CB Gurus please help

[Nick]

Ok so I installed my CB yesterday and when I tried to 'tune' the antenna with an SWR-meter it read in the read for both channel 1 and 40. So I figure ok I'm an idiot I'll try it out any way and it worked with my friends CB for about 1 mile. However, when ever I use anything electrical (turn signal, heater, power windows) it comes through the CB.

So my question is what did I do wrong and how do I fix it and throwing myself in front of a bus is not the answer I'm looking for, although at this point it may be an option.

Specs:
1996 Cherokee Classic, I-6
Optima Yellow top
Cobra 75 WX ST All-in-handset Mobile CB
Firestik II 4' Antenna (Model: FS4)
Firestik Adjustable, Stainless Steel Vertical Door Jamb Mount
(Model: SS-204A to accept PL-259 connection)
Astatic RG-8X 18' cable w/ PL-259 termination on both ends

Set Up:
Remote Mount under the passenger side dash (under glove box
where fake speaker grill is)
Power wire connected to spade terminal and plugged into
the "acc" slot of fuse box near the brake pedal.
Ground wire ternimated with ring connector and mounted
between the screw and metal frame of the dash on the passenger
side (the screw on the botton corner facing vertically)
Antenna Mount mounted to the body behind the passenger side
tail light.
Cable run under the passenger side interior moulding with the
slack layed flat in cargo area under the carpet (I at least new not to
coil the excess to avoid an "RF-choke")

 

[Urban Redneck]

I had this problem when I installed mine. What I ended up doing is running the power for it right from the battery. Nothing beats clean power.

 

[Tom R.]

If that doesn't work try a different ground. Don't forget to test it using a couple of the middle CB channels, too.

 

[Nick]

I was told that running power from the battery can cause noise because of diodes in the alternator?????? Does that make any sense.....

 

[Urban Redneck]

I was told that running power from the battery can cause noise because of diodes in the alternator?????? Does that make any sense.....

If it is coming off the battery there is nothing between it and the battery, as long as you run it right from the positive terminal. The ground issues is also a concern. Make sure nothing else grounds to the ground for the CB. Bad or shared grounds can cause RF.

 

[Nick]

Thanks for the help I'll try it out! :yelclap:

 

[avsno2000]

Most of the time that would be a grounding problem try another spot if you had'nt already done so.

 

[bburge]

You should still fix the SWR problem...

Firestik Tech

They have good docs on this sort of stuff...

bburge

 

[Nick]

So I've added a grounding wire from the antenna mount top the body changed the remoute CB mount ground and ran the power lead to the battery and now I have engine noise :dunno:

I ran over the Firestik tech articles prior to installing the CB what to do please help............

 

[DaffyXJ]

SWR is adjusted by shortening or lengthing (Usually shortening) the cable length. I installed mine and ran a solid 3 on the SWR. Cut a foot of excess off the cable and I had 1.2 across the board. Tom is right, check SWR in a mid range channel.
On mine with a 48 inch whip I have 5 mile range. Antenna mounted to top of rear hatch.

Pick a new ground spot and install an AC shunt, (Line filter) on the power side.

Engine noise is indicative of bad plug wires. Before you buy resistive spark plugs or new wires, Put the power back in the cabin and add a line filter if a new ground doesn't fix it. Remember, shorter wire runs are better.

Derik

 

[RTicUL8]

I tried putting my CB antenna mount at various locations on my Jeep - each time checking SWR. There were two spots that provided the best signal: on top of the roof, and on the top of my ARB bull-bar. I found that when the antenna is beside the body of the vehicle that it drastically cuts down on performance.

 

[old_man]

The engine noise is comming from the alternator. Go to Radio Shack and they sell a noise filter kit. It consists of a inductor (choke) and a capacitor. They are commonly used on sterios and CB's.

 

[btl_fed_xj]

Definitely roof mount your CB if you can. You'll get a heck of a better signal if it's up there, something about the signal being able to reflect off the roof. As for your noises, does the wire you are using have any small cuts or nicks taken out of it. Also where are you routing the wire from the engine bay into the cab? It should be nice and neatly tucked around some of the other wires and ideally I would also put it in split tubing to give it that much more insulation and protection. (there's a reason the use that stuff at the factory). I ran my CB power source off the terminal that goes into the fuse box.

Good luck man,

Jamie

 

[Nick]

Thanks guys,

I just got back from wheeling in Nova Scotia and it worked well enough there, but I'll try the suggestions out.

Cheers,
Nick

 

[sjx40250]

The best SWR readings will be obtained when the ground plane is the the most evenly distributed around the antenna. That is why the roof works the best.

Another considerations is how much ground plane is there in each direction. For example, if the Antenna is mounted near the windshield, you should get the best reception/transmission towards the rear. If the antenna were mounted near the rear hatch, the r/t will be best towards the front.