coax question

[thetez]

hey all

ive got a co-phased system on my truck which works amaizing, so i dont wanna hear go with this or go with that.

my problem is my coax got pinched on one of the sides and the copper weave was showing, it looked a little roughed up but not too bad, my CB still works fine, i am still getting out just as far ... i think.... i taped over the section... you think their may be a problem... i mean am i only hearing well because of the 2nd antenna? my swr meter wont tell me anythings wrong cuza the dual system... i just need help to make up my mind, spend money and replace the coax, or leave it since i dont think im having a problem...

[Truckerjo]

my swr meter wont tell me anythings wrong cuza the dual system

Not sure what you mean here.... Why not? most people hook both antenna's up and set SWR that away... The suggested way is to do each antenna separate then together.. So, no matter what you should know what you SWR is far as your meter goes being a dual set up or not....

i just need help to make up my mind, spend money and replace the coax, or leave it since i don't think I'm having a problem...

Replace it, many reasons why like water can get past the tape, or you have more damage to the coax then what you visibly can see ext..

[Nick352]

Well sir, there will obviously be a weak spot in the coax. You may need to replace this later. If it works fine, you should not need any other changes, just remember that it is now weak, and like TruckerJo said, moisture may be a problem. Keep an eye on it from time to time.

Semper-Fi
Nick

[kd5drx]

Originally Posted by thetez

hey all

ive got a co-phased system on my truck which works amaizing, so i dont wanna hear go with this or go with that.

my problem is my coax got pinched on one of the sides and the copper weave was showing, it looked a little roughed up but not too bad, my CB still works fine, i am still getting out just as far ... i think.... i taped over the section... you think their may be a problem... i mean am i only hearing well because of the 2nd antenna? my swr meter wont tell me anythings wrong cuza the dual system... i just need help to make up my mind, spend money and replace the coax, or leave it since i dont think im having a problem...

You said the copper braid is roughed up? is it still intact all the way around the inner dielectric. The braid serves 2 purposes one it is the ground. 2 it is a shield to keep unwanted RF out of the system as long as it is still in tact it will work fine but it may be more prone to interference in a RF rich environment and like the others said it may allow moisture in. The moisture can be stopped by a little RTV silicone sealant applies to the area then wrapping electrical tape on top of it for a water tight connection that way. Good luck and like they always say if it aint broke don't fix it.

[thetez]

Originally Posted by Truckerjo

Not sure what you mean here.... Why not? most people hook both antenna's up and set SWR that away... The suggested way is to do each antenna separate then together.. So, no matter what you should know what you SWR is far as your meter goes being a dual set up or not....

because the way its tuned, i cant find out a true swr, i will find out the overall of both antennas, you DONT check one antenna at a time in a co phased system and if you have the correct type of coax thats not even possible, (unless you hook it up right near the antenna which is ineffective.). so if ones great and ones not so great it may show up as somewhere in the middle,


But anyway, thanks for the answers all, i didnt even think about the silicon, which is funny cuz i use the stuff every day.

[Area904]

There are several ways to match co-phased antenna's besides the type of coax, including the length of coax and antenna spacing. Yes, you should tune each antenna individually, otherwise you have no way to determine their balance (most of your signal will go to one, not the other, and screw-up your propagation pattern). Yes, the overall SWR is most important to transmitter longevity and antenna efficiency, but individual antenna SWR is just as important as total (co-phased) SWR.

Use a single coax to check each antenna individually.... NOT the co-phased harness!

This is well-covered in books on antenna theory and is also my personal experience!

[Truckerjo]

Thanks for replying to that and not having to type it out...

[thetez]

Originally Posted by Area904

There are several ways to match co-phased antenna's besides the type of coax, including the length of coax and antenna spacing. Yes, you should tune each antenna individually, otherwise you have no way to determine their balance (most of your signal will go to one, not the other, and screw-up your propagation pattern). Yes, the overall SWR is most important to transmitter longevity and antenna efficiency, but individual antenna SWR is just as important as total (co-phased) SWR.

Use a single coax to check each antenna individually.... NOT the co-phased harness!

This is well-covered in books on antenna theory and is also my personal experience!

using a different coax can change the swr, that doesn't sound very efficient. you are testing both the coax and the antenna when you check for the swr, why test only 50% of what you are using? My antennas are mounted exactly the same on both sides, and i adjust both heights to the same length when i check them, their isnt too much play with that..