im currently planning on putting my shack back (long story)anyway i purchased several runs of lmr cable for my set up,,if im short of cable and need to add on 10 or fifteen ft what should i do?
coax ?
- Thread starter cmed325
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I think I would just add enough of the same kind of coax to what you already have. That's about as typical as you can get. I would agree to stay away from the Radio Shack connectors. I prefer to use 'Amphenol' connectors. Also nothing particularly wrong with using a 'barrel' connector to join two pieces of coax. If that 'joint' is outside I think I'd weather proof it. Any difference from using one continuous run of coax? Sure, but not usually enough to make any perceivable differences.
- 'Doc
- 'Doc
ok,thnx,,how bout to connect a long wire to a ic r-75,,would lmr be the best way to go?
ka3jjz
Wiki Admin Emeritus
For a R75, LMR is way overkill. A good quality 58U or 59U will do just fine. And don't forget to waterproof the connectors with Coax Seal or a double layer of tape and a silicone compound. You don't want water in the line, which will ruin the coax
Mike
Mike
K
kb0nly
Guest
Coax seal sucks... And don't use silicone unless its 100% acid free also, otherwise your just asking for corroded connections and eaten away insulation. As far as coax seal that gooey crap is a nightmare to clean off after a few years of exposure, here is the method i use...
Self Amalgamating tape, also known as self fusing rubber tape, or splicing tape, it has a lot of names but can usually be found in the electrical isle of your local big box store.
If your splicing use a couple good quality connectors and a barrel. Take the self fusing tape and start about an inch before the connector and wrap tightly, just stretching it so its about 3/4 of its normal unstretched width, unless the brand you buy says otherwise this works the best on most of them, wrap it so that you also overlay it half the width of the stretched rubber tape and continue wrapping until your an inch past the opposite connector, then go back with a second layer same method as the first, then cut it with a knife or scissors and lay end down.
Now grab a roll of a 3m Super 33 or 33+ electrical tape and start before the rubber tape and cover it to the other end, and then back again with a second layer. You want two layers of tape over the two layers of rubber tape. The rubber tape is not UV resistant, so the electrical tape is just there to protect the rubber tape from UV. Now your done...
I have done this with splices and similarly for antenna connectors, electrical connections, you name it, and coming back years later i have sliced this open with a knife and it comes right off like a solid rubber shell and the connectors inside look like brand shiny new, no coax seal goop to clean off or messing up the threads of the barrel or the antenna's connector, nice and clean.
We use this method on all the repeater sites and never a problem with any connector wrapped like this up in the air on the top of the tower.
Self Amalgamating tape, also known as self fusing rubber tape, or splicing tape, it has a lot of names but can usually be found in the electrical isle of your local big box store.
If your splicing use a couple good quality connectors and a barrel. Take the self fusing tape and start about an inch before the connector and wrap tightly, just stretching it so its about 3/4 of its normal unstretched width, unless the brand you buy says otherwise this works the best on most of them, wrap it so that you also overlay it half the width of the stretched rubber tape and continue wrapping until your an inch past the opposite connector, then go back with a second layer same method as the first, then cut it with a knife or scissors and lay end down.
Now grab a roll of a 3m Super 33 or 33+ electrical tape and start before the rubber tape and cover it to the other end, and then back again with a second layer. You want two layers of tape over the two layers of rubber tape. The rubber tape is not UV resistant, so the electrical tape is just there to protect the rubber tape from UV. Now your done...
I have done this with splices and similarly for antenna connectors, electrical connections, you name it, and coming back years later i have sliced this open with a knife and it comes right off like a solid rubber shell and the connectors inside look like brand shiny new, no coax seal goop to clean off or messing up the threads of the barrel or the antenna's connector, nice and clean.
We use this method on all the repeater sites and never a problem with any connector wrapped like this up in the air on the top of the tower.
KC4RAF
Member
+1 with what KB0NLY
posted. That coax seal is nasty to clean. Electricians some time refer to that splicing tape as "snake skin" because of the thin film that's pulled off prior to wrapping. It's very rain, moisure proof when done right. Also follow his topping off with GOOD electrical tape,(again he list the best). Good luck.
posted. That coax seal is nasty to clean. Electricians some time refer to that splicing tape as "snake skin" because of the thin film that's pulled off prior to wrapping. It's very rain, moisure proof when done right. Also follow his topping off with GOOD electrical tape,(again he list the best). Good luck.
If the line is after the coax switch - you can use mini 8 - because there is not a lot of loss in 10 or 15 feet - especially if it is in the shack and the frequency is below 150 mhz.
Anything outside - it is best to use the proper length of cable and not use a barrel connector - the more connectors you add the more loss you build into your system and the more likelihood of having a problem somewhere down the road.
If the cable is free - which I am guessing it is - then use what you have and buy what you need.
Don't be cheap about the cable - it is the most important part of the equation.
It will make or break a good antenna system set up.
Make sure if it is used to cut a foot or so off each end and check it - if it is junk - keep cutting back until you find a good section.
Don't just use it because it is the right length.
I chased a similar problem for the last two months on my 10 / 11 meter radio.
The original piece worked - although it was a cheap piece of radio shack coax.
There was a split in the jacket and it worked a couple of times and then the shield burned off - high power and all and the fact that the radio shack wire does not have a full shield.
I then cut the offending piece off and in a hurry - due to rain, put in another crappy piece of wire.
It worked a couple of times and then quit.
I took it off and put another piece of wire between the antenna and the piece running into the house and now I have a fairly good signal - other then a couple of gremlins every now and then.
It doesn't pay to get in a hurry and it doesn't pay to use something that someone else was throwing away or selling cheap. People normally don't get rid of something unless there is something wrong with it.
Anything outside - it is best to use the proper length of cable and not use a barrel connector - the more connectors you add the more loss you build into your system and the more likelihood of having a problem somewhere down the road.
If the cable is free - which I am guessing it is - then use what you have and buy what you need.
Don't be cheap about the cable - it is the most important part of the equation.
It will make or break a good antenna system set up.
Make sure if it is used to cut a foot or so off each end and check it - if it is junk - keep cutting back until you find a good section.
Don't just use it because it is the right length.
I chased a similar problem for the last two months on my 10 / 11 meter radio.
The original piece worked - although it was a cheap piece of radio shack coax.
There was a split in the jacket and it worked a couple of times and then the shield burned off - high power and all and the fact that the radio shack wire does not have a full shield.
I then cut the offending piece off and in a hurry - due to rain, put in another crappy piece of wire.
It worked a couple of times and then quit.
I took it off and put another piece of wire between the antenna and the piece running into the house and now I have a fairly good signal - other then a couple of gremlins every now and then.
It doesn't pay to get in a hurry and it doesn't pay to use something that someone else was throwing away or selling cheap. People normally don't get rid of something unless there is something wrong with it.
That's what I found on the on a coax on my tower hwen I moved in. Original owners put it up 15 years before. Connector underneath was as shiny as the day it was born.
K
kb0nly
Guest
Its amazing isn't it??
If the stuff is done right its water and air tight and it lasts! I took a silver plated PL-259 and wrapped it in the stuff, two layers, and two layers of Super 33 and buried it in a flower pot outside one spring on a bet, almost forgot about it until the following winter and we dug it out and cleaned the dirt of and then cut it open, looked like new! Guess i won that bet eh?? LOL
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