Mast Wire Management, HF Antenna, Internal Radar Reflector

Mast Wire Management, HF Antenna, Internal Radar Reflector

Postby betelgeuserdude » Thu May 24, 2018 2:43 pm

I’m nearly ready to prime and paint my carbon fiber Freedom 40’ masts, having removed the black gelcoat and applied Dynel/epoxy. I’ll be renewing the electrical wiring and coax in each mast, and I loathe wire slap. Searching the archives, I came across the oft cited solution of wire tie sea urchins, and then found Eric Sponberg’s description of a wire management system consisting of a 1x19 wire hung from the mast head, to which all other wires are secured. I like it.

Many years ago, I was employed as a rigger. I had ample opportunity to learn to hate the wire tie sea urchins, while also coming across sweet deals on spool “ends”. Needing a permanent HF antenna aboard my (different) boat, I stuffed a piece of 1x19 wire into a piece of Technora, which I then used as a secondary backstay. It worked incredibly well as an HF antenna while cruising full time for a couple of years.

I wonder if I could expect similar joy were I to employ a piece of similarly insulated wire INSIDE a carbon fiber mast. This would double as a wire management system too, which appeals to my sense of elegance. I know it’s doubtful, but has anyone ever used an HF longwire antenna INSIDE a carbon fiber mast? What if any problems were revealed?

I think it will be a simple solution to build a bridle or structure in the butt of the mast to maintain the orientation of the wire bundle in the center. This will allow tensioning as well.

Finally, it occurred to me that while my masts are horizontal, I could also install a couple of radar reflectors internally in each mast, through which the wire management system would run. These would be fabricated from perhaps 3mm aluminium plate, mimicking the conventional “catch water” style reflectors, and sized to fit approximately halfway up each mast.

One last thing... has anyone, with any joy, ever flown a spinnaker from the forward mast of a Freedom cat/ketch? I have no doubt that reaching sails have been employed from the after mast.
Sincerely,
David (Dave) Smith
~Eyrie of Astoria~ Freedom 40' AC CK (#63)
betelgeuserdude
 
Posts: 5
Joined: Sun Mar 19, 2017 7:53 am
Location: Lower Columbia River, Cascadia, Pacific Northwest, Left of the USA

Re: Mast Wire Management, HF Antenna, Internal Radar Reflect

Postby betelgeuserdude » Thu May 24, 2018 7:44 pm

Alas, my dream is not to be. The consensus among my fellow ham operators is that (at least the best described) the carbon fiber masts will act somewhat like a faraday cage with respect to RF transmitted by the antenna installed within. This also seems to suggest that the performance of a radar reflector installed within a carbon fiber mast will be suspect, if not an outright failure. Thus, I’m back to the drawing board.
Sincerely,
David (Dave) Smith
~Eyrie of Astoria~ Freedom 40' AC CK (#63)
betelgeuserdude
 
Posts: 5
Joined: Sun Mar 19, 2017 7:53 am
Location: Lower Columbia River, Cascadia, Pacific Northwest, Left of the USA


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