Testing a CB Antenna Ground with a Multimeter

How to Ground a CB Antenna:
Perhaps you’re doing an original installation and want to know how to ground a CB antenna. Perhaps you’ve already installed it, tested your Standing Wave Ratio (SWR), found it too high and want to improve your CB antenna grounding. Or, perhaps you’ve noticed that you’re not getting the CB radio performance that you should be. In any case, the first step is to test your CB antenna’s grounding.

Testing the CB Antenna Ground:
You’ll need a multi-meter to check your CB antenna's ground. If you need to know how to use one, read our article on Testing for Continuity. An easy way to test your antenna's ground is check continuity between the CB antenna mount and your vehicle ground, because if the antenna mount is well grounded, so is your antenna.

To test for continuity of electrical signal, you will need to touch the probes for your multi-meter in two locations. You can use either the red or the black probe to touch either location. The following provides step-by-step guidance for testing the CB antenna ground.

Step-by-Step Instructions: Grounding a CB Antenna:
Touch the first probe to the CB antenna mount in order to test the CB antenna ground

Where to Put the First Probe
Lay the first probe where it touches your CB antenna mount. Lay the probe flat across the mount surface, being careful not to touch the vehicle with the probe.

Where to put the 2nd probe when testing the antenna ground
Be cautious working around your battery as you complete this step. The second probe should touch the negative terminal on your vehicle's battery (marked with a minus sign). Take care not to touch the positive terminal (the one marked with a plus sign).

Alternative location for placing the 2nd probe when testing cb antenna ground
If it’s not possible to reach both the CB antenna mount and the negative terminal of the battery with the probes, find a good ground on the vehicle (such as the one pictured) and use that for the second probe's contact point.

Interpreting the Results of the Continuity Test
If your CB antenna mount has a good ground, the multimeter needle should move all the way to the right when the probes contact these two locations. If you get very little or no needle movement on the multimeter, test that your meter is working properly by touching the two probes together. If the needle moves all the way to the right, the meter is working properly. So, if the multimeter is functioning and you’re getting little or no needle movement, you’ll need to try to improve your CB antenna grounding. Good grounding establishes a ground plane for the system.

How to Ground a CB Antenna Mount
If your antenna mount is one that is designed to accept a coaxial plug (such as the 2 ended PL259) or a PL259 with a fire ring on the other end (such as the FireStik MU8R Single Antenna CB Coax) then your work is easy. Just make sure that the mount is attached to the frame of your car or truck securely, and you should be good to go. If for some reason you need to correctly attach an end to the coax cable (perhaps you're making your own), this reference has pictures step by step for attaching both screw-on and crimp style connectors to a coax cable. Here is a technical reference for what’s inside the coaxial cable with a picture of what you’ll encounter if you strip it back.

What kind of strapping hardware do I need?
If your antenna doesn’t accept a coaxial plug then you’ll need to provide a ground another way. Although some CB owners use 10-gauge wire for a ground, braided ground strapping is preferable. That’s because of reactance. Reactance can change the wire into an antenna rather than a radio frequency (RF) ground, which is the opposite of what you’re trying to accomplish.

Where to Ground a CB Antenna
When you’re deciding how to ground your CB antenna system, recall that the antenna will be more efficient when you use the most metal on your car. To pull the metal together, you may need to bond the metal parts by using more than one ground strap in different locations. That will also provide insurance against the accidental floating of the negative power lead. You don’t want to run a strap all the way from the mount to the battery for the same reason.

Worth mentioning again is that the most important part of getting a good ground is to attach the ground to metal rather than plastic or other materials.

To get a better ground, you could move the mount and the antenna to a different location with a better ground. Or, you could add an additional grounding strap to the mount. If you aren’t concerned about appearances on your vehicle where your antenna is mounted, you could (gasp) scrape the paint off underneath the mount to have a metal-to-metal ground, but would be the least desirable option to most of us.

[johnfrint]

1. Does CB unit need to be on.
2. If so, any particular settings need to be set on it before/during/after test procedure?
3. What does/should multimeter be set to e.g. ohms, dc current, ac/dc volt, continuity.?

[wearecb]

1.No, when you are testing a ground, you don't need to turn anything on.

2.N/A

3. In this video we have it set on ohms. We are testing continuity, though, so if your meter has a setting that says "continuity" that might be a good way to go as well.

[johnfrint]

timely-reply! quick! easy! simple! to the point! tip my hat to ya' and thank-you.

[dangerdoberman]

I recently put a CB and everything in my 97 Blazer and custom antenna bracket. I sanded the paint and surface clean where ever I needed ground and after everything was secured and tested I painted over everything again to keep corrosion off.

[NAVYABHAN]

As much as it pain's me to do it, "In my Mechanical Heart" I know I must "CHIP THE PAINT ON MY JEWEL!"

[DeathScouter]

You only missed the most important part.... making sure the ANTENNA is grounded, not just the MOUNTING BRACKET. And I'd love to know how you do this test with a test light if you didn't have your multimeter handy.

[MNDashcam]

My antenna has a magnetic base so how exactly should I ground this?

[brianyetzke]

How can I check if my fiber tigar antenna is good with a owm meter

[LoneRedDragon]

I am mounting my antennas in my bed what would be the best way to ground it?

[majordave]

I bought a 102 whip antenna and a coax cable for a 2005 jeep wrangler. The coax cable had a hot wire and ground wire at the antenna end. Both were attached correctly to the antenna mount. However, it did not work. (When I disconnected the ground wire from the mount and held it in my hand it worked. Does the mount itself also have to be grounded to the vehicle somewhere?
Thank you.

[MrJohndeere]

do cb antennas have to be grounded?? & could i use 18GA grounding wire? im going to put a cb on my ATV.

[donmunro]

One important thing you missed is to put the multimeter on the ohm test.

[Bxcowboy]

What brand antenna mount is that and where does the PL-259 connect to the mount. This could be a perfect solution for my needs

[exaotic]

My antenna is mounted to my toolbox, is there a negative ground near there I could use?

[dunnoyolo]

have a antenna and what wire goes to antenna and what one goes to bracket one wire is black and one wire is white ?

[woodybeeyou]

you completely forgot to instruct what the multimeter is to be set for, obvious its ohms, but you thought everybody should know that, sorta like you thought shit was jelly and you had some, thanks for nothing with a big thumbs down

[FoxR]

Hi, I just installed a Lincoln 2+ 18 feet of coax and a Francis 5.5 hot rod the hood fender of my 18 Silverado z71. I’m getting 1.5 ish SWR and am able to talk to others pretty easily. My problem is the amount of RF static I get. It’s always around 4 or 5 lights all the time no matter where I am day or night or what frequency I am on it’s always the same. I also notice when I turn my steering wheel it effects the amount of static I get as well. What the hell did I do wrong lol?

[jaynj]

Tried that found a questionable ground in right antenna still can't transmit

[brianyetzke]

High SWR with the fiber antenna the magnetic mount is great but the fiber is not...

[WereNotEqual]

Can you have ground, but not have a good ground.

Is there a way to test for ground quality?