Ground

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

nicksfj-40

nicksfj-40

10 Year 15 Year
Joined
Apr 11, 2006
Threads
49
Messages
304
Location
Tulsa, Oklahoma
Where is the best place to ground a CB. I am running a noise filter and have the CB wire directly to the battery and grounded to the firewall. The filter really cut down on the motor noise. I guess it was alternator whine. The battery is grounded to the frame, then to the block, then to the firewall. I am still getting electrical nise and when I turn on the wipers or the heater that is all that I can hear. Would it be better to ground it to the roll bar since that is where it is mounted? Thanks.
Nick
 
Last edited:
Nicksfj-40;

Keep in mind that an old (or new) FJ-40 will have a lot of RFI induced into a non-FM style radio system.

Inter-grounding of FJ panels, axles, fenders, fire-wall & Frame does help, but does not always help.

Filters, such as these:

http://www.powerwerx.com/search.asp?Action=search&Keywords=filter

will help; but, they help on the low voltage side, not the RFI side, spark plug side, which generates goobs of noise.

That does'nt help much does it?

I've been messing with this for years on my FJ-40 and have not solved much; except using FM on VHF/UHF systems.

As far as grounding ur CB goes, do this:
Use 1/2 inch tinned strap (not a piece of wire) from the Radio to the roll bar. Use 1/2 inch tinned strap from the roll bar to the FJ-40 body. Use 1/2 inch tinned strap from the body (fire-wall) to the engine block and then to the neg battery terminal or cruiser frame. Be sure grind off paint; metal-to-metal contact.

the reason for strap vs wire is that strap is a low impedance to RFI noise while wire (say, #10) is/will act like an antenna to noise and radiate same into ur radio. The 12v input should be thru a filter and as close to the radio as physically possible.

This subject can be very complicated and studying same will create mind problems - beware.

...
 
You are getting noise from the engine and electrical accessories, but can't you squelch it out and still get good radio performance? I think no matter how well you filter your power, you will still have engine noise at the lowest squelch setting. Is the interference you are getting so strong that you can't silence it with squelch?
 
Thats affirm. I get so loud you would have to be sitting in my lap for me to be able to receive past the squelch. I will try the ground thing with the metal strips. I have my CB mounted on my rollbar and the filter under the dash. I dont really wnat that thing up on the roll bar. My girlfriend is already saying the mic cord is in her way. (like she needs to be able to see). Anyways thanks for the help. Where can I get the metal strip stuff?
 
nicksfj-40 said:
Thats affirm. I get so loud you would have to be sitting in my lap for me to be able to receive past the squelch. I will try the ground thing with the metal strips. I have my CB mounted on my rollbar and the filter under the dash. I dont really wnat that thing up on the roll bar. My girlfriend is already saying the mic cord is in her way. (like she needs to be able to see). Anyways thanks for the help. Where can I get the metal strip stuff?
Click to expand...

nicksfj-40 said:
Anybody? Bueller?
Click to expand...

Move the filter.

The metal strip stuff is called ground strap, look for it at auto parts stores or radio supply places.

I'd save your money until after you get the filter as close as possiable to the radio power connections. If you still have a problem then add ground wires or straps to the roll cage/body.
 
Can you get clean power from a location in the cab? Having a long run from the battery to the unit is not ideal. If you look around you can find twisted pair wire that will help cut RF noise and you can actually get shielded twisted pair. Also keeping the ground wire as sort as possible coming from the unit will help, that decreased the noise I had in my unit.
 
If the interference is coming from the heater or wiper motors, then one solution would be to not use them. Sure, you'll be cold and not able to see where you're going, but hey, the radio will work well! :D

Another solution in addition to the grounding previously mentioned, would be to put a .01uf capacitor on the power leads of each of the motors, as close to the motor as possible. Also check for any corrosion where the motors are mounted. Use a high quality coax for the antenna (no radio shack crap) and mount the antenna at the rear of the vehicle if possible.
 
You must log in or register to reply here.

Share this page

Back
Top Bottom