Jeep Wrangler Forum banner

1 - 20 of 21 Posts

·
Registered
Joined
·
1,616 Posts
Discussion Starter #1
So I have some interference coming through my CB antenna.

When my antenna is disconnected from the CB there's no interference except for a little from my A-pillar LED lights. When the antenna is plugged in you can hear motor interference and my lights make much worse noise.

The CB is wired direct to the battery. Lights are also wired direct to the battery through relays. My antenna should be well grounded. I have an aluminum antenna mount attached to bare metal on my rear quarter pannel. I have a Firestick antenna as well as the FireRing cable.

Any suggestions on what I should try? Maybe a new cable to see if that fixes anything...?
 

·
Premium Member
Joined
·
368 Posts
Double check that you have a good ground.
 

·
Super Moderator
Joined
·
9,595 Posts
So I have some interference coming through my CB antenna. When my antenna is disconnected from the CB there's no interference except for a little from my A-pillar LED lights. When the antenna is plugged in you can hear motor interference and my lights make much worse noise. The CB is wired direct to the battery. Lights are also wired direct to the battery through relays. My antenna should be well grounded. I have an aluminum antenna mount attached to bare metal on my rear quarter pannel. I have a Firestick antenna as well as the FireRing cable. Any suggestions on what I should try? Maybe a new cable to see if that fixes anything...?

I tried a Firering on my Tow rig and I couldn't get the SWR to anything close to good. I switched to a regular cable and mount and perfect but still had diesel noise. I added a grounding strap and everything cleared up. I would try a grounding strap. Have you tuned the antenna's SWR yet?
 

·
Registered
Joined
·
348 Posts
Not uncommon to have ignition/accessory noise feeding into a radio. AM is worse than FM and that is what a CB is ( AM ).

Proper grounding of the antenna mount is critical. Some antennas are worse than others. Cable isn't likely going to make much difference as long as it is in good shape.

Typically this noise comes from the power leads. You can buy "chokes" to install on the power leads or build your own. Do an online search. This is likely to net the best results......
 

·
Registered
Joined
·
1,616 Posts
Discussion Starter #5
I tried a Firering on my Tow rig and I couldn't get the SWR to anything close to good. I switched to a regular cable and mount and perfect but still had diesel noise. I added a grounding strap and everything cleared up. I would try a grounding strap. Have you tuned the antenna's SWR yet?
I have tuned the antenna down to a decent SWR (it's been a while so I can't remember specifics but I do remember it being decent but a little high). How exactly would I add a ground strap? Where would I ground it to? My mount is on the upper part of my passenger rear quarter panel. The screws come through the body right next to where the back corner of the roll cage attaches to the tub.
 

·
Super Moderator
Joined
·
9,595 Posts
I have tuned the antenna down to a decent SWR (it's been a while so I can't remember specifics but I do remember it being decent but a little high). How exactly would I add a ground strap? Where would I ground it to? My mount is on the upper part of my passenger rear quarter panel. The screws come through the body right next to where the back corner of the roll cage attaches to the tub.
You'd run the strap from the mount to the frame.
 

·
Registered
Joined
·
1,616 Posts
Discussion Starter #7
You'd run the strap from the mount to the frame.
I'd have to figure out how to do that from inside the Jeep. Could I run that to other bolts inside the Jeep or it has to go to the frame?
 

·
Registered
Joined
·
348 Posts
It does not have to go to the frame. The body tub is grounded with a braided strap to the frame also. You can run a braided ( braided is many times better than regular wire ) strap from your mount to a really good location on the body. This will only help enough to matter if your current mount is not grounding properly. Which means there is paint or something interfering with the connection of the antenna mount to the body.
 

·
Registered
Joined
·
1,616 Posts
Discussion Starter #9
It does not have to go to the frame. The body tub is grounded with a braided strap to the frame also. You can run a braided ( braided is many times better than regular wire ) strap from your mount to a really good location on the body. This will only help enough to matter if your current mount is not grounding properly. Which means there is paint or something interfering with the connection of the antenna mount to the body.
That is what's confusing me... I ground the paint off the body so my whole entire mount is contacting bare metal on the body of the Jeep. This should be the best possible ground it could have which is why I am confused about what else could be causing me these issues.
 

·
Registered
Joined
·
348 Posts
If you were careful to grind/remove the paint for the antenna base/mount then your ground is probably as good as it needs to be.

As for what else is the problem, I am pretty sure what I mentioned earlier will be what fixes the problem. I suspect you are getting power conductor feedback. Meaning signals are coming in through your positive and negative power leads. You mentioned you were connected to the battery, which is the best way to do that for sensitive radios. Are both the positive and negative leads hooked to the battery? Next you could look at routing. Are your leads near any electronic modules under the hood or dash? Beyond that, installing chokes in the power wires is your likely answer. You can test this by running power from a remote battery and hooking close to the radio with other leads disconnected from the radio and see if the noises go away.

Here is an example: Choke
 

·
Registered
Joined
·
1,616 Posts
Discussion Starter #11
If you were careful to grind/remove the paint for the antenna base/mount then your ground is probably as good as it needs to be.

As for what else is the problem, I am pretty sure what I mentioned earlier will be what fixes the problem. I suspect you are getting power conductor feedback. Meaning signals are coming in through your positive and negative power leads. You mentioned you were connected to the battery, which is the best way to do that for sensitive radios. Are both the positive and negative leads hooked to the battery? Next you could look at routing. Are your leads near any electronic modules under the hood or dash? Beyond that, installing chokes in the power wires is your likely answer. You can test this by running power from a remote battery and hooking close to the radio with other leads disconnected from the radio and see if the noises go away.

Here is an example: Choke
The reason that I do not think this is the case is that when the antenna is unplugged there is no noise except for a very little bit when I use my A-pillar lights. When the antenna is connected I have motor noise as well as light noise that peaks my CB. If the noise was entering through the power leads then I should have the noises even when the antenna is disconnected, no?
 

·
Registered
Joined
·
348 Posts
Well, I have given my advice.

You might say I have some credentials to cover what I wrote.

Your coax has a braided shield the entire length of it under the plastic cover. Unless there is a break in that it is very difficult for stray signal to get into the coax and into the radio. There can be interference issues with the coax next to a source of interference, but that is usually less of an issue than the power leads.

Grounding is often not a noise issue but instead a standing wave issue. As long as your standing wave measurement is under 2:1 it will work. Lower is better, but not all that much for this purpose. It has nothing to do with noise.
 

·
Registered
Joined
·
1,616 Posts
Discussion Starter #13
I will definitely try your advice. I honestly can't imagine the antenna being the problem because of the work I did to ground it to the body... I just don't know anymore... My SWR is about 1.4 on channel 20. I am not sure about the ground for the radio but if memory serves me right it is grounded somewhere near the pedals. What kind of remote battery source could I use to test this? Would something like a 9v battery work or would I need to figure out some way of getting a lot of power?
 

·
Knows a couple things...
Joined
·
48,957 Posts
This is a question that may seem too obvious but I never know the background of people where it comes to radios & electronics....

When you get the noise from your lights, is your Squelch turned up sufficient to quiet the radio's normal hiss? And when you turn the lights on that noise is there even with the Squelch adjusted up enough that it would normally quiet the hiss?

One more question... are you running the recommended spark plugs or could someone have installed non-resistor spark plugs in hopes of better engine performance? The spark plugs are supposed to be resistor type to eliminate spark noise, their use will not reduce engine performance.
 

·
Registered
Joined
·
1,616 Posts
Discussion Starter #15
This is a question that may seem too obvious but I never know the background of people where it comes to radios & electronics....

When you get the noise from your lights, is your Squelch turned up sufficient to quiet the radio's normal hiss? And when you turn the lights on that noise is there even with the Squelch adjusted up enough that it would normally quiet the hiss?

One more question... are you running the recommended spark plugs or could someone have installed non-resistor spark plugs in hopes of better engine performance? The spark plugs are supposed to be resistor type to eliminate spark noise, their use will not reduce engine performance.
The lights when turned on will peak my radio up to the red. I'd have to have my squelch all the way up if that would even quiet it.

I'm running Champion iridium 9034 plugs. I wasn't hoping for better engine performance and I saw on the forum that these were a good replacement.
 

·
Registered
Joined
·
348 Posts
I am not sure about the ground for the radio but if memory serves me right it is grounded somewhere near the pedals.

What kind of remote battery source could I use to test this?

BOTH power leads ( ground and positive ) need to run directly to the battery for best performance. If grounded to the body metal, stray signals can get to it easier.

Has to be 12 volts. It would take very little power to listen to the CB. A small motorcycle, lawn mower type battery would work fine if you have one.

If you want to work on it without spending money, I would make sure both the ground and positive wires connect directly to the battery with no other connections inline with them.
 

·
Premium Member
Joined
·
555 Posts
aluminum is not the best conductor. try a short jumper wire from the antenna ground to the mounting bolts that hold the mount to the body. use ring connectors, and keps washers or lock washers with internal/external teeth. it will help. does the static vary with engine speed? radio shack, a cb store, a good car stereo store, or even a truckers store should be able to provide you with a "kit" to clean your power up, as mentioned above.
you could always break out the o'scope and see exactly what the "noise" is, and design yer own filter.......
 

·
Knows a couple things...
Joined
·
48,957 Posts
aluminum is not the best conductor
Aluminum is not be the best conductor but it's in the top four... silver, copper, gold, aluminum in that order. For the short lengths of connections aluminum mounts are used for, they are fine... especially in light of their thickness and large surface area when compared to wiring.
 

·
Registered
Joined
·
233 Posts
T.Wagner did you ever figure out what the problem was?
 

·
Registered
Joined
·
1,616 Posts
Discussion Starter #20
Not really... I still have interference but I wired the ground direct to the battery and it cleaned it up a little more. It's good enough for me at this point.
 
1 - 20 of 21 Posts
Top