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Old 02-06-2016, 16:05   #16
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Re: Can you identify this antenna?

Keel stepped. Has reasonable access from the base.
Main concern is a tabernacle (hinge) near the deck. I think it has a hole in the plate which everything passes through. Thinking about it.
Its probably best to pull from the base as that way i can leave the factory fitted and sealed plug at the top and cut the inboard plug off for easier access.

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Old 02-06-2016, 16:30   #17
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Re: Can you identify this antenna?

Gotta be a rubber duckie for a marine VHF, and if someone did that (given how cheap 3 and 6 dB marine atennas are) they undoubtedly used cheap coax as well. Rip it out. If that masthead position won't support a 14' 6 dB antenna (I doubt it will) compromise on a 3 dB stainless whip. Positioned that high up it'll perform just fine. High quality RG-8 or RG-213 (same size, but waterproof) is well worth the investment.
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Old 02-06-2016, 18:08   #18
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Re: Can you identify this antenna?

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Mcos.
We have checked it using a multi meter and hooked up a whip to it which worked perfectly. So we can confirm there is a short somewhere.
You cannot measure an antenna with a multi meter. Most antennas (the good ones) show a short. That is because there is an induction that shorts it for DC. For VHF signals that induction is not a short but a high resistance. But replacing it for a full size antenna would be a good idea anyway.

If you want to check your cable for shorts, disconnect it at both ends first. Other than that you need specialized equipment like an SWR meter to say anything sensible about the antenna installation. A good indicator is the colour of the copper inside the cable (cut a short piece off). If it is black the cable is gone and should have been replaced a few years ago. If it is green, it should have been replaced a decade or more ago.

Instead of RG213 try a modern low loss cable like, for example, H155. It has similar loss characteristics as RG213 but has the same diameter as an RG58.
At the same time it is more rugged than aircell and other hollow cable types. Tremoflex would be the low loss solution for professionals but that may be a little overkill for yachts.
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Old 02-06-2016, 18:36   #19
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Re: Can you identify this antenna?

Cable coper is definitely black.Must have been cheap rubish..

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Old 02-06-2016, 20:28   #20
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Re: Can you identify this antenna?

replace it with a s/s whip the corellas wont eat it probably easier from top down as you can hang cable rather than having it all over the deck just replaced mine was easy with mast on the ground good luck
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Old 03-06-2016, 14:36   #21
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Re: Can you identify this antenna?

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Cable coper is definitely black.Must have been cheap rubish.
No, it means it wasn't properly sealed at the ends anymore. The connectors are not waterproof so you need to tape the cable ends and the connectors. Best is self amalgamating tape but that is not UV safe so you need to tape it again with UV resistant tape.

Then you need to inspect the connector's taping at every opportunity and at least once a year. Once water gets in to the coaxial cable it is useless. When the copper has gone black or even green you are too late and it is best to replace the lot, cable and connectors. Even if the cable is black at the ends only, you probably have water in it all the way.

Given the costs of 15 yards of cable (and an perhaps an antenna) I would not compromise on safety and replace the lot at first suspicion. Maybe only to put my mind at rest, but that's worth something too.
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Old 03-06-2016, 23:25   #22
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Re: Can you identify this antenna?

Quote:
Originally Posted by Hoohaa View Post
Keel stepped. Has reasonable access from the base.
Main concern is a tabernacle (hinge) near the deck. I think it has a hole in the plate which everything passes through. Thinking about it.
Its probably best to pull from the base as that way i can leave the factory fitted and sealed plug at the top and cut the inboard plug off for easier access.

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You have had lots of good advice, won't add mine to the confusion!

But could you explain how you have both a keel step AND a tabernacle? That seems self contradictory to me!

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Old 04-06-2016, 06:39   #23
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Re: Can you identify this antenna?

The boat was built in Perth Western Australia. All Yachts in Perth have to be able to lower there mast to pass under the Fremantle bridge.


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