realized in practice if the plate is kept clean and free of marine growth. I believe that 4"x8" might be on the small side especially if you're ever in brackish water.

Thanks. I'm not doing a KISS counterpoise, which I believe to be snake oil (bundled wires will be inductively coupled). Nor am I doing a copper plate, because I do not desire to drill holes in my fully cored hull, nor will I be out of the water long enough to do it, nor do I want the drag.


So I think the three choices are : (1) rudder post (recommended by Bill Trayfors); (2) lifelines; (3) through-hull. The nearest through-hull is 5 meters or so away so I don't think that's a good solution. I think I'm leaning towards the lifelines.

[JPA Cate]

Originally Posted by Dockhead

Thanks. I considered using the regular backstay -- would be really easy to connect as the backstay chainplate is right next to the tuner. But then the whole rig would radiate, since I have no insulator at the top.


The parallel backstay solves all those problems, but it's extra windage and it's in the way, which is not good.

Fwiw, we've been using the whole rig for over 35 years, now. Works fine. One memorable time, we were playiing ham radio, from the Tuamotus to England, and the English chap was explaining to us how our antenna setup could never work....but we were still communicating just fine!

Ann

[Wotname]

You have received excellent advice from the RF gurus who have already posted in this thread.

As an aside, they must be right as I concur with them ()

Regarding the wire debate, I think historically the main concern was with using braided flexible copper flat strap that used to be seen in cars sixty years ago for battery ground cable. A flat solid copper strap was much better than that braided stuff. Somehow the argument morphed into strap versus normal round stranded cable.

IMO, 20 or 25 mm diameter copper tubing makes for a reasonable HF conductor; aluminium tubing (40 mm diameter) is used in several aircraft for HF feeds.

However you have already identified you main problem and the best solution, you are just hesitant about implementing it. It sounds like you want to be convinced that easier second rate measures will be OK. Now you are a guy who doesn't normally do 'near enough is good enough', you normally go for 'best practice'. Unless the HF is only being refitted as a plaything, I suggest you stick with best practice and fit the sintered plates.

Originally Posted by Dockhead

..............
But the ground is really a bitch. The nearest through-hull is really distant -- maybe 5 meters or even more. And a strap is impossible to run to it. I understand that the ground cable will resonant and go way up in impedence if it is longer than 1/2 wavelength -- I can't get it shorter than half the 30mhz wavelength (10m).



I could do one of those sintered plates, but I really don't want to drill a hole in my fully cored hull.


So what to do? .......

If your only concern is drilling hole in a fully cored hull, just take the time and effort and do it correctly. You know it can be done and you know if done properly, it isn't detrimental to the hull integrity.

In summary - do it right and to it once; your HF will love you for it.

[Jammer]

Originally Posted by Dockhead

Thanks. I'm not doing a KISS counterpoise, which I believe to be snake oil (bundled wires will be inductively coupled). Nor am I doing a copper plate, because I do not desire to drill holes in my fully cored hull, nor will I be out of the water long enough to do it, nor do I want the drag.

So I think the three choices are : (1) rudder post (recommended by Bill Trayfors); (2) lifelines; (3) through-hull. The nearest through-hull is 5 meters or so away so I don't think that's a good solution. I think I'm leaning towards the lifelines.

Well, you could try all of them bonded together ::shrug::


I believe your concern about the 5 meter distance to the through-hull is overblown given your willingness to consider alternatives that are less electrically desirable. Of the three choices, the through hull is easily the best alternative electrically, even given the distance, and regardless of what sort of conductive material you use (stranded copper wire in, say, 12 awg, would work just fine). The rudder post is, as I understand it, not in contact with the water in your boat, and the lifelines, well, there's a safety hazard there, and you'll end up with rf throughout your boat.

I would start with the through hull and if you don't like the result you can try something else or add a plate.


(If drag is your concern then make the plate as flush as possible and fair the edges. Bond it in place if you don't want fasteners. Drill a 3/4" hole for the wire, fill with epoxy with silica filler, overnight cure, drill a hole in the center for a 12 awg wire, seal to taste, done. The hole can be above the waterline if that is best for your situation, in your judgment. Not difficult nor particularly time consuming.)

[Brian.D]

RF is in the boat, regardless of what you do. There will always be a energy field. What you want is that RF to be going some where other than in to other electronics. How you do that is subject to many opinions. Both Gordon West and Bill Trayfors cover it nicely in their papers. Bill was a proponent of the KISS system while Gordon preferred sea water. Then there is John MacDougall's approach to building your own KISS.

Like I mentioned before, it will not cost you anything to try your own DIY KISS. I built one and tested it on a 35' longwire antenna at home, with the DIY KISS counterpoise. It tuned just fine and I was able to work many stations both voice and data. Just four wires of 33', 17', 16', and 14'.

Remember, what you are trying to do is emulate the other side of the antenna so you have something of a balance, if I may use that word. As long as the tuner has something to work against and your RF sinewave is not trying to get back to the radio.

Good luck, and let us know what your solution was and how it worked. This will be a good technical read for the next person that might have the same issues you are having now.

[stormalong]

None of these posts talk about your keel. Is your keel internal or external? Can you get to your keel bolts? Even an internal keel - a large surface area will capacitively couple to the water as a counterpoise. As long as you can make a good electrical connection to your keel you have a good ground (counterpoise).

On the topic of flat copper in your grounding system. RF energy travels on the surface of a conductor - the skin effect. The more surface area the better. Some marketers tout that thin copper foil is better. It is not. It is the surface area that counts. Very thin just means it will corrode faster and then they can sell you more.

The first red flag I see has already been addressed by others. Your active antenna starts at the antenna terminal on your antenna tuner. If your antenna tuner is in your nav station you are radiating RF directly to the nav station. First priority is to move it as close to your backstay feed point as practical. The feedline from the radio to the antenna tuner should be better than RG58, RG213 would be a better choice. I agree that LMR400 is not a good choice because it's conductors are aluminum. Connectors must be crimped - you cannot solder to the shield. The center conductor is copper plated aluminum so it can be soldered but the shield connection is just as important. Another common mistake is to use coax from the antenna terminal on the antenna tuner to the antenna feed point. That creates an RF choke of unknown characteristics - not a good thing.

Another issue to consider is your backstay antenna. I am not sure what you are saying about is being parallel to your other back stay. Do you have a split back stay or are you running a wire next to your back stay as an antenna? An antenna parallel to your real back stay will be radiating RF to your standing rigging that you want to be radiating into the atmosphere. All that RF in your standing rigging will in turn be radiated into your boat. Is your standing rigging grounded? Does the grounding share a connection to your DC ground? If so you are just dumping RF energy into your electronics via your DC negative. I know that there are people selling a line with a wire in it to use as an antenna - that is as much snake oil as the KISS counterpoise. If you have to run a wire up to the masthead place it so that is is the farthest away from other standing rigging as you can get and don't run it to the masthead. keep it at least six feet from the masthead.

The best solution is to put insulators in your backstay. I know many sailors are reluctant to do that a view that as a weak link in the rigging. They are also not cheap. A less desirable alternative is a 20 foot whip antenna angled away from your backstay. It is a poor performer, especially on lower frequencies as is any short antenna for HF.

[Dockhead]

Originally Posted by Jammer

Well, you could try all of them bonded together ::shrug::

I believe your concern about the 5 meter distance to the through-hull is overblown given your willingness to consider alternatives that are less electrically desirable. Of the three choices, the through hull is easily the best alternative electrically, even given the distance, and regardless of what sort of conductive material you use (stranded copper wire in, say, 12 awg, would work just fine). The rudder post is, as I understand it, not in contact with the water in your boat, and the lifelines, well, there's a safety hazard there, and you'll end up with rf throughout your boat.

I would start with the through hull and if you don't like the result you can try something else or add a plate.

(If drag is your concern then make the plate as flush as possible and fair the edges. Bond it in place if you don't want fasteners. Drill a 3/4" hole for the wire, fill with epoxy with silica filler, overnight cure, drill a hole in the center for a 12 awg wire, seal to taste, done. The hole can be above the waterline if that is best for your situation, in your judgment. Not difficult nor particularly time consuming.)

That's rather eye-opening. 5 meters of 12AWG wire to connect the ground to through-hull? I might even be able to get a battery cable through there. But I read a lot of bad things about long ground connections -- overblown?


A plate ABOVE the waterline? I thought it needed physical contact with the water?


I thought lifelines were known to work well?

[Dockhead]

Originally Posted by Brian.D

RF is in the boat, regardless of what you do. There will always be a energy field. What you want is that RF to be going some where other than in to other electronics. How you do that is subject to many opinions. Both Gordon West and Bill Trayfors cover it nicely in their papers. Bill was a proponent of the KISS system while Gordon preferred sea water. Then there is John MacDougall's approach to building your own KISS.

Like I mentioned before, it will not cost you anything to try your own DIY KISS. I built one and tested it on a 35' longwire antenna at home, with the DIY KISS counterpoise. It tuned just fine and I was able to work many stations both voice and data. Just four wires of 33', 17', 16', and 14'.

Remember, what you are trying to do is emulate the other side of the antenna so you have something of a balance, if I may use that word. As long as the tuner has something to work against and your RF sinewave is not trying to get back to the radio.

Good luck, and let us know what your solution was and how it worked. This will be a good technical read for the next person that might have the same issues you are having now.

Thanks. I get your point. Even if I were more open-minded to the KISS than I am, it's not practical on my boat, which has massive ring frames and stringers and very few ways to pass wire through the boat, and which few ways are already full of cabling. No way would I have such an antenna counterpoise bundled up with my N2K backbone.

[Dockhead]

Originally Posted by stormalong

None of these posts talk about your keel. Is your keel internal or external? Can you get to your keel bolts? Even an internal keel - a large surface area will capacitively couple to the water as a counterpoise. As long as you can make a good electrical connection to your keel you have a good ground (counterpoise).

I have 8 tons of external lead bulb keel, and I can get to my keel bolts. However, I have moved the tuner to the lazarette, so the keel is now 7 or 8 meters away, with no way to get copper strap there, and wire would have to run bundled up with sensitive cabling like my N2K backbone. I think this is not practical.

Originally Posted by stormalong

On the topic of flat copper in your grounding system. RF energy travels on the surface of a conductor - the skin effect. The more surface area the better. Some marketers tout that thin copper foil is better. It is not. It is the surface area that counts. Very thin just means it will corrode faster and then they can sell you more.

That corresponds to what I have been told. What about a 5 meter long connection to a through-hull? Can that be reasonably made with wire? No way to get strap through the already packed holes in my ring frames.

Originally Posted by stormalong

The first red flag I see has already been addressed by others. Your active antenna starts at the antenna terminal on your antenna tuner. If your antenna tuner is in your nav station you are radiating RF directly to the nav station. First priority is to move it as close to your backstay feed point as practical. The feedline from the radio to the antenna tuner should be better than RG58, RG213 would be a better choice. I agree that LMR400 is not a good choice because it's conductors are aluminum. Connectors must be crimped - you cannot solder to the shield. The center conductor is copper plated aluminum so it can be soldered but the shield connection is just as important. Another common mistake is to use coax from the antenna terminal on the antenna tuner to the antenna feed point. That creates an RF choke of unknown characteristics - not a good thing.

I have already moved the tuner to the lazarette.

I have proper GTO cabling to connect the tuner to the antenna.

What's wrong with crimping on a UHF connector onto LMR400? I have a set of quality crimpers, and crimp most of my coax connectors; have always had good luck with it.

Originally Posted by stormalong

Another issue to consider is your backstay antenna. I am not sure what you are saying about is being parallel to your other back stay. Do you have a split back stay or are you running a wire next to your back stay as an antenna? An antenna parallel to your real back stay will be radiating RF to your standing rigging that you want to be radiating into the atmosphere. All that RF in your standing rigging will in turn be radiated into your boat. Is your standing rigging grounded? Does the grounding share a connection to your DC ground? If so you are just dumping RF energy into your electronics via your DC negative. I know that there are people selling a line with a wire in it to use as an antenna - that is as much snake oil as the KISS counterpoise. If you have to run a wire up to the masthead place it so that is is the farthest away from other standing rigging as you can get and don't run it to the masthead. keep it at least six feet from the masthead.

Thanks, yes, I think I'm ok there. I'm aware of the coupling issues which is why I'm leery of the KISS ground. "Parallel backstay" is how Bill Trayfors and others refer to the system -- meaning not your own backstay, but a different wire, usually lifeline wire rope. Mine is indeed a piece of lifeline wire rope, with eyes on both ends, hung from a spare main halyard and running to a textile rope fixed at the stb quarter. My real backstay is about 24 meters long, and the antenna is only about 14 meters long, so the conducting part is well away from any of the rigging.

Originally Posted by stormalong

The best solution is to put insulators in your backstay. I know many sailors are reluctant to do that a view that as a weak link in the rigging. They are also not cheap. A less desirable alternative is a 20 foot whip antenna angled away from your backstay. It is a poor performer, especially on lower frequencies as is any short antenna for HF.

I would for sure have done this, except my backstay is 14mm thick, so insulators are rare and vastly expensive. I also admit that I don't like the idea of a weak link. If I keep this boat much longer, I might some day insert one 2/3 of the way up, just one, and then connect the tuner to the chainplate. Put some cover on the lower 2 meters of the backstay for safety. Meanwhile I think the parallel backstay is supposed to be quite a good solution -- I don't see how it is electrically worse than an insulated backstay. Windage is the main disadvantage.

[robert sailor]

Keep this in mind, it's been my experience that the lower frequencies seem to show just how well the system has been set up.....in other words I found that if I had excellent transmission with my lower frequencies I always got great transmission on my higher frequencies. I found that higher frequencies were never a good test for how well my ssb was working. Just my personal experience.

[Jammer]

Originally Posted by Dockhead

A plate ABOVE the waterline? I thought it needed physical contact with the water?

The plate has to go below the waterline.


The hull penetration where the ground conductor exits the hull, does not have to be below the waterline. You could, for example, have the ground exit the hull at the transom a few inches below the bottom of the chainplate for the backstay you're using as an antenna, and then connect to a plate using strap or wire or whatever.

I thought lifelines were known to work well?

Some people say they work well. I am skeptical. Well compared to what? Were measurements made? Are the results repeatable on different boats? Are the results reliable and consistent or do they vary from day to day? Lifelines are thin wire, stainless steel that doesn't conduct especially well, so there are going to be significant resistive losses. At the stanchions they may be sort of electrically connected, or not. Lifeline length varies from one boat to the next and there will be resonance points where the antenna is not usable. On some boats these may show up at problematic frequencies.



From a relative performance standpoint, your lifelines are the same diameter as wire between 8 gauge and 4 gauge. Figure 0.01 ohms per foot. 20 gauge copper would perform better.

[stormalong]

Originally Posted by Dockhead

That corresponds to what I have been told. What about a 5 meter long connection to a through-hull? Can that be reasonably made with wire? No way to get strap through the already packed holes in my ring frames.

Wide strap would be best. Large diameter thin wall copper pipe would be my next choice if that is possible. Wire has a small surface area unless it is very very large wire. Is it possible to cut a narrow slot through the bulkhead?

Originally Posted by Dockhead

What's wrong with crimping on a UHF connector onto LMR400? I have a set of quality crimpers, and crimp most of my coax connectors; have always had good luck with it.

Nothing wrong with properly crimped connectors on LMR400 since you have the crimping tool. Another caveat with LMR is that it is a foam dielectric and tight radius bends cause the center conductor to migrate towards the shield. Follow the cable specs and you are good.

I use both LMR400 and LMR superflex in my home ham shack. On the boat I use tinned RG213 going up the mast for VHF and for HF from the radio to the antenna tuner.

I would also suggest that the coax be routed separately from all other electric cables. Being in the same bundle is a good way to transfer RF into your electrical system. And keep it away from you autopilot compass sensor and it's wire too!

I think in your situation for an optimum installation some holes will need to be drilled through those bulkheads.

73,

Brian
N7BMW

[Dockhead]

Originally Posted by Jammer

. . . I believe your concern about the 5 meter distance to the through-hull is overblown given your willingness to consider alternatives that are less electrically desirable. Of the three choices, the through hull is easily the best alternative electrically, even given the distance, and regardless of what sort of conductive material you use (stranded copper wire in, say, 12 awg, would work just fine). . .

OK, so this is what I'm going to try first.



I have acquired 5 meters of 16mm2 tinned marine cable, which is AWG 6, 4x the area of AWG 12, the biggest cable I can get through the conduit I have.


I will clamp it to the ginormous 3" through hull which is my main engine water separator drain.



This cable has to go in the same conduit as control cables for Eberspacher heater, control cables for pilot solenoid, and rudder position sensor, also cables with power for the bathing platform hydraulics and some other stuff.



I guess I'm going to need ferrite beads on all of those? I sure hope I don't get a lot of RF in my engine room -- there are a lot of electronics in there.