So I just installed a CB in my 4runner, the antenna is at the back, but when the squelch is turned down, the cb puts out engine noise, the frequency fluctuates with the engine RPM. what have I done wrong? is this normal?

 

bad ground

 

I'm going to say bad ground too. Make sure you scrape away some paint where the ground cable contacts the chassis.

 

Also run directily to your battery posts and add a fusible link on the positive side

 

I've had the same problem, I ran a twisted pair straight to the battery posts and it didn't help. Next I tried an inline noise filter and that got rid of about 75% of it but still have some.

 

calibrate SWR. make sure it's less than 3. or check your grounds. and also check your antenna mounting. how far above the roof does it stick up???

 

Every CB I've seen picks up some engine noise.

I got a cobra night something or other... sorry its way to late and im way to tired to remember ANY specifics atm...

anyway, mine picks up noise from the air fan more than anything but theres some switch on the CB (on mine .. cobra nightwatch thats it)... that eliminates engine noise pickup...

SWR meters are for tuning your antenna so the bandwith is tuned to the CB. Usually tune it so its equal above and below chan 19 but some truckers center it on their preferred or most used channels.

and like i said im to damn tired to remember what SWR metering range is optimal... I remember something like below 2 at chan 1 and 39 is good. .. Its mostly to save the CB from frying when you transmit a signal. You can hurt them if you try to transmit with an antenna thats totally not tuned (to long or to short).....

Firestik antennas have the adjustable screw at the top... HIGHLY RECCOMENDED over the "snip the wire" types.

 

Google search: "ground loop" - some noise is normal. You can go to an inline filter after you confirm that your ground is good.