One fellow down the reply list sent you the Belden marine pamphlet, give that man a prize.
The short answer is the biggest **flexible** cable you can manage. But there are other considerations just as important; 1) Supporting the weight of cable. Clamp it at the top and bottom. Don't expect the connectors to support it. 2) Make sure it's not going to thrash around inside the mast. It will destroy the finish and the mast will rot from the inside out invisibly. One way to do this is support the cable from the bottom and let it 'Pile up" lightly inside the mast. This can be tricky because you want it tight enough to avoid rubbing. On one friend's boat we cut some plastic washers that looked like big external tooth lock washers. The coax, radar control cable, and mast light power went in the center hole and the outside was deformed to hold the whole assembly in place. These were installed every two feet by pushing them in place with a piece of PVC pipe (actually several pieces daisy chained.) The external notches insured air circulation and water drainage. . 3) Make sure that all water can drain. Don't wedge the cable with a piece of foam in a way that lets water collect. 4) Tape all connections with lots of overlap. I prefer to use self vulcanizing silicon rubber tape. Done properly, your metal parts will be *bright* after 20 years of exposure. If it's exposed to UV, put two layers of Scotch 88T over the silicon stuff that gets replaced every few years. A tape source: http://www.harmancorp.com/products/hightemperaturepaintmasks/siliconetape.aspx $8.80 for 12 yards X 1" Stretch it to twice it's length and wrap to cover the green center stripe. This stuff it tapered with a thick center and very thin edge. It will reliably cover and seal almost anything in one pass. Vernon Densler wrote: > > > I have been in a big discussion with the guys on my boat list about > the right coax for running up the mast for VHF marine radio. > > > > Keeping in mind that we are talking about a 70’ or so run going up the > center of an aluminum mast, in a salt water environment, and the radio > is limited to 25 watts. > > Also keep in mind that when off shore this is a life line and the best > possible send and receive is needed in an emergency situation. > > > > So given the criteria what is the best possible coax to use knowing > that thickness matters and bend radiuses may be tight? Others on the > list are saying “just grab any old 8X type cable and you will be > fine”. I say use something with very low loss and suggested small heliax. > > > > Any suggestions? > > > > Vern > > s/v Nirvelli > > KI4ONW > > -- mailto:[email protected] Oz POB 93167 Southlake, TX 76092 (Near DFW Airport)
