SSB Antenna Options

[S/V Illusion]

Originally Posted by Ryban

I don't think the system is currently grounded though, at least not from my inspections. Is there a reason why copper strapping is recommended as the ground connection instead of copper wire? Are there any concerns about providing a path for stray current corrosion (in a marina) by using a thru-hull as a ground in this way?

I've also been considering swapping all my old Groco seacocks for TruDesign composite ones, which might require me to re-think a grounding strategy long term.

Don’t confuse grounding (for electrical ground) with a counterpoise.

Lots of studies demonstrating a single point connection to a thruhull serves as an effective counterpoise for the antenna to work off. Copper strap is preferable because current flows on the conductor surface - more surface area, better conductivity.

For grounding, multiple path grounds can be avoided by simply interconnecting everything to a common point ground to preclude stray current problems. Any size wire will suffice unless you want to bring lightning considerations into the discussion.

[Brian.D]

Ryban, give this article a read, if you haven't already. Some excellent information.

[Celestialsailor]

On my Halberg Rassy 35, I ran a random wire up to an extension crane at the masthead. Used a length of dacron line as to keep it as far away as possible from the mast. Terminated that 7ft. high off the deck and ranGTO-15 to the tuner mounted on the transom, then coax to the HF set. My counterpoise at first was a thru-hull. Later I installed a 2"x12"x1/4" copper plate, thru-bolted with bronze machine screws and stood it off the hull about 3/8". This was my new counterpoise. One thing I noticed during the next haul-out was the bottom paint around the counterpoise was deteriorated a little bit. Maybe RF? I don't know. The set up worked well and I may do it again when the time comes to install a rig on my Pearson 365.

[MicHughV]

I can only add here that my homemade end fed long wire worked excellently. The insulators I used were small...maybe 3" in length and a coupla bucks each...can't remember where I got them from, but they were locally available from a hardware store as I recall.
I could bang out a signal half way around the world without any problems.
My girlfriend's dad at the time, was an old time ham, who insisted on being able to stay in touch with his daughter, which led me to get my license. His backyard was festooned with antenna's and we never had issues hooking up.

I do think a good ground is important though. My first boat had a steel hull, so plenty of ground there. Next boat had a tandem pair of big copper grounding plates.

[hasse_A]

This input might not help the TC but might give others an idea.
The boat has got a GRP hull/deck that isolates the chain plates.

My backstay installation is as fallows.

1) I have dual backstay.
2) Up at the top I have 2 insulators, one on each stay.
3) Just below the insulators the 2 stays have a short wire crimped on to them to have them shorted there.
4) At the bottom end I have no insulators.
5) Below deck the two chain plates are connected together.
6) The tuner sits close to one f the chain plates and is connected to it.
7) The turnbuckles and the stays are isolated 6-7 feet from the turnbuckles to keep my wife from getting curly hair.

This gives the me.
1) A of wire aloft.
2) A wide band antenna. I do not need to re tune when changing frequency as long as I am on the same band.
3) the security of having tow backstays if for any reason one of them breaks, for instance a failure in on one of the insulators.

/Hans

[Jon Hacking]

Originally Posted by Ryban

...I'd like to keep our SSB transmit capability, mostly for redundancy, and am wondering what options are available that don't require installing insulators on the backstay...

Our cat doesn't even have backstays per se, just cap-shrouds that are a couple meters aft of the mast.

I don't like to break my rigging with insulators, so I just ran a wire from the deck amidships up to an upper spreader. The top few feet are 3mm (1/8") nylon, to act as an insulator. The automatic tuner is in the head, behind the toilet, pretty much right under the antenna, with a grounding strap going down from the tuner to a Dyna-plate.

I wanted thicker wire for my antenna, so I used a length of coax, feeding just the outside (shield) so not using it as coax at all, just a thick wire. The feed from the radio to the tuner is, of course, coax.

This isn't ideal, but it's the best compromise I could come up with. The mast affects the signal, so it's somewhat directional, but it seems to work well.

[j.g.evans]

I made an extensive model of my sailboat, including: mast, rigging, lifelines, with a backstay antenna. I simulated having the backstay insulated at the top and not insulated, i.e. connected to the top of the mast. The antenna patterns were quite ugly at some frequencies with and without the insulator. The RF couples into everything and re-radiates.
Finding no clear method I decided to not cut the backstay install an isolator and see what happens. The automatic tuner worked every time and the SSB radio performed well. Optimum? No.
I connected the antenna tuner below deck where the bolts attached the backstay. All out of the weather.

[gega]

After reading this thread I have a feeling that either this product is not working:
Gam Electronics Split Lead SSB Backstay Antenna
GAM/McKim Split Lead Antenna | USA made VHF/UHF Antennas & Accessories
or something is not correct about the description of the electrical properties of the added extra wire
or - of course - I misunderstood something which would be the best case.


Anyone can help me to understand the requirements of the properly installed antenna?