Running a new coax to mast bse

[Richard Bryer]

Latest job on the list- When I took the mast down this year, I found that the shield layer on my VHF cable is separated as a result of almost 30 years of being bent around when connecting/disconnecting when the mast is taken down or put up. That is why I was having intermittent problems with the radio in the last few months I guess.

I have attached a picture that shows the wires coming thru the caulk filled PVC thru the deck. The break is almost at the caulk. It means running a new cable from the radio to the connector. My questions:

1. is it possible to loosen the old cable in the caulk and pull a new cable back down from the top to save taking the teak covering off below etc.

2. The messenger line seems to be seized in the caulk- anyone been able to free it and where is the other end- in the "beam in the cabin top or down at the bottom of the post?

What is the routing of the coax in the cabin- thru the beam and over to the starboard side or down to the bottom of the post and under the sole?

I would be very thankful for any tips/advice etc from some one who has done this- Thanks in advance

 

[Allan12210]

Hi Richard,

On mine back in 1996, when I had the original compression post support, the coax went down the standpipe, then turned to the port side in a groove hogged out in the crossways piece of lumber up in the overhead beam. You can see this in the picture. The coax and messenger line was threaded through a piece of water line under that wood (which you may also be able to see). The coax and string continued in the beam over to the side where I believe it follows along by the reading lights and AC outlets to the nav station. Taking out the reading light will allow you to confirm this and pull the string in steps rather than trying to do it all in one step.

Looking at your setup makes me wonder if you could pop those other connecters apart and pull that standpipe out, to be replaced with a new one. That way you could slit it open and get the wires and messenger away from the caulk.

I hope this helps.

Allan

 

[Claude L.-Auger]

Hello Richard,
I confirm Allan's routing of the VHF and other wires is the same on mine. Through the traverse beam down by the reading lamp on port side, then along port side, running near the 110V outlet. Removing the vertical PVC tube that hides all the wiring will give you a fairly good grip on the VHF coax. Once I had the thru-deck caulking and chase pipe removed, I soldered the new coax to the old one on deck, then pulled first from the cutaway of the pulled-out reading lamp (with someone feeding the coax from the deck), then from the cutaway of the pulled-out 110 outlet and finally from the area where all wiring comes out. After soldering, tape tightly with electrical tape and smother with dish soap to make it slide easy as there are lots of hidden hooks in the FB. The person feeding can add soap now and then. It will make the job much easier and will dry out.

When I did the compression post I replaced the beam with aluminum bar stock in which I created a slot. I think Allan's idea of replacing the chase pipe will make it easier for you if you don't need to do the compression post. I am including a pdf description of my compression post and traverse beam job as it has a lot of pictures which may be of some help.

BTW, I have cut a window about 8" from the base of the mast. Makes connecting and disconnecting all wires much easier when stepping or unstepping the mast every year. Good luck.

 

[Richard Bryer]

Thanks, Allan and Claude- the pics are a big help. The hint about removing the PVC tube makes good sense. I will keep you posted.
I have archived your pics on the mast base replacement, Claude- might come in useful in future years.

I did cut an opening in the mast- mine is a bit lower than 8"- but it has served us well in the annual mast removal . Much safer for my wife's fingers!

 

[Richard Bryer]

Well. Spent the afternoon tracing where the coax goes, removed the reading light and the AC receptacle. Dug out some of the caulk and freed up the coax at that point. Guess what- the co ax on my H34 (1983 but with small mast base) actually goes down the support post, across under the sole and back up through the aft corner of the vanity and up into the space that the AC receptacle opens into. When I could find the old coax in that opening- in one of those corrugated sheaths - and I couldn't in the reading light opening, I knew something was different. However the messenger line does come down thru the transverse channell and along the space by the AC box. So that is where I will run the new cable.

 

[Forrest15112]

I can't add much useful info on removing the old cable, but my expertise is on the cable itself. Since you're replacing it, I would like to suggest you look at Times Microwave LMR240. The specs are superior to RG8X which is what looks like you have now or RG58, which is even worse. LMR240 is only .240 inches in diameter ( hence the name), is very flexible, and reasonably priced. The size, cost, and loss, is a good trade-off for a typical marine installation. The standard jacket is designed for 20 years of UV exposure. LMR240-DB has a weatherproofing compound around the braided shield and foil which is supposed to keep the cable from deteriorating if the shielding is cut or damaged, or if the connectors aren't sealed well. There's a white version made too, if that's important. Good luck with the replacement and be sure to seal any exposed connectors.