GTO-15 Length

[CAELESTIS]

I have a split backstay that is roughly 20 feet from the deck to the isolator after the "Y". The tuner is about 5 feet from the hole in the deck prior to its ascent up the backstay for a total length of 25 ft.

Is this an unacceptably long run of GTO-15? The tuner is in a dry secure spot on the aft bulkhead in the lazerette. I do not have many options to move it closer to the hole. If I did, the run would still be about 21 feet.

Additionally, I prefer not to use standoffs. I've been told to place the GTO-15 inside some 3/8 fuel line hose and wire tie to the backstay.

Thoughts? Comments?

[s/v Jedi]

There are many different views on this but I think all agree that the tuner should be as close to the deck gland as possible. I think 5' is too much and 1' is very good (say 2' maximum).

You should look at this cable as an antenna cable... you should look at it as part of the antenna (it is). If you do not use stand-offs you should use GTO. I prefer 8 AWG which has much less insulation value so must use stand-offs if I would tie it along a stay (I don't).

The fuel hose is a good idea but make a 180 degree turn at the top so that as little water goes in as possible. The hose provides UV protection, I don't think it provides (or you need) additional insulation value. You should try it and if it works you're done. If you have trouble you can always try stand-offs.

cheers,
Nick.

[Paul Elliott]

The hose isn't needed for insulation, but it will reduce the capacitive coupling between the GTO and the grounded backstay -- this is a good thing. It won't reduce the coupling as much as an equivalent air gap, but it is better than just tying the GTO directly to the backstay.

I have an adjustable backstay, and use two lengths of small-diameter PVC pipe, fitted together "trombone-style" to enclose the GTO feed wire, and stand that off about one inch from the backstay. There are two 90-degree fittings at the top to help keep the rain out. Letting the PVC sections slide makes for a cleaner installation than attaching the wire directly to the fixed standoffs. It looks a little like a plumbing-supply shop back there though.

[fairbank56]

As Nick says, this wire is part of your antenna. It radiates just like your insulated section of backstay. Just make sure the part inside the lazarette is away from other wiring and bonded fittings and you should be fine. You should see the way the idiots that wired the new fleet of sloops at the Naval Academy did it. They installed the tuner on the port forward bulkhead of the lazarette and put the thru-deck fitting on the starboard side. They had some 15 feet of gto15 running inside the wire loom with the radar and gps cable! These boats also have the split backstay like yours. After delivery of the first 7 boats, I finally got them to have the wire exit the port side but they are still running it in the wire loom. Iv'e had to re-do all of them (12 boats so far). The gto15 is run through 3/4"O.D. clear water hose which is tie-wrapped to the stay. They initially had no protection from water at the top so I just sealed them with rescue tape rather than put in a loop of hose. You should also see the way they attached the wire to the backstay, unbelievable!!! The list of poor installation practice on these boats goes on and on...lowest bidder??? Your tax dollars at work.

Eric