Where to route CB coax cables?

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SixPointTwo

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I'm mounting a CB and whippets on my truck. Whips are getting mounted to the toolbox.
Where did you guys run your coax cables?

Is there a hole with a grommet under the seat or something, where I don't have to drill a hole through the back wall or floor of my cabin? This is on an extended cab.
 

IOWNJUNK

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Drill a hole in cab and bed, make it big enough to run coax thru, do not forget grommets. If you ever sell or get rid of cb you can always plug holes with plastic plugs, never know you drilled holes.
 

19trax95

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There should be a grommet by the pedals but that's a long way to run the cable. I just drilled a hole in the cab. I used a grommet and put silicone around it. I wish I would have gotten the cable with the removable end so you only need to drill a small hole. But it was out of stock.

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IOWNJUNK

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Cable with removable end.......... Now ya tell me! Have to look for one of those next time.
 

great white

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I popped a drain plug out of the floor in the drivers side ext cab portion and installed a big rubber grommit to bring in my coax.
 

magimerlin

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^^^^^ will be using the same one here soon....

On a different note though.. Do not forget to ground your cb antenna mount real well. Truck boxes are not really grounded that good and I bet no one gets to bare metal on there bed rails to mount their boxes.. Just run a good size wire from the mount to the frame rail and you'll be all set...


Sent from what use to be a great country.
 

great white

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^^^^^ will be using the same one here soon....

On a different note though.. Do not forget to ground your cb antenna mount real well. Truck boxes are not really grounded that good and I bet no one gets to bare metal on there bed rails to mount their boxes.. Just run a good size wire from the mount to the frame rail and you'll be all set...



Sent from what use to be a great country.


Actually, you want strap braid since you are building an RF ground, not a DC ground.

Different principles.

RF is "skin effect" where DC ground travels the cross section of the wire. The wider the strap the better.

Also RF ground your box to the frame on all four corners.

If you want to do it right and maximize your transmission, ground hte box at all 4 corners, then bond the box to both rear corners of the cab then at least the two front corners of the cab. Finally, at least one strap near the rear of your exhaust system.

The exhaust has a reason: if you think about it, it's like a big antenna. Attached at the engine and then one long steel pipe (antenna) suspended in rubber right out hte back of the truck. It "fights" with the intended antenna and can induce noise. One simple braided strap near the back bond it to the truck and turns it from and antenna to a piece of the chassis and gives the antenna more (for lack of a better term) "ground plane"...counterpoise might be closer to the truth.
 
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IOWNJUNK

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Any truth to the coax/ant length being in 3's. Or divisible by 3? Not sure if I'm wording that right. Something about a CB wave being 3 feet and you should try to keep your total cable and antenna length in increments of 3'. IE: 21' coax and 6' antenna.


One of those things ya hear growing up that always sticks, wondered if there was any truth to it.
 

great white

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Any truth to the coax/ant length being in 3's. Or divisible by 3? Not sure if I'm wording that right. Something about a CB wave being 3 feet and you should try to keep your total cable and antenna length in increments of 3'. IE: 21' coax and 6' antenna.


One of those things ya hear growing up that always sticks, wondered if there was any truth to it.

Nope, myth.

I hazard to even through the number out, but the "magical length" people think for cb (27Mhz) is 9 feet. Total bunk.

The issue is the SWR. SWR is tuned by the antenna, not the coax. If changing the coax length changes your SWR significantly, you've got problems.

The required length of coax for a good mobile installation is just the amount required to run from the antenna to the set with no sharp bends or curves.

If you buy a length with pre-installed ends and it is too long, that's no problem either. Just make sure you don't coil it up in a bunch of loops. What that does is make an RF coil that behaves like a choke and reduces your signal going out and coming in. excess cable should either be loosely laid in out or if you must coil, make a figure "8"....
 

IOWNJUNK

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Cool, thanks for the info. I'll keep that in mind on my next radio.

One more question. Does that same info go for a VHF radio as well?
 
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