RE: [Repeater-Builder] Re: Best coax for marine use
We are talking large sailboats going off shore and staying in places with little to no spare supplies. This all started with a friend that is in the Caribbean and has had both of his radios fail and can't even make it to talk to the marina's and bridges. Turns out that one of the radio problems is somewhere in his coax and so he has to replace the cable. Something that you don't want to have to replace that often. He does have HF but that doesn't do any good for bridges and most of the Coast Guard traffic is on VHF. I am very interested in this not only to help a friend, but within the next few months I need to replace my coax and antenna. I would like to be able to run my 2 meter off of the same setup but unless I can find a really wide band antenna I don't see that happening. Maybe I would be better trying to run UHF and Marine VHF off of 2 antennas with a diplexer at the top of the mast. But that is a whole different discussion. One thing I am going to suggest to these guys is that anyone who doesn't have a spare antenna should at least make a ladder line J-Pole cut to the marine bands to be able to hoist it up the mast in an emergency. Vern KI4ONW "But how far can you get on the less than 9 watts you will have left after using a cable with that much loss?" Pretty darn far! In the "old" days, I used to mess with the old "packset" (pre handheld) radios that were available at the time. I had one GE, pre "PortaMobil" that was rated at 250 milliwatta output on 150Mc that I converted to 2M. I used to talk consistently and reliably from my home on the SF Peninsula to a station in Sacramento, about 98 miles away. The packset was connected to my base antenna but that had about 80 feet of RG8 from my shop to the tower. I was high and the path had little or no obstruction but it is still not an over-water path. It doesn't take much power under those conditions. If it were me, unless I had a VERY large powerboat, I would stick with a marine handheld with both NiCd and Alkaline batteries available. Tom DGN
[Repeater-Builder] Re: Best coax for marine use
"But how far can you get on the less than 9 watts you will have left after using a cable with that much loss?" Pretty darn far! In the "old" days, I used to mess with the old "packset" (pre handheld) radios that were available at the time. I had one GE, pre "PortaMobil" that was rated at 250 milliwatta output on 150Mc that I converted to 2M. I used to talk consistently and reliably from my home on the SF Peninsula to a station in Sacramento, about 98 miles away. The packset was connected to my base antenna but that had about 80 feet of RG8 from my shop to the tower. I was high and the path had little or no obstruction but it is still not an over-water path. It doesn't take much power under those conditions. If it were me, unless I had a VERY large powerboat, I would stick with a marine handheld with both NiCd and Alkaline batteries available. Tom DGN --- In Repeater-Builder@yahoogroups.com, "Vernon Densler" wrote: > > But how far can you get on the less than 9 watts you will have left after > using a cable with that much loss? > > > > From: Repeater-Builder@yahoogroups.com > [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Eric Lowell > Sent: Tuesday, November 24, 2009 12:39 PM > To: Repeater-Builder@yahoogroups.com > Subject: Re: [Repeater-Builder] Best coax for marine use > > > > > > The only issue I would have with Heliax is the possiblity of cracked and > broken solid conductors due to vibration and repeated flexing. If I were the > vessel owner, I'd use a good grade (Belden or equivalent) of RG-8 (X if you > want). There are not a lot of terrain features out there. I'd think you could > talk quite a ways on 25 watts at 70 feet HAAT. 75-100 miles? > > > > GL, Eric > > > Eric Lowell > Eastern Maine Electronics Inc. > 48 Loon Road > Wesley ME 04686 > eme@... > www.satnetmaine.com > > > > _ > > From: Vernon Densler > To: Repeater-Builder@yahoogroups.com > Sent: Tue, November 24, 2009 11:17:45 AM > Subject: [Repeater-Builder] Best coax for marine use > > > > 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 70â 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 âjust grab any old 8X type cable and you will be fineâ. I say use > something with very low loss and suggested small heliax. > > > > Any suggestions? > > > > Vern > > s/v Nirvelli > > KI4ONW >
RE: [Repeater-Builder] Re: Best coax for marine use
I have an emergency antenna and wouldn't go anywhere without it. Also have a hand held. From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Douglas Sent: Tuesday, November 24, 2009 3:55 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: Best coax for marine use All of these ideas (and they are just ideas, with some experience put behind it) have merit. Just to think of the bigger picture, you may want to have a spare antenna somewhere on the boat so that if you are de-masted, you can still communicate. Your range will suffer only a bit if you still can talk well from 20 feet above water (or whatever you can muster). No matter what coax you use, and what antenna you have, you still have a failure point and a spare is the only recovery at sea. Depending on the boat size, you can either mount one, or have one that clamps to a side rail, or whatever - just have a spare. The antenna, no matter which type of coax or even antenna, is more likely to fail before the radio. Just my $0.02 worth Doug in Seattle --- In Repeater-Builder@yahoogroups.com <mailto:Repeater-Builder%40yahoogroups.com> , "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 >
[Repeater-Builder] Re: Best coax for marine use
All of these ideas (and they are just ideas, with some experience put behind it) have merit. Just to think of the bigger picture, you may want to have a spare antenna somewhere on the boat so that if you are de-masted, you can still communicate. Your range will suffer only a bit if you still can talk well from 20 feet above water (or whatever you can muster). No matter what coax you use, and what antenna you have, you still have a failure point and a spare is the only recovery at sea. Depending on the boat size, you can either mount one, or have one that clamps to a side rail, or whatever - just have a spare. The antenna, no matter which type of coax or even antenna, is more likely to fail before the radio. Just my $0.02 worth Doug in Seattle --- In Repeater-Builder@yahoogroups.com, "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 >
[Repeater-Builder] Re: Best coax for marine use
I would Suggest looking at either aandrew FSJx-50 or LMR 3/8" or 1/2" heliax type cable (100% solid shield) and if available a direct burial or underground type jacket for additional water infiltration protection. Go the the home pages or either mfg. to get full specs and min. bend radius. Doug N3DAB --- In Repeater-Builder@yahoogroups.com, "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 >
