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VHF antenae routing

Started by mgoller, January 09, 2006, 03:54:41 PM

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mgoller

I started this topic because it deserves its own spot.
My boat came with the antenae mounted atop the mast.  Someone did a good job.  It is a shakespeare and it looks like it belongs there so I never studied it much.
The antenae cable does run through the mast and must have been pulled through with pieces of sytro foam or something because I have never heard a rattle.  Actually, I must be lucky, because nothing at all rattles anywhere.  I get a whistling from the rigging that tells me it was time for reefing.
The antenae comes out from a hole near the bottom of the mast maybe 1.5" up from the bottom.  There is enough length and a connector that I can connect it to the cable from the cabin.  There isn't a lot of excess.
The hole in the cabin top is next to the factory mast light fitting.  It is caulked with white caulk.  Honestly the only time I ever notice this is when I am raising or lowering the mast.  Where the hole in the mast is I do not believe compromises the integrity of the mast at all.
I also have a mast top light.  The wiring for this was probably pulled through when the antenae was.  It also has a connector and goes through with the antenae into the cabin.
From there all the wiring runs down the front of the compression post, and works its way down and through the starboard berth tunnel and to the battery compartment area where it is routed to the circuit board.
I do get very good reception on the VHF with it mast mounted.
By the way you no longer need a license to transmit on VHF so this may be a good way to keep track of your shore party with the hand held VHF radios.
My kids call me when its time to come home.
I'll take a picture of the mounting for the antenae and the hole.
I also think having a mast top mounted anchor light makes a lot of sense.

With the four circuits available I have divided them this way
circuit 1 - accessories - depth finder, 12 v receptacle, water pump
circuit 2 - cabin - lights (individually switched) , VHF radio, cd player
circuit 3 - running lights
circuit 4 - anchor light, cockpit light

crbakdesign

Thanks for the rundown on the antenna and your 12V system.  The antenna I purchased is about 5 ft. long, with mount that bolts to a stern rail and also fits around the spreader.  That puts the tip of the antenna close to the top of the mast, without interferring with the windex.  SSoooo that's where it may work best.  I like the idea of adding a mast top light.

The CP-19 foredeck light midway up the mast works fine, but you can't see it too well from the stern.  During the warm summer days, we often spent weekends out on the lake, overnighting in some cove. Last summer a couple on a large powerboat died doing that when some kids drove through thier hull.  Apparently the boat had drifted out into the mouth of the cove, and the kids were rocketing in the wee hours of the morning. A mast top light would be easier to spot on the lake and even more so in coastal waters.

I also usually hang a bright kerosene lantern over the cockpit as well just in case the battery goes low during the night and always double anchor when out on the water at night.

Craig Weis

#2
Years ago I mounted my new VHF radio. With the mast still laying on the pulpits of Comfort and Joy and working from a ladder at the stern of the boat and trailer I...

1~Unbolted the cast masthead piece, pounded that out of the way and let it dangle. Some "light at the end of the tunnel" sort of speak.

1~From the side of the mast that the antenae is to be mounted on I drilled a small hole the size of the coaxial cable needed just below the cast aluminum masthead

[REMEMBER the cast masthead piece has a skirt that fits down inside of the mast...so drill below the skirt] 

for the 30" Shakespeare antenae. Later when the masthead is reassembled back into the top-O-mast, screw the mounting angle bracket for the antenna into the skirt using a tiny drilled hole and two selftapping SS sheet metal screws, ss washers and plenty of 3-M 5200 goop. Make certain the screws don't touch the halyards lines. Other wise pull out the screws grind them off and put them in again. I did.

2~Simply  drill at the bottom of the mast a second hole as far up into the mast as fingers can reach and push and fish 18 ga. door bell wire thru both holes.

[Door bell wire is one thick strand and therefore it is stiff enough to push thru the length of the mast]

Then fish that bellwire back up into the drilled coaxial cable hole at the bottom of the mast.

[REMEMBER Fingers are only so long so the lower hole is drilled only an inch above the top of the mast step mounted on the deck house roof. You don't want to cut the cable when the mast goes up]

About 25 foot of bell wire is needed and about 40 foot of coaxial cable is needed on a Com-Pac 19. 40 foot is more then need. cut off what is not used. The shorter the better.

3~Strip about three inches of insulation off the doorbell wire and drill a 18 ga hole clean thru the coaxial cable. Insert the doorbell wire into the drilled hole in the cable, bend the bellwire up thru the cable and tape it off with PVC electric tape and pull the end of the coaxial cable to the bottom of the mast and backtrack it thru cable hole at the battom of the mast.  Stop for now.

4~Next pick a place for the radio. I picked the mounting screws already in the cabin top that holds the handrail on the starboard side. Unscrew the acorn nut and washer. Mount the radio bracket and put the nut and washer back on. I had to drill one additional hole in the radio bracket to match two of the screws of the handrail. No big deal. No new holes in the boat overhead. Yet.

Since two pieces of connected coaxial are used...in the boat and up the mast.

5~Drill the Cabin top by the mast step for a coaxial cable connector. Buy the long one. And buy the one that is to be soldered. Install that with plenty of 3-M 5200. Solder on the female end for the cable coming out the bottom of the mast. Leave plenty of extra cable for slack when the mast goes up and at that point you can push a few inches of extra cable back into the mast. And seal that hole closed with 5200.

6~I started from the overhead mounted radio and drilled a hole as far up on the bulkhead near the overhead and fished coaxial cable down between the inner and outer bulkheads by the dropboard, past the backside of the factory mounted electric switch panel, behind the carpet on the hull, over the top of the starboard birth but under the cushion, thru the storage compartment walls, and up the backside of the compression post to the bottom of the long coaxial cable connector that was installed by the masthead step earlier.

[Figured out first where the cable is to exit the interior of the boat at the top-o-compression post and that will locate where the connector came out by the mast step].

Solder on another female cable end and screw that to the roof connector.

7~Solder on a female end for the radio and bring some power to the radio. Your done.

Took about one whole day to make it right and to make it look good. Since I have to live with this for years...don't be in a big hurry to do the job. The Windex was offset to the back of the top-o-masthead on a teak 'stick' far enough way from the antenae whip to spin 360 deg.

Radios that are VHF are line of sight. So 25 foot up the mast is the best location if you want to reach out and touch somebody. I talked to a 1000 footer in Green Bay who saw me on radar, 16 miles away. skip.

Damsel19

A rigging trick to keep wires from banging.  Long cable ties in a pattern around the coax before you pull it up the mast.  Dont cut the tails off and tuck em in as they go.  you end up with a buch of plastic stand offs that are flexable enough to alow for adding other wires later.  If you are rewiring every thing you can send them up bundled this way.  Even with seperate exit ports and heights with a litltle planning.

Craig Weis

Leaving the tails on an electrical 'zip strip' wire tie is a good idea. That provides a cushion.
I wrap everthing in the mast with pvc tape. I don't know why. I figured the pvc adds a ware layer to the insulation of any conductor. Plus it festoons any additional wires all together. skip.