SSB Backstay Antenna

[Zanshin]

I am looking into replacing my standing rigging with Dynex Dux (Dyneema with little creep). This is a single braid rope which started me thinking about using the hollow inner core for an insulated wire antenna since the Dynex is nonconductive. The manufacturer is looking into potential problems, particularly possible stress risers where the antenna cable leaves the core.

My question is what diameter is the minimum acceptable one and are ther pitfalls and problems in this approach which I haven't thought of?

[Laidback]

Need more info regarding the boat, the radio, the tuner, the band spread frequencies etc...

It may solve the problem by using a vertical whip antenna rather than trying to incorporate one inside a backstay.

[Hud3]

Zanshin,

There's been a bit of discussion on the topic in this thread...

http://www.cruisersforum.com/forums/...s-21574-2.html

[donradcliffe]

I have seen raceboats with a wire taped to the backstay--might need retaping once a year.

You probably want a minimum of #12 wire, to allow for accidental loads and some corrosion at the terminal end.

[Zanshin]

Hud - nice thread and informative. I am working with Colligo but they are asking which diameter SSB antenna cable they need to test with. The last mail from them indicated that the antenna cable could exit out of a part of the splice and not affect breaking strength. Lightning is certainly an issue, as Dyneema has a low melting point of around 150C compared to steel.

[s/v Jedi]

For concerns on the effect of the antenna wire on the strength of the rope, my first thought is that this effect will be there but it must be much less than the splices on the stays themselves, because for those splices, the whole rope diameter enters through the braid into the hollow core so the thinner wire has less effect. The rope splice should be tapered, often ending with just one strand, so I would keep my wire at or under the diameter of a single strand of the rope.

About lightning: yes, this would be the reason that I would choose for another way. We have no back stays at all and I use both a long whip antenna and a wire that I hoist. I don't really notice any difference between the two systems. We can't have a wire hoisted while sailing (same reason as we can't have back stays... the sails can't pass when tacking/gybing) but if I could, I might prefer that over a whip antenna. Have a good look at how some Amel's do this (I like that setup).

ciao!
Nick.