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Another thread about CB static and whining


qslim

Try putting a torch on it
Supporting Member
Joined
Sep 17, 2018
Messages
407
Location
Utah
Over the past week I installed a Uniden 520xl and mounted a Firestik antenna with a spring mount on the teraflex taillight fixture at the rear left. The radio is powered straight from the positive terminal and grounded to the tub in the driver wheel well. Ran my 18' of cable, did a nice figure 8 with the slack as instructed. Tuned it with an SWR in the middle of an 40 acre alfalfa field, I'm dead at 1 on 40 and about 1.2 on 1.

Reception seems nominal, I got good radio checks perched on a hill above two highways near a truckstop, but only with the Jeep turned off. When I turn the key to the on position and start the engine an overwhelming whine takes over, I have to turn the squelch about another 45 degrees to the right to get rid of it, and any transmissions I receive are masked by whine and static. It should be noted that the whine is not related to engine speed. There is a very slight background noise that correlates to RPM but it is very subtle.

I thought I might have a grounding issue, so I removed the third bolt on the tail light mount (the one you have to drill to tub for) and took some paint off around the hole down to bare metal, then I did the same thing on the tub side for the nut. I added some washers on both sides to ensure a solid ground from the mount to the tub and verified about .8 ohms to ground.

I also checked for ground isolation on the antenna side of the mount. At first I was reading 2.2k ohm to ground which seemed odd, but I forgot to disconnect the cable (is that a normal reading to ground shooting into the radio? I have no idea...). With the cable disconnected the antenna side of the mount is open to ground. I also disconnected the cable from the back of the radio unit to check the cable itself, and the inner/outer conductors are isolated from one another like they should be.

Any ideas how I can get rid of this terrible whine and static?
 

Indy

TJ Enthusiast
Supporting Member
Joined
Apr 15, 2019
Messages
138
Location
Roseville CA
Try your ground directly from the battery.

Sent from my Pixel 2 XL using Tapatalk
 
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Mr. Bills

TJ Addict
Joined
Nov 24, 2017
Messages
1,896
Location
Area Code 530
If your power lead crosses the firewall from the battery side to the driver side you are probably picking up ignition or other electrical "noise." The injectors are likely culprits.

Some people have tried re-routing the power lead from the battery through the firewall behind the glove box rather than on the driver's side and shielding the power lead as it crossed the firewall with braided copper tubing and then grounding one end of the shield. I fussed with minimizing noise using these techniques and others but in the end I decided that using the ANL feature on the Uniden Pro520XL worked just as well.
 

TurboTJ

TJ Enthusiast
Supporting Member
Joined
Jan 5, 2019
Messages
248
Location
Walnut Creek, CA
If when you turn the ignition on but don't start the engine and you get a few second burst of noise that then goes away, it is probably coming from the fuel pump. The pump turns off after developing pressure. With the engine running it is on continuously.
 
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OP
qslim

qslim

Try putting a torch on it
Supporting Member
Joined
Sep 17, 2018
Messages
407
Location
Utah
I routed my power from the battery directly down behind the glovebox, so it isn't crossing over the engine. Good to know though, I didn't even consider injectors when running it.

@Indy I think you might be on the right track w/ the radio ground... I didn't have time today to run it to the battery but I did find a cleaner looking chassis ground point in the footwell. My dumbass tried to pickup a ground off a self tapping screw going through a plastic tab, so I was grounding through a 20 year old rusty screw. Dunno what I was thinking. Anyway after getting on a proper chassis ground the reception improved, still have some static & whine but it is tolerable and much better.

Static & Wine sounds like a bitching callsign.

Thanks all for the input!
 
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tworley

TJ Addict
Supporting Member
Ride of the Month Winner
Joined
May 23, 2018
Messages
2,792
Location
Morrison, CO
Ive wired mine directly to the battery (POS & NEG). No whine at all!
 

Crusty

New Member
Joined
Apr 26, 2019
Messages
3
Location
Keansburg
Over the past week I installed a Uniden 520xl and mounted a Firestik antenna with a spring mount on the teraflex taillight fixture at the rear left. The radio is powered straight from the positive terminal and grounded to the tub in the driver wheel well. Ran my 18' of cable, did a nice figure 8 with the slack as instructed. Tuned it with an SWR in the middle of an 40 acre alfalfa field, I'm dead at 1 on 40 and about 1.2 on 1.

Reception seems nominal, I got good radio checks perched on a hill above two highways near a truckstop, but only with the Jeep turned off. When I turn the key to the on position and start the engine an overwhelming whine takes over, I have to turn the squelch about another 45 degrees to the right to get rid of it, and any transmissions I receive are masked by whine and static. It should be noted that the whine is not related to engine speed. There is a very slight background noise that correlates to RPM but it is very subtle.

I thought I might have a grounding issue, so I removed the third bolt on the tail light mount (the one you have to drill to tub for) and took some paint off around the hole down to bare metal, then I did the same thing on the tub side for the nut. I added some washers on both sides to ensure a solid ground from the mount to the tub and verified about .8 ohms to ground.

I also checked for ground isolation on the antenna side of the mount. At first I was reading 2.2k ohm to ground which seemed odd, but I forgot to disconnect the cable (is that a normal reading to ground shooting into the radio? I have no idea...). With the cable disconnected the antenna side of the mount is open to ground. I also disconnected the cable from the back of the radio unit to check the cable itself, and the inner/outer conductors are isolated from one another like they should be.

Any ideas how I can get rid of this terrible whine and static?
Look online for a Radio Shack noise filter it's one of the best made
 

ac_

zombicon
Supporting Member
Joined
Jun 15, 2017
Messages
4,340
Location
AZ, United States
I have wired up some interior red lights in my Jeep. I call them my "zombie" lights. Anyway I grounded my CB the same place I grounded those light so when have my cb light and my zombie lights on it whines. I can squelch it out, but it is pretty loud if I don't. I am going to fix it sometime, but for now I am sharing with you in case you are sharing a common ground or a strip if common grounds it is possible that is your culprit. like others said grounding to your battery should fix you up. If not find a good ground that is off on its own and the might work too.

Oh and since we are going to meet tomorrow or Sunday I can show you first hand.
 

prerunner1982

New Member
Joined
May 13, 2019
Messages
1
Location
Oklahoma
I have wired up some interior red lights in my Jeep. I call them my "zombie" lights. Anyway I grounded my CB the same place I grounded those light so when have my cb light and my zombie lights on it whines. I can squelch it out, but it is pretty loud if I don't. I am going to fix it sometime, but for now I am sharing with you in case you are sharing a common ground or a strip if common grounds it is possible that is your culprit. like others said grounding to your battery should fix you up. If not find a good ground that is off on its own and the might work too.
I am going to guess that these "zombie" lights are LEDs?
Your problem is more likely the LED and not the shared ground.
LEDs work off a switching power supply and it is common for them to be quite noisy.