Cb alternator noise

[sonoma]

from what you are saying is the noise is coming in through the power wires. you can also try a electro cap on the power wires inside the radio to help see if that will help kill some of the noise. try a 1000uf and see if it helps any. put it across the power plug inside the radio. pos to pos and neg to neg. also a inline filter might help you if the cap does not.

[smoke blower]

Ok I can try that and are you talking about the filter that goes inline with the power cord

[sonoma]

the inline filter will only help if the noise is coming in from the power cable. try the cap 1st and see if it helps. if it does you can try a different uf. 470 etc to see if one helps. also where do you have the power wires hooked to. if you just have it hooked to the fuse block can cause a problem. the ground wire should be as close to the radio as possible. some will use the seat bolt to ground a radio. different things work for different people. there is no one quick cure to the problem you have. just like some said the plug wires can cause a problem if they are bad.

[smoke blower]

It is wired to the battery and I tried to ground it to the bolt under the seat no change. I had another 2004 Chevy Silverado and had no issues I don't know why this one is being a pain but my Luck the last 2 months has been unbelievable bad I am about at my end of my rope man its one bad thing after another.

[Scipio Kid]

I forgot to mention, I had a Ford F250 with a similar problem but I didn't have to troubleshoot as much since it was a diesel ... no ignition. The alternator worked fine, charged the batteries fine etc. but the noise was exactly as yours, higher pitched and louder with engine RPM's. The alternator had a bearing start screaming so I replaced it and the whine went with the old alternator. Haven't fixed the Jeep yet, maybe next week and I'll let you know if it quiets down with a new alternator.

[sonoma]

Craig if you do not have good resister spark plugs and resister plug wires you can pick up noise as you have also.. the plug wires will have a marking on them as a resister noise suppresent wire and the plugs will have a R on them with the part number if you want to verify the wires and plugs are the right ones. some people will install non resister items because they are cheaper to buy.

[MDYoungblood]

Ford also had a problem with the electronic fuel injection system making noise but that is another topic. Electronic fuel pumps only run at one speed so the noise wouldn't increase. Since the noise increases with RPM then it is the charging system, sounds like you done as much as you could to find the problem, might be time to seek some other help, find (call around) a audio shop (car sound systems, etc., hate to say it but even Best Buys) they should have equipment to locate the offending noise maker. And yes the radio will transmit a offending signal.
Question, are you checking all this with nothing inline, just the radio? Are all the accessories in the vehicle off, fan motor especially?

3's

Greg

[MDYoungblood]

Spark plug problems make a static crackling sound, even if it is bad injectors it makes the same sound, a whining sound is charging or electrical, something with rotor/stator assembly.

3's

Greg

[Dgrimone]

did you try fair rite blockers on the power leads one on the hot and one on the ground you mite want to try one on the antenna cable as well hope that works

[sonoma]

all he has to do to rule out the alt noise is just pull the belt off to see if he still has the noise or even unplug it. no need to change the alt out to rule it out as the problem. not being there to hear it and see what he has it is all just a shot in the dark.

[smoke blower]

Yes I have ferrite on the positive and negative at the battery and at the back of the radio also have one on the coax . I will try to unplug the alternator tomorrow and see what happens

[Scipio Kid]

If unplugging it doesn't work and if you have the time, pull the belt off too and see if that does it. The alternator is still spinning and trying to put out even when it's unplugged. I'm going to try it on my Jeep too and see what happens. yes, all shots in the dark but good info for all of us. And ... who here doesn't enjoy blasting away in the dark from time to time?

[sonoma]

here is a site with good info on grounding and power leads to help with problems.

[Please login or register to view this link]

[MDYoungblood]

Unhooking the regulator connector should kill the noise. Not a good idea to remove the belt on an aluminum engine block, a couple of minutes running without water flowing around the cylinders can cause warpage.

3's

Greg

[smoke blower]

Well I put in a galaxy94 HP and now the noise is almost gone so I can deal with that I don't think it is going to be any better

[Bluerunner]

I run my power through RG8 coax. One piece is good enough for powering a radio. +12vdc on the center and - 12vdc ground on the shield. It becomes a very long linear capacitor that has low inductance to noise .

[sonoma]

glad that putting in some thing other than a cobra 25 helped with your noise issue. that was why earlier in the post I asked if you had tried another radio. over the years I have never had good luck with a cobra 25 as far as noise issues. even the other cheap cobras I have had noise issues. most truck drivers here in Oklahoma do not like the cobra 25 radios. about the only truck driver radio here is a cobra 29 as far as a straight AM radio. then they want echo and a A+ kit installed for channels. even a superstar 121 radio is hard to sell to a driver because they claim the radio is not as quiet as a cobra 29. the 121 has upper and lower channels but they do not want one. it is hard to get 50.00 from a truck driver here for a 121. they will pay good money for a 29 LTD radio with upper and lower channels. heck they will pay 100.00 for a new cobra 29 then spend another 100.00 plus for channels and echo.. as long as they have channels will make them happy. at the shop my buddy can get 125.00 plus for a used cobra 29 with channels. I buy up all the A+ kits I can find for him. the drivers do not want a plain A kit for channels since it is not inline with other radios on the lower channels. in fact all they want is lowers here with the regular 40 channels. the guys run lower 19 here most of the time on local drivers such as rock haulers. they like 26.735 for local running.

[smoke blower]

Thanks for all the help and Sonoma I did try a few different radios I tried another cobra 25 , cobra 29 , and a Galaxy 66 and still had the noise so I decided to try one last radio which was the Galaxy 94 hp and that worked it's the only radio that stopped the noise.And thanks also Bluerunner for the info that might so.help stop alot of noise.

[Scipio Kid]

Well, once again, Galaxy saves the day! I'd like to try that coax thing on the power supply. It seems to me it could be a problem with a bigger (higher wattage) radio. You see some of these guys running a #12 or even #10 supply wire for those. Never measured the size of the tip wire in the RG8 bit it seems to be about a #16 or even a #18. Watts gotta have wire. But a great idea worth trying out.

Also, sonoma, I've got several (6 or 7) extra Cobra 29's if you or your buddy are interested, and I can get my hands on another 10 maybe (a local guy who's selling a bunch). I almost bought them for a good price because there was no shipping involved (but he didn't have mics for any of them ... who has 10 radios with no mics? That's just weird.) It's often the shipping that's a problem. You find a good radio for 40 bucks but they need another 40 to ship it. A good deal at 40 isn't so good at 80. 40 bucks in mods makes a radio better, 40 in shipping just makes it cost more, dang. (No offense if any of you are UPS or USPS drivers.)

-- Sunday, 23 October 2016, 7:16 AM --

Oh, also, now that we've basically trashed the cobra 25 on the noise issue, I've got 3 I'll sell cheap!

[smoke blower]

Nothing wrong with the cobra 25 I love that Radio and I have run them in every truck I have had and never had an issue but this is the first truck I ever had any issues with. I would love for the one I have to work in the truck it's smaller and don't take up much room but unfortunately it would not work.