Ground Plane Tape for HF Radio

[roverhi]

I'm running 3" wide copper tape under the deck near the rail on both sides for the HF radio ground plane. There is a lot of through deck fasteners along the way, some in the way of the tape run. Does it hurt the effectiveness of the tape as a ground plane if I fold the tape in 1/2 to get around a few of these fastenes/backing plates?? Probably not more than 5 or 6 areas for a length of 3" or so each to fit around fasteners and backing plates.

Assume I need to insulate any fasteners that may come in contact with the tape. These fasteners are for ungrounded deck hardware like lifeline stanchions and blocks, btw.

Where the copper tape is freehanging, intend to glue it in place with 5200.

The Icom AH-4 tuner is mounted on the stbd side on the lazarette bulkhead. Planned on making a right angle turn at the lazerette bulkhead to go from port side to the tuner on the stbd, a distance of maybe 4' Seem to remember that the tape is supposed to run as straight as possible. Can do away with the right angle turn at the bulkhead by running the tape diagonally under the cockpit with about a 30-40 degree bend in the tape at the galley bulkhead if it would be better. Won't be easy running or supporting the tape under the cockpit sole, however.

[btrayfors]

Don't worry about the thru-deck fasteners. Punch a hole in the foil. Whether they contact or not is immaterial to the function of the counterpoise.

That said, have you done the first and easy thing first: connected the foil from the tuner to the nearest bronze thru-hull, which is not otherwise bonded? Often, that's quite enough.

You can also use radial wires (insulated wire of any type). You needn't necessarily use foil, despite the garbage advice which is often found in user manuals and SSB books about not using wire. That is pure nonsense, demonstrably so.

To make wire radials most effective, use 1/4-wavelength at desired frequency bands (234/freq in mHz = wire length in feet). You can also use untuned radials. More shorter ones are better than fewer longer ones.

Bill

[s/v Jedi]

Well Bill, your argument that wire is as good as foil is nonsense, not the advise from manufacturers and books to use foil. So, if you care to stand by your statement, you better defend it with reasoning and technical explanation ;-)

The skin effect of RF power traveling through conductors is what makes surface area important.

I just finished redoing the foil aboard Jedi as at some places it was half gone after 6 years. I now made it part of the hull by epoxying it into the bilge and painting it. I can only advise you to do that now so you'll save yourself redoing it later.
I used that G/5 (5-minute) epoxy from West System and BilgeKote for painting it.

The attached photo shows the result of the part where it connects to the copper mesh that is part of the laminated hull (the foil only connects the tuner to that mesh). The green stuff is the oxidation of the old foil that was half gone here.

cheers,
Nick.

[richardhula]

The foil (& it needs to be foil) should be run along the bottom inside of the hull so that a capacitive connection to the sea can be made.

Whatever people say I have foil running directly from tuner to radio picking up on ground plate, through hulls & main anode along the way. It works great. Regularly used to get Sailmail connection to Lunenburg in Canada (3000+nm) from Tunisia.

[GordMay]

Would someone describe (or picture) the method of folding foil/tape at corners for a change in direction?

[btrayfors]

Jedi and Richard,

Sorry, guys, but you're both mistaken. Ever hear of wire radials? Elevated ground planes?

What do you think a dipole is? Mount it vertically on a sailboat, and you've got the most effective antenna you can put on a crusing sailboat (single-band only, though). All wire, no separate ground plane, no physical or "capacitive" connection to the water.

I do this for a living these days, and have decades of experience mounting antennas on sailboats. And testing them against other types of installations. The foil-only argument is pure, unmitigated C R A P.

Foil is fine to use for certain situations, e.g., just running a short length to the nearest thru-hull a la Gordon West. But the famous "100sq ft of copper" is pure bunk.

Wire radials work very well. So, too, do aluminum toerails, s/s rubrails, long metal deck-to-hull joiners, big radar arches, and any number of other solutions for an RF ground.

Bill
WA6CCA

[richardhula]

Originally Posted by btrayfors

Jedi and Richard,

Sorry, guys, but you're both mistaken. Ever hear of wire radials? Elevated ground planes?

Yes I have but my suggestions are based on fact i.e. it's the way most people do it, it works very well on a range of frequencies in conjunction with a back stay antenna, it's easy to do etc.

Remember there is more than one way to crack a walnut.

Mistaken is not the word you should be using. If your in the trade you should know better

[richardhula]

Originally Posted by GordMay

Would someone describe (or picture) the method of folding foil/tape at corners for a change in direction?

I have a feeling this is a catch question

[GordMay]

Not a trick (catch) question; just a “tricky” procedure to describe - let me try:

To make a square corner at a 90 horizontal bend in a ground foil:
Bend the foil over at 90 degrees, leaving a biassed corner edge.
Then, bend the bent section back over on itself, now leaving a square corner edge.

I’m not satisfied that describes it adequately, hence the earlier plea.

[btrayfors]

Originally Posted by richardhula

Yes I have but my suggestions are based on fact i.e. it's the way most people do it, it works very well on a range of frequencies in conjunction with a back stay antenna, it's easy to do etc.

Remember there is more than one way to crack a walnut.

Mistaken is not the word you should be using. If your in the trade you should know better

Richard...

Perhaps I wasn't making myself clear.

What is mistaken is the belief that RF grounds must be built only with foil, and that wires won't work. Also, that radials must be "capacitively coupled to seawater".

Both of these notions are Wrong. Mistaken. Erroneous. Ill Founded. Disproven. Incorrect.

Sadly, they are too often repeated by people who should know better, as well as other "believers" who shouldn't and don't.

I'm not anti-foil. I use it in installs where it makes sense. But, as you say, there are many ways to "crack a walnut", and foil is just one of them.

Bill

[Wotname]

Originally Posted by GordMay

Would someone describe (or picture) the method of folding foil/tape at corners for a change in direction?

Originally Posted by GordMay

Not a trick (catch) question; just a “tricky” procedure to describe - let me try:

To make a square corner at a 90 horizontal bend in a ground foil:
Bend the foil over at 90 degrees, leaving a biassed corner edge.
Then, bend the bent section back over on itself, now leaving a square corner edge.

I’m not satisfied that describes it adequately, hence the earlier plea.

Pardon my ignorance but does it matter?

I have always just bent it or folded as required to change direction. As we are only talking HF frequencies a piece of wet string will ALMOST suffice - OK it won't work that well but I have seen so many many poor HF installations that work some of the time, that I truly believe we worry too much at times about getting perfect.

Sure some people should worry more and do more to get it right but if one follows the general recommendations of manufacturers and professionals like say Bill, and then just do the best they can with what they have, the HF will work.

[GordMay]

Here’s some different takes on the subject:

Gordon West ➥ http://www.kp44.org/ftp/GroundingCou...stChapter8.pdf

Icom ➥ http://www.icomcanada.com/techbullet..._grounding.pdf

Dr. John Gregory ➥ Installation Procedure

[s/v Jedi]

Originally Posted by btrayfors

Sorry, guys, but you're both mistaken. Ever hear of wire radials? Elevated ground planes?

Wire radials are buried into the soil. If you bury foil it'll be gone before you close the trench it is in.

Elevated ground planes: same thing, copper foil won't work because it'll just hang down, break off etc.

The foil doesn't have the physical strength characteristics needed for those applications.

What do you think a dipole is? Mount it vertically on a sailboat, and you've got the most effective antenna you can put on a crusing sailboat (single-band only, though). All wire, no separate ground plane, no physical or "capacitive" connection to the water.

A dipole isn't a ground plane antenna so it's mode of operation is different. The section connected to the tuner-ground is called the "passive" side or whatever the correct English term is; it isn't the antenna ground. And again, foil doesn't have the physical characteristics required plus it would create a directional radiation pattern.

The foil-only argument is pure, unmitigated C R A P.

I agree with that. But the argument that foil works better (skin effect) is a correct one.

But the famous "100sq ft of copper" is pure bunk.

In real world situations on boats, I agree. But when you make a (capacitive or not) connection to the sea water, you actually take a big chunk off that 100 sq ft figure. Same if you connect metal parts like toerails etc. You replace copper with those metal items and/or sea water. I think the 100 sq ft guideline is a theoretical one and replacing copper surface with existing metal parts and coupling with seawater should be included in that same section of the manual or book.

So, use foil where you can to make RF ground connections because it works better than wire. Protect the foil against the environment or it won't last. I would rather fold the foil for a couple of inches to pass a fastener that's in the way instead of punching holes. When you fold, you increase the RF resistance but only for that short section. The big reason for folding is to protect the foil and have clear access to fasteners.

At shortwave frequencies, the implementation is all relatively easy and forgiving. The higher the frequency the bigger the penalty when something is off. For a shortwave install on a boat, it's the lowest frequency used that is the hardest to do right because of the big lengths required on a relatively small vessel.

ciao!
Nick.

[fairbank56]

It's interesting to note that Icom's instruction manual on grounding and antenna considerations states; "Now here’s another very important point, no round wires for RF ground!" and yet inside their tuner's the connection from the ground stud to the circuit board ground plane is a 4" piece of 16 gauge round wire.

The problem with all this is that it is difficult to prove what works best. Just being able to make a contact with a station hundreds or thousands of miles away is NOT an indication of your antenna systems efficiency. I have a very inefficent antenna system on my trailblazer (auto-tuner with 8' whip on back bumper) and make these contacts all the time. I made a contact with a New Zealand station early this morning on the 40 meter ham band from Maryland on a boat on the hard with nothing but 12' of GTO-15 coiled up on the deck for an antenna. The one area where you may see a difference with one ground plane system over another is with how your transmission affects your other onboard electrical/electronics system with interference.

Eric

[GordMay]

Originally Posted by fairbank56

It's interesting to note that Icom's instruction manual on grounding and antenna considerations states; "Now here’s another very important point, no round wires for RF ground!" and yet inside their tuner's the connection from the ground stud to the circuit board ground plane is a 4" piece of 16 gauge round wire...

Interesting incongruity.
Reminds me of the Xantrex manual that contained a wire length to size chart, requiring cables roughly twice the size of the permanent equipment lugs.