straxcla

I installed my CB radio and antenna, my SWR ratings are acceptable and the antenna is well grounded. I have a hot wire directly to the battery and a ground on the chassis. But the engine noise interference is so bad I can't really use the CB when I'm driving (which slightly defeats the purpose...). The engine noise is still there when I unplug the antenna so I'm 99% sure it's coming from the power line. Also my radio is really old so I don't think it has a noise filter built into it. Have any of you used power line filters to solve a similar problem, and which ones are actually work? Any other solutions to this problem?

Fred/N0AZZ

You need to run the ground wire direct to the battery also it will act as a filter for you, unless you have other issues. All of my radios are ran this way in 4 of my cars and Jeeps they are Amateur radios in them. None of my radios require any external filtering of any kind. Once you have the ground properly installed I think you should be fine.


The XJ has a CB along with the others only because its required by some clubs on their rides to have one. On both of these radios all you can see is the control head or for the CB a Cobra all in one Mic/Spk/Vol/Tun/Sql main units mounted under pass seat on a slide out tray.

chpalmer

Absolutely not! Speaking as a 30+ year experience radio tech here.

Running the ground direct to the battery can in fact cause more noise because the longer ground acts as an antenna and picks up noise. There are no radios which explicitly filter the ground side of a radio.

Can also act to carry current through the antenna ground through the radio and to the ground side of the battery especially when the primary ground strap has higher resistance for whatever reason. This can eventually destroy the radio.

Don't use black screws to make the ground connection to the body. They will eventually cause issues. Don't coil extra wire or antenna coax. Make figure 8s or cut to length. Keep the ground lead short and sweet.

Give your Jeep a good tuneup and use the proper wires and plugs.

You may need to move the antenna away from front of the vehicle.

Talk to your local auto parts store about RFI suppression for your ignition if all else fails. If your heater fan is noisy you can install a capacitor that will help quiet it down. If it's alternator wine then you may have a bad diode in the alternator, or in the case of a radio that has no line protection use a line filter on the power lead.

straxcla

My antenna cannot get any further away from my engine, it's on the back of the Jeep. Plus the problem persists even when the antenna is disconnected. Any line filters that you recommend/have experience with in particular?

chpalmer

I missed the part where you said you still hear it with the antenna disconnected.

We use these- https://www.google.com/?gws_rd=ssl#q=laird+NS1535

Id be more inclined to want to find out whats generating the noise in the first place.

Is it a high pitched whine that follows the engine? Or does it sound like ignition noise?

straxcla

It's sort of like a static that gets louder and faster and turns into a whine when I rev the engine.

Fred/N0AZZ

BS I'm an Amateur Extra Class and have dealt with many radio installs CB's going back to the early 70's and in the last 10 yrs have built several HF Radio's. Any fool knows the battery is the best filter when it comes to noise in the system!


What kind of a radio tech do you claim to be anyway not a communications one for sure.

chpalmer

Amateur extra class means you probably know your Moris code eh?

I do law enforcement and commercial. I have over 1000 installs under my belt. I design and build systems. And yes Im licensed. I was kinda serious about that 30 years in the industry comment.

You have no clue what kind of shape his electrical system is in to be recommending a secondary ground path to the battery. Yes the battery is a terrific filter but you are most likely inducing other issues.

Filtering is a band-aid. Fix the cause and you will be better off. Running a ground right next to the noise source is just not smart. Providing a secondary ground path to the battery through radio equipment isn't much smarter. Hope you have fuses on your ground leads!

Fred/N0AZZ

Yes I do know code but seldom use it any more mostly "Digital" now. As far as LE install's I did those for a small department for about 6 yrs including the emergency lighting install.


I have reprogrammed quite a few of the old 110w 6m VHF radios from the MO.HP when they changed to a new system. I set them up for amateur use on those bands.


You might learn to read better as I stated in the first sentence that most likely take care of the problem unless "He has other issues"!


As far as grounds it is NOT a secondary ground it is the primary one with a direct connection to the battery, not as you suggest through the body where everything in the system is grounded also.


Its a good thing all your hooking up is commercial radios as they are much more forgiving than others. I do use fuse's on both lines BTW of the proper rating. Also as I said he might have to add a filter if he still problems or correct them being an Alt., Plug wires etc.


I'll let you handle all the installs for people then you can tell them what's wrong when they don't work properly.

chpalmer

You can lead a horse to water...

Fred- I read just fine. Yea for the radio it is the primary ground but it can become a secondary ground for the rest of the vehicle. Don't believe me? Disconnect your negative cable from the body and engine block and turn something on.

My installs have to last 10 years + because that is policy. I have no call backs. Those who do too many in our shop find other jobs.

But I understand that your a ham and in in your blood to argue.



straxcla- Try whatever and report back. Good luck!

salad

Freshening the grounds is a good idea.

One very important thing I haven't seen mentioned yet:

How old are your spark plug wires?

Fred/N0AZZ

Here you made my point about the battery being the best filter, you should have just stopped there.


I also teach and do testing for the FCC for all class's of license's and can tell you only a small percentage of those who are licensed ever try pass the extra exam. Of those who do only about 28% are successful. Where most all fail are in advanced communications electronics, electronics theory, advanced math, printed circuits with components installed naming all parts installed and values, drawing 3 circuits of a named item questions.


You should attempt to try and pass a sample test online there are over 5000 possible questions in the question pool, only 50 on the test. If you read the ARRL manuals for all 3 class's you will have all the answers to pass.


My license gives me the right to design, build and operate it on the airways without FCC approval, I know and adhere to the rules of design. In fact have 3 in front of me now. Can you do that with your license?


Just do it right the first time then look for other issues and fix those, this one is free.

straxcla

They are actually fairly new, maybe a year old? I ordered the cap, rotor, and plug wires from summit racing. Spark plugs are even newer still and i did gap them correctly when I put them in. I ordered a $10 power line filter so I will see if that works. If it doesn't maybe find a better ground? What other engine issues will come through as static on my radio?

Fred/N0AZZ

The alt. is another one that might be it.


On my 04 WJ for an HF radio I ended up having to ground the hood to the frame along with fenders then the 4 doors and cargo door also to get rid of all my static plus the exhaust system to the frame. These were not all my ideas, but one's that have proven by the FCC to work.


Some cars are harder to find all the problems on than others, the direct battery ground takes care of most, but not all, all of the time.

chpalmer

I'm completely familiar with what an amateur license allows and does not allow. You seem to believe I'm not an amateur operator... Having the license on paper is good in all but doing the work correctly is the real test.

I brought this up to a retired Motorola engineer yesterday. He pointed out to me that there is an article in QRZ that talks about this very subject. Shows the danger of passing up the vehicles single point ground system especially in newer cars.

We used to install lightbars in cars that drew just under 50 amps when operational and we still never bypassed the vehicle single point ground to do so. We instead might add an extra ground between the battery and body per our engineer's instruction. Of course everything we do now consists of LEDs but the 110 watt radios still get installed.

Since my continued education actually comes from the manufacturers...

Anyways- ground systems I design these days need to survive lightning strikes and so far have.

Fred- Good luck! Hopefully you never burn up any of your equipment with your install methods, or the equipment of anyone else by your advice.