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length of coax? attn: cb gurus.

Old May 29, 2009 | 07:37 PM
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Question length of coax? attn: cb gurus.

i have an 18' coax cable and it reaches the location of the cb, but its all out in the cab. i have no carpet, so i want to route it through the padding on the roll bars. thus said, does it matter the length of the additional coax? can i just add 9'?

tia.

-mikey
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Old May 30, 2009 | 06:46 AM
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Depends how you plan on adding the length. I've never seen a fitting is configured such that it adapts from terminal (the end that would have attached to the radio), to a female "coupler".
If you plan on soldering on an extension, care must be taken to keep the shielding all around the inner core. This keeps the interference away from the inner core, where the signal is carried, both outgoing (transmit) and incoming (recieve).
It may be cheaper to purchase a new, longer cable. No cuts, no repairs. Cable is cheap. Fittings are usually expensive. JMHO.
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Old May 30, 2009 | 07:15 AM
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Originally Posted by newt5005
... If you plan on soldering on an extension, ...
If by this you mean soldering a piece of RF cabling to a second piece to make it longer--this is not a viable option. The impedance lump presented by such a haphazard approach would clobber SWR. Either use proper RF connectors (which can be found, but the price may be high as you allude), or use a full length of one run of coax. If all else fails, you can solder two PL-259s, then use a "barrel connector" (fairly common adapter) to connect the two pieces. But, the best option because it gives the best performance in transmit and in receive is a full run of one length of cable with minimum connectors.

Speaking of cable: There's cable then there's cable. If you're fabricating this from scratch, buy good stuff. If you can see the white phenolic easily through the outer shielding, just say no. Unfortunately, many of the pre-made cables are very poor quality coax. Buy coax in which the shielding fully encloses the dielectric between the shield and the center conductor.
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Old May 30, 2009 | 11:24 AM
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Originally Posted by Mark Doiron
If by this you mean soldering a piece of RF cabling to a second piece to make it longer--this is not a viable option. The impedance lump presented by such a haphazard approach would clobber SWR. Either use proper RF connectors (which can be found, but the price may be high as you allude), or use a full length of one run of coax. If all else fails, you can solder two PL-259s, then use a "barrel connector" (fairly common adapter) to connect the two pieces. But, the best option because it gives the best performance in transmit and in receive is a full run of one length of cable with minimum connectors.

Speaking of cable: There's cable then there's cable. If you're fabricating this from scratch, buy good stuff. If you can see the white phenolic easily through the outer shielding, just say no. Unfortunately, many of the pre-made cables are very poor quality coax. Buy coax in which the shielding fully encloses the dielectric between the shield and the center conductor.
I second that......rather than using a barrel connector, it would be far better to just run a longer coax.....less chance of having another soldering job work loose. And yes, get some good coax....I forget exactly what it's called but I think it was RG8X, or Mini 8, was always good stuff.
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Old May 30, 2009 | 06:12 PM
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ok, so how about this: hXXp://www.walcottcb.com/procomm-30-coax-cable-removeable-pl259-308xn13-p-1086.html?cPath=28_355_437

30' Foot Coax Cable w. Removable PL259 Connector
Our popular 188XSR49 coax cable with the added ease of a removable "EZ-Install" Connector. 30 Foot length quality RG8X 50 ohm coax cable with hand soldered PL-259 connectors. 95% copper braid with weather boot. For single antenna installations.
Features

* Impedance: 50 Ω
* Length: 30 Foot
* Connectors: 1x PL259 (soldered), 1x PL259 (removable)
will i have issues with the longer length? every where i look it seems that if you dont use an 18' coax you will have issues with something.
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Old May 30, 2009 | 09:32 PM
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Originally Posted by mikeyfl
ok, so how about this: hXXp://www.walcottcb.com/procomm-30-coax-cable-removeable-pl259-308xn13-p-1086.html?cPath=28_355_437



will i have issues with the longer length? every where i look it seems that if you dont use an 18' coax you will have issues with something.
Well...you really don't want to go much less, but it's ok to go longer.....to an extent. BUT..30' is a bit much. Remember, there is a thing called "line loss", meaning, in a nutshell, the longer the coax you go, the more the signal is sucked up by the coax rather than to the antenna. And in small/cheap coax it can happen fast. That's why us HAM ops usually use the spendy big stuff or even, what they call, Hard Line. Minimal line loss at given frequencies. If I were you I'd just figure exactly what you need and if you don't want to solder the connectors yourself, I'm sure there's a electronic shop that will do it for you.
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Old May 31, 2009 | 04:35 AM
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Originally Posted by AK4Dave
And yes, get some good coax....I forget exactly what it's called but I think it was RG8X, or Mini 8, was always good stuff.
I would suggest Belden..
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Old May 31, 2009 | 04:39 AM
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Originally Posted by mikeyfl
ok, so how about this: hXXp://www.walcottcb.com/procomm-30-coax-cable-removeable-pl259-308xn13-p-1086.html?cPath=28_355_437
Shop around before buying anything from walcottt cb, you can usually do better price wise.....
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Old May 31, 2009 | 07:23 AM
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What about using the 30' and cut as needed?
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Old May 31, 2009 | 10:10 AM
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Originally Posted by Ridin' Dirty
Just go to freaking radio shack and get a barrel connector and get a hunk of coax. It's only cb radio, he's not trying to do EME, lighten up guys. Get cheap coax, after a year of Florida weather he'll probably have the pl259 that's outside so corroded he'll have to replace it again anyway. Line loss at 27mhz is so slight at that length he'll never notice. If he uses Radio Shack cable (rg58) and at 30 feet and a 1:1 swr, his loss will be about .6db and if he has a barrel connector in line that's an extra .05db at resonant frequency, so now we got a total of .65db of line loss at frequency. WOW that's really worth worrying about.....not!
Well......yeah, but he might have a hard time hiding that big ol' barrel connector in a certain place. So why not get just what he needs of some good Belden and be done with it? Sure 30 feet would be "ok", I was also just tryin to keep the guy from having to hide and extra 10' of cable if he only needs 20'. Besides, cheap coax sucks, even if it is just CB.....try bending that crap around a sharp corner and all kinds of things can happen.
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