Insulated back stay

[Celestialsailor]

It's getting time to do my standing rigging. I thought a novel idea would be to run an insulator near the top of the mast but not one near the bottom. I would connect my GTO-15 on the chainplate inside the rear locker to the antenna tuner. To prevent RF burns, run a 6ft. PVC pipe over the wire to the deck. Anyone have experience with this?

[SailingHarmonie]

I kind of like the idea of the insulator where I can look at it often, since it is the most fragile piece.

What do you see as the benefit?

[Celestialsailor]

Originally Posted by SailingHarmonie

I kind of like the idea of the insulator where I can look at it often, since it is the most fragile piece.

What do you see as the benefit?

You are basically adding two failure points with two insulators. What do you see as the benefit of two?

[s/v Jedi]

Originally Posted by Celestialsailor

It's getting time to do my standing rigging. I thought a novel idea would be to run an insulator near the top of the mast but not one near the bottom. I would connect my GTO-15 on the chainplate inside the rear locker to the antenna tuner. To prevent RF burns, run a 6ft. PVC pipe over the wire to the deck. Anyone have experience with this?

It’s the right way of doing it

[Celestialsailor]

Originally Posted by s/v Jedi

It’s the right way of doing it

To clarify, you mean use one insulator and use the chain plate as the termination point to attach the GTO-15 line?

[s57ra]

I have two norseman insulators on my Backstay, and i would recommend to avoid them.
I had an incident that the upper unscrewed and the Backstay landed on my stern and Bimini, where the insulator punched a bih gole in a brand new Bimini. Luckily the sails were not up and nobody was at the stern deck as it happened, it would easily kill somebody. It seems the rigging company that installed the insulators did not use thread locker or it did it wrong.
When I reinstalled it, I wsed the jb weld instedof thread-locker.

You can just run insulated wire from the top of the mast to the stern if you need HF antenna.
Cheers, s57ra

[s/v Jedi]

Originally Posted by Celestialsailor

To clarify, you mean use one insulator and use the chain plate as the termination point to attach the GTO-15 line?

Yes, exactly. You do want to check that the chainplate, as well as the backing plate have nice, clean fiberglass around them because a greasy residue isn’t a good RF insulator. Fiberglass is.

Also, while RF burn isn’t fun at all (I built many transmitters and have scarring on my fingers from RF burn) it also isn’t something to worry too much about. I wouldn’t use a PVC pipe but just a tight fitting new style split loom, like this:
https://www.amazon.com/gp/product/B07FW86XV6

[Celestialsailor]

Originally Posted by s/v Jedi

Also, while RF burn isn’t fun at all (I built many transmitters and have scarring on my fingers from RF burn)

Must come in handy not leaving fingerprints in your other line of work..
Actually, this will allow me to run a longer wire. Usable antenna lengths for my boat are 29',35.5' and 41'(41' being preferred), since my backstay is 48'6" long and I will need to install the insulator, up top, some distance down the stay in order not to have the mast interfere with the RF from the wire.

[The Yacht Rigger]

Originally Posted by s/v Jedi

Yes, exactly. You do want to check that the chainplate, as well as the backing plate have nice, clean fiberglass around them because a greasy residue isn’t a good RF insulator. Fiberglass is.

Also, while RF burn isn’t fun at all (I built many transmitters and have scarring on my fingers from RF burn) it also isn’t something to worry too much about. I wouldn’t use a PVC pipe but just a tight fitting new style split loom, like this:
https://www.amazon.com/gp/product/B07FW86XV6

Interesting thread. I've never seen this done this way.
I'm curious if the clevis pin connection, bronze turnbuckle assembly, etc don't create any resistance issues at all?

[Celestialsailor]

Originally Posted by The Yacht Rigger

Interesting thread. I've never seen this done this way.
I'm curious if the clevis pin connection, bronze turnbuckle assembly, etc don't create any resistance issues at all?

I suppose you could attach the GTO-15 wire right above the lower eye/swage instead of the chainplate which is about 18"s away. Good point.

[Jammer]

Originally Posted by The Yacht Rigger

Interesting thread. I've never seen this done this way.
I'm curious if the clevis pin connection, bronze turnbuckle assembly, etc don't create any resistance issues at all?

Well, I've rehabilitated myself from HF, but if I were trying to make a backstay antenna on my boat....


My boat has a split backstay. I would skip the lower backstay insulator(s) but would run some insulated, tinned, stranded copper wire from the antenna tuner, through a grommet in the hull, spiral wrap it up around one side of the backstay, up above the Y plate in the backstay, and attach it to the stainless steel backstay cable with a split bolt or something. Electrically it would look more or less the same and would eliminate possible intermittent problems over the years due to the hardware you mention. On the down side it would put the splice out of reach where it is harder to inspect.

[Celestialsailor]

From my understanding from many a boat ham,,,you should not use stranded copper but instead GTO-15.

[The Yacht Rigger]

Originally Posted by Jammer

Well, I've rehabilitated myself from HF, but if I were trying to make a backstay antenna on my boat....


My boat has a split backstay. I would skip the lower backstay insulator(s) but would run some insulated, tinned, stranded copper wire from the antenna tuner, through a grommet in the hull, spiral wrap it up around one side of the backstay, up above the Y plate in the backstay, and attach it to the stainless steel backstay cable with a split bolt or something. Electrically it would look more or less the same and would eliminate possible intermittent problems over the years due to the hardware you mention. On the down side it would put the splice out of reach where it is harder to inspect.

I'm FAR from an HF pro, so please excuse the ignorance. On all split backstay setups with insulators installed that I've ever seen, every one of them has always had three. One about 7' off the deck on one lower leg, another on the top of the other lower leg just below the swage, and then a third up near the masthead. So my assumption is that there is current passing back down through the delta plate and fittings - not sure how much though.

[s/v Jedi]

The only reason to use GTO wire is because it has a high voltage insulation, preventing RF burn when you touch it.

For RF performance, an 8 AWG wire would work better.

Obviously all metal and carbon boats must use a lower insulator; fiberglass is a good insulator so you can skip the lower insulator, but you still need a certain total length. This length starts at the terminal of the antenna tuner, so the GTO-15 wire going from the tuner up the rig to above a lower insulator… is actually part of the antenna. GTO-15 isn’t coax cable, there is no shield, just the single conductor.

[Jammer]

Originally Posted by The Yacht Rigger

I'm FAR from an HF pro, so please excuse the ignorance. On all split backstay setups with insulators installed that I've ever seen, every one of them has always had three. One about 7' off the deck on one lower leg, another on the top of the other lower leg just below the swage, and then a third up near the masthead. So my assumption is that there is current passing back down through the delta plate and fittings - not sure how much though.

Sure, that's the official way to do it. The only useful thing it accomplishes is to keep (some of the) high-voltage RF off the portions of the rig that are within easy reach of someone in the cockpit. It doesn't make for a more effective antenna.


But again, I've rehabilitated myself. My present cruising ground (Great Lakes) has comprehensive VHF coverage from U.S. and Canadian shore stations. When I venture beyond that, I'll get an Iridium Certus setup, because it's more effective overall, and cheaper when all costs are considered.


I have hobby HF gear and will experiment aboard with half-wave dipoles with it one of these days when I'm in the mood.