Coax cables?

[slosurfer]

School me on coax cables!

My coax cable is busted right at the connector that goes into the back of the cb.

A) Can this be repaired by getting a new connector? If so, how can I do that?

B) If not, teach me about coax cables, and what should I look for? I have a cheapo radio shack cb and maybe a cobra 19ultra (I thought it was fried, but maybe it's still good), and I have a 4 ft. firestick mounted on the back.

I'm possibly thinking of buying a new coax cable and running that in the 4runner. Then if the cobra still works and my old coax cable can be repaired with a new connector, then I'll put those in the van and I'll only have to come up with the antenna.

[L33T35T Tacoma]

Hey Chris. check out walcottcb

I remember you were using the "ring" type mount" here's a new coax cord
http://www.walcottcb.com/firestik-mu8r18-2piece-18ft-ezinstall-single-coax-p-581.html?cPath=28_355_437

I'd recommend going with the straight plug on the bottom though, just a personal preference
http://www.walcottcb.com/rg8x-coax-cable-18-foot-length-most-popular-188xsr49-p-729.html
and get a normal stud
http://www.walcottcb.com/firestik-k4a-stud-mount-pl259-screwon-connection-p-247.html

my buddy built his whole CB system from this website, minus the radio itself. shipping was very decent also.

Also, if you want to get a quick disco, get this one
http://www.walcottcb.com/firestik-k1a-internal-locking-quick-disconnect-p-571.html?cPath=28_354

again, buddy has it and its pretty bad ass. the one i have sucks, makes a lot of noise when it moves around.

and i know you already have a spring, but I like the heavy duty spring compared to my normal medium duty spring.
http://www.walcottcb.com/jbc404-heavy-duty-stainless-steel-antenna-spring-p-257.html?cPath=28_354

the medium duty lets the antenna fly everywhere. the heavy duty held my buddies 4 foot firefly antenna solid

hope this helped

[CYi5]

I'd say google is your best resource, and I 2nd the walcott suggestion, they are the company I always order from for radio stuff.

[slosurfer]

Thanks Jason, I remember you told me a lot of this stuff at Pismo, but I couldn't remember it all. :laugh: I figured I could google it, but it's nice to hear from others with real world experience.

That's the disconnect that I have, and I thought I had the heavy duty spring, but my spring seems kind of weak (hence, my bungy corded antenna :laugh: )

What are the pro's and con's of those two types of connections?

[L33T35T Tacoma]

I just like the idea of a screw on connector.... good ground. I'm not sure how the fire ring is grounded; a secondary, loose wire?

[Crinale]

i bought my stuff from rightchannelradios.com .. they had good prices and a good selection of stuff as well. can always cross shop ;)

[corax]

For a CB, use coax that is rated 50ohms - this isn't anything you can actually measure with a DVOM or ohms meter, it's a measure of radio frequency (rf) resistance

Forget about needing 18', a cable that is a multiple of 3' or any of that false mojo - the correct length cable is the shortest amount it takes to go from your radio to the antenna

do not coil any excess cable into a loop - it acts as a "choke coil" and raises the SWR, in the Ham world antenna leads (coax) are usually sold without the end terminals on so you can trim to size without having extra

I've heard "foam core" coax is best, but I haven't heard an explanation why - take it with a grain of salt

make sure the chassis of your CB has a good ground (same goes for whatever your antenna is mounted to), run an extra wire from a convenient screw on the back cover to ground, the best grounds are braided wire not stranded (resists rf induction, stranded wire can act like an antenna and pick up rf), the cheapest braided wire comes from the outer shield of the coax you are replacing

[4x4mike]

I think a magnet mount antenna on the roof is hard to beat. In my experience the fiberglass antennas are hard to tune, can break and are heavy flopping around. My magnet mount just shills on the top of the roof and when I need it I put the antenna in it and call it good. It comes with the coax and there is no need for additional mounts.

http://www.wilsonantenna.com/lilwil.htm

[slosurfer]

Forget about needing 18', a cable that is a multiple of 3' or any of that false mojo - the correct length cable is the shortest amount it takes to go from your radio to the antenna

do not coil any excess cable into a loop - it acts as a "choke coil" and raises the SWR, in the Ham world antenna leads (coax) are usually sold without the end terminals on so you can trim to size without having extra


So, it sounds like I can repair my existing coax cable and I should actually cut it to fit anyways. I just need to find a new connector and figure out how to install it.

[slosurfer]

I think I just need one of these and to figure out how to install it.

http://www.walcottcb.com/pl259584-coax-connectors-4pack-p-1804.html

I also found this link which kind of explains what Corax was saying about the length not being important.
http://www.signalengineering.com/ultimate/coax_basics.html

[corax]

coax end install:
http://www.dslreports.com/faq/15751
http://www.dxzone.com/cgi-bin/dir/jump2.cgi?ID=14424
http://www.wiringdiagrams21.com/2009/08/12/rg6-coaxial-cable-to-rca-compression-connector-installation-and-schematic-diagram

[slosurfer]

Okay, so correct me if I'm wrong, I either need to solder a connection on, or I need a crimp connection, but that requires buying a special crimping tool?

[corax]

the solder connector is best -- next, I think, if you look around you might be able to find one that uses a threaded section to tighten onto the cable (not sure) -- final is the crimp on kind, no special tool required, a regular wire stripper should have the crimper you need (the two half-moon bits next to the red plastic handles)

http://www.repairclinic.com/dbImages/00000909/00274841.jpg

[CJM]

I say get a new cable, I bought my whole setup from walcott and was VERY happy.

Got the firestick II, no ground mount, 18ft no ground cable and a heavy duty spring and like it alot.

[L33T35T Tacoma]

Forget about needing 18', a cable that is a multiple of 3' or any of that false mojo - the correct length cable is the shortest amount it takes to go from your radio to the antenna


Firestik disagrees


Q Is the length of the coax cable important?
A We find that it is very important ... especially with high performance top-loaded antennas. Your safest bet is to use 18 feet (5.5 meters) coaxial leads on all of your CB installations.

Source: http://www.firestik.com/FAQ.htm

[slosurfer]

the solder connector is best -- next, I think, if you look around you might be able to find one that uses a threaded section to tighten onto the cable (not sure) -- final is the crimp on kind, no special tool required, a regular wire stripper should have the crimper you need (the two half-moon bits next to the red plastic handles)


okay, cool, all the pics I saw, showed some other crimper tool, I have one of those so that's cool.



I say get a new cable, I bought my whole setup from walcott and was VERY happy.

Got the firestick II, no ground mount, 18ft no ground cable and a heavy duty spring and like it alot.


I'm definately getting a new cable for the 4runner, but I'm thinking of repairing my cable I have now for Vanna. :thumbup:

Doesn't the type of connection on the antenna side of your coax cable depend on how/where your antenna is mounted? For example, whether or not your mounting surface for the antenna is grounded or not.

Here is the full extent of what Firestik says about the length:

About the length: This is a testy subject with many engineering types. They have argued with us on many occasions regarding this matter. They say that if your system is set-up properly that the length of the coax is irrelevant. We agree! However, mobile installations have so many variables that a perfect set-up is the exception, not the rule. One guy has a pick-up and another has a fiberglass motorhome. One wants the antenna on the bumper, another on the hood and a third on the roof. Few people want to drill holes in their vehicle so quality grounds are always a consideration. Because of the imperfect world, we almost always recommend 18' (5.5m) when our products are used. We do so with good reason too! At 18' the voltage curve has dropped back to the zero voltage point where the cable meets the antenna which reduces the reactance within the cable itself (a null cable if you would). It has been our experience that if the antenna location makes it somewhat out of sync with its surroundings, cable lengths that are not multiples of our 18' suggestion adds to the problem. To that, our complaining experts say, "Then the antenna should be moved!" to which we say, "You tell the guy with the $30,000 vehicle that he must drill a hole in his roof so he can use a 9' cable". We solve problems in the best way we can given the boundaries that the customer establishes.

On that note, when you have 18' of coax going to a radio that is only 8' away, what should you do with the other 10'? We recommend that you serpentine it like a skein of yarn so that it is 10-14" long and tie it in the center with a wire tie then tuck it away. Do not roll it up in a tight circle as this can cause it to act like an RF choke, which often times will cause system problems.

Other ways to wreck your coax: Wear holes through it, slam it in the door a few dozen times, attempt to splice it as you would a wire going to your taillight, tie it in knots or make real sharp bends in it.

For your information, all of our Fire-Flex coaxial cables have stranded center conductors, polyvinyl insulation and bare copper shielding in the 95% range. Even though we offer some cables that are not 18', we do so for the knowledgeable installer, who knows that if a problem shows up, he must exercise the 18' recommendation. All of our mini-kits and complete kits are packed with 18' cables.

[corax]

PL-259 is the standard connector end for coax, especially to the rear of the radio itself. Though I have (rarely) seen some smaller connectors used here and there on the antenna side, PL-259 is still the standard

Ideally you want the antenna in the center of the roof. The ground plane of the vehicle is what the radio signal "pushes against" in simple terms, so you want as much of the vehicle under the antenna as possible for maximum range. The vehicle itself won't really block the signal since each wavelength is ~11 meters, you would need something > 11 meters long to muffle/block the signal (by my understanding). If you can't roof mount, try to keep at least 2/3 of the antenna above the roof line

[slosurfer]

Yeah, I know about where the antenna should be mounted, I'm talking more about what it's mounted on, i.e. is it grounded or not (like if it's mounted on a fiberglass shell, or an aluminum mount, etc..) For some reason, I was thinking there were different ways to connect on the antenna side depending on if the antenna is grounded or not, or does that not matter?

The way my mount already is, I could easily just do one of those firestick firerings and I wouldn't have to buy anything else. I may switch to a cable that has pl259's on both sides and get the corresponding antenna mount as I kind of like that connection.