CB installation - Page 2

Schludwiller · 01-07-2002, 11:21 PM

I ran my power to the far left row of the fuse box in the open spot in the picture above. Can the guy with the SWR meter help you out? He must have installed his own CB, right?

DeFibVT · 01-08-2002, 01:30 AM

That is a blue flat blade female connector. It slides right over the pins. I taped the outside of it to insure it wouldn't touch anything else.:smoker2:

WhirlwindMJC · 01-08-2002, 06:40 AM

No, he just picked one up at a garage sale. I'm going to hook up with him sometime today (he has a habbit of sleeping in until very late in the day) and hopefully we can figure something out.

WhirlwindMJC · 01-08-2002, 06:42 AM

When you said you routed power to that open slot on the left row, did you have to pop a fuse in there to complete the circuit, and just stick in the pos lead, and connect the ground to any exposed metal in the body?

Blacsmythe · 09-12-2002, 11:49 PM

Hello everyone,I am a newbie on this forum.
I was attracted to the Pathy guy with the CB questions.
I am in the same boat as you.
To everyone else there is alot of good info here, i hope i can trade as much as you.

csquare · 10-22-2002, 12:24 PM

This might be lengthy, but I will give details on how to mount the antenna to get maximum efficiency out of the radio and antenna system.

First, any CB antenna requires what is known as a "ground plane". This is made of metal and is usually the chassis of the car/truck. The "through glass" antennas are cute but not very efficient. They can increase the SWR "standing wave ratio" to the radio. SWR is a percentage of power output (in watts) from the radio going to the antenna versus power being returned to the radio from the antenna. The percentage is measured as an example: 1:1.5 (read 1 to 1 ratio). If the first number is high than 3, there is no efficiency in the systems and all the power being put out from the radio is being sent back hince poor reception and transmission. An SWR meter is almost necessary for a CB installation, so better treck down to Radio Shack to get one. Enough on antenna theory though.

Now for the installation:
I would suggest either mounting the antenna on the roof because you have to most amount of metal there for a ground plane. Another key factory to performance is height of the antenna. The taller or higher the antenna, the further the range. There are some rack mounts antennas available, but aluminum is not a very good conductor for signal. A mag mount would do the trick for this. I would make sure you have a spring load on the base of the antenna so the antenna can flex back and forth if you happen to hit tree limbs, garages and the like.
The coax cable attached to the antenna is usually considered part of the antenna (no wise cracks), I mean tuning is taken into consideration for the length of coax attached to the antenna. If you cut or alter the original length of coax, the tuning will change and cause increased SWR (it's a bad thing). Any additional cable leeft over should be neatly coiled up and tucked away from other electronics as far as possible.

Power:
The other guys are correct, you should run the positive lead for the radio to the fuse panel and not to any other accessory port. The negative lead shouldgo either to a common ground or to the battery negative.

BTW,
I work for an antenna company and I am an electronic engineer so feel free to ask as many questions as you like.

Hope this is helpful to you guys.

Regards,
Chris

Schludwiller · 10-22-2002, 05:47 PM

Only thing I would add is that you can get a non-ground plane antenna if you want to mount it someplace without a metal plane underneath the antenna. Several of our members mount their non-grounds on their ARB bumper.

Also, every bit of information I've been given says that left over coax should NOT be coiled, but "butterflied" by using a zip tie or tape to bind the center of the coax. If you have different info, I would be happy to hear it.

csquare · 10-23-2002, 09:23 AM

"Butterflying" the coax would work if it was done losely. The binding at the center of the coax gives sharp bends which checng the dielectrical characteristics of the coax as well as the impedance. In simpler terms, this can increase SWR. The spacing between the center conductor and the braid (ground) in the coax should remain constant. When you put sharp bends or kinks in it, the dielectric (insulation between the center wire and braid) becomes compressed putting the two wires closer together. Physically and electrically this changs the characteristics of the coax thus the antenna itself.

Hope I didn't get too mombo jargenish.

Chris

csquare · 10-23-2002, 09:29 AM

I forgot to also mention that non-ground plane antennas (although convenient) are not efficient at the CB frequency (27 MHz). For short range communication they work fine, but remember, in my job I have to try to maximize the range and efficiency of the antennas I deal with so I will be geared more towards the ideal mounting and hardware.

I'm such a stupid biased engineer!!!!!

Chris

AerialViper · 10-27-2002, 04:12 AM

DeFibVT,
I was looking at your picture and was curious if the power shuts off on the fusebox when you turn your ignition key off. I have several accessories that I am installing and need a power source for them. I don't want to take the chance by wiring directly to the battery and accidently leaving them on and draining the battery. Thanks for your help!

VaderX · 10-27-2002, 11:01 AM

Why would mounting it to the arb be considered non ground plane. The bumper is metal and it is attached to the frame also metal. Would it require grinding the powder coat off or what.

Schludwiller · 10-27-2002, 12:15 PM

One. No metal contact. I remember XOC had forgotten to make metal contact on his non-ground and wasn't getting good reception. He fixed that pretty soon by removing some powdercoat.

The other (and this is just what I was told), is that there really isn't a good plane of metal out there to help direct the signal, so the non-ground was preferable.

IceChickenX · 10-27-2002, 01:32 PM

WOW this would explain why I'm having trouble with my CB in my other truck...Thanks csquare for the write up on the CB antenna install/checkout. When I get back home from my business trip, I can fix my CB (post purchase of a SWR gauge)

IceChickenX

csquare · 10-28-2002, 03:06 PM

Glad to help, especially since I have received so much help from here.
Just let me know how it goes and If you need any more help.
Good luck!!

Chris

nflxterra · 03-14-2003, 08:49 PM

another thing to remember is the location of the antenna mount. the output of the cb is in a circle somewhat if you locate the antenna to the front of the truck you are projecting a oblong cone more to the front of the truck, if you mounted it on the rear bumper the same would be true only the cone would be going behind the truck as i've read the ideal mount is one the roof where you would project and receive in almost all directions equally as this is you're transmit point.

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