VHF Antenna/coax routing

[goose327]

I finally got my antenna in the mail yesterday. I want to mount it atop the mast and run the coax down, inside the mast. It looks like there is alot of "stuff" in there already, 2 halyards, masthead light wires, ect.. How much trouble am I looking at? Any pointers?

[sailingdog]

Is there a conduit for the wiring already setup?? If not, it might be wise to add one now... and simplify your life for the future...

[cpcohen]

If you don't want to run a conduit:

Put three plastic wire ties along the coax, every few feet. The ends will stick out and hold it more-or-less in the center of the mast. You don't want it going flip-flop when the boat rolls.

A conduit is better, if you can manage it.

Charles

[camaraderie]

Goose...good advice on the wire ties. As far as running the cable...it is easiest if you first run a weighted messenger string line down the mast and then pull the coax through with that. Also...when you drill the hole for the wire feed, put in a bushing to avoid the aluminum cutting through the coax BEFORE running the wire!

[sailingdog]

A conduit will help prevent the coax cable from fatiguing far more than the wire ties will IMHO. It will also prevent the halyards from possibly catching or chafing on the wire ties...

[sailaway21]

Also, if you're drilling a hole in the mast, start with a small pilot hole and then drill the hole to size at an angle. This will allow your cable to come out more parallel to the mast. You can still use the rubber bushing for chafe with a little finesse.

[sailingdog]

You definitely want some sort of protective covering over the cut edges of the mast, to protect the cabling... either a grommet or bushing of some sort. Make sure that it will fit over the cable fittings, if you have installed them before running the cable. Generally, I recommend that you run raw cable and then attach the fittings afterwards, so that you can minimize the size of the holes you have to make.

[yzlian]

perhaps you know this already - make sure the metal sheath in the coax covers the ENTIRE length of the cable when installed, right up to the connectors and inside a little bit if you can manage. A few weeks ago I was working on such a cable, and failed to cover the last 1/2 cm of cable at the connectors with the metal sheath (which I had cut away...), and I got absolutely NO signals from the antenna to the radio. Then I figured it out, and covered the last 1/2 cm with several layers of...aluminum foil then taped-covered, and it worked fine. The cable is only a bridge, placed inside the cabin wall, and so the aluminum foil plus tape is good enough though not professional.

Joseph

[sailingdog]

yzlian-

You're lucky you didn't fry your radio. Most VHF units don't like to broadcast without a proper antenna attached.

[Wayne25]

Goose:
If a strong signal is important to you, Use RG8U coax. It has half the loss of the so called low loss RG8x coax. No matter what you use, you should strain relieve the coax. I did it by running a 5/16" double braid line inside my mast and tied it off at the mast head. I used nylon cable ties going through the braid line every 2' for the strain relief support. But I don't have internal halyards. You could probably use the conduit as a strain relief in the same way. You can use a "Blue Sea Cable Clam" at the deck for the through deck fitting. That way the PL259 connector you soldered on your coax can come through the deck easily when you take down your mast each launch. http://www.westmarine.com/webapp/wcs...6511&ref=81902