Whine noise

[Thisdude08]

I am kinda puzzled by this...In the mobile most times it's nice & quiet...no whine or very little.
Sometimes though all of a sudden whine will come in & If I key the mic
it goes back to normal (no whine). I've even had it do it parked where from
out of the blue alternator whine shows up. I have to key the mic to make it go away & then
it might stay away for hours (if I am lucky) or just minutes. The volume of the whine can vary
& can even get loud on occasion when the problem surfaces.

Sometimes on my hour commute home it will only do it once or twice & other times
it seems to do it off & on the entire ride. It does this in any type of weather.

The radio is the Cobra 200 GTL DX & the vehicle is a 2004 F-150 w/Wilson 5000
mag mount. I am beginning to wonder if I have a cold solder joint? The radio is wired to the battery
& I have tried the neg wire to the frame with the same results.

Any ideas? Thanks in advance...

73's !

[ironic]

have you tried changing the mic

[Thisdude08]

Hi Ironic,

Yup...I have...no luck...I'm really thinking it's inside the radio but wishing it was not

[ironic]

sorry maybe someone else will know

[316]

Could be alternator or AC pump noise.

[Shakedown101]

If You can take radio out and put it inside your house on a power supply , Be sure to have mic where nobody can key radio , unless you maybe have a base antenna or dummy load , anyway if radio is out of vehicle and on a different power source and still has the same problem this pinpoints the problem to the radio and not the vehicle in anyway.
Thanks Shakedown101 Lockdown Communications.

[Thisdude08]

I have tried the radio on a power supply but it wouldn't
show alternator whine in the house anyway...seems to be okay otherwise.

It seems that it is indeed alternator noise & lately going over a bump will cause it to
gain volume. When I key the mic, it gets better for a little while. The fact that it gets better
on it's own with a mic keying gives me a small hint it might be a cold joint.

My old mobile works fine in the truck...

I might just get a new mobile...

It's frustrating me to no end.

73's !

[dud muck]

You hear it on your speaker too?

you said you have your radio wired directly to your battery, good.

Its possible the grounding strap connecting your engine block to your frame is corroded or otherwise becoming flaky.
The same goes for the strap between your battery negative terminal and the frame.

Check them out.
If its an older vehicle, just replace them.
Sandpaper the surfaces on the frame where the contact is made.

[Thisdude08]

That's the only place I am hearing it...on the CB speaker. It does not
go through the stereo & even the CB mounted on the dash won't bleed
over the stereo and it's right on top of it.

I'll check the ground straps...it's possible it could be that but if they were bad you would think
I would hear the whine or something on the stereo and I never do.

Appreciate the suggestion...will give it a look after work.

73's !

[Sheriff Bart]

how is the positive wire that's attached to the battery ran? Is it alongside the positive cable? Is it near the fender well? I would keep the ground on the frame and try to position the positive wire away from the heavy positive battery cable. Depending on what kind of mobile it is here's something else to try. You hooked your radio directly to the battery so it can get more amperage (because voltage is generally constant) look at your fuse panel. You should find some 30 amp circuits there and in some cases there will be a bus or an unused male connector adjacent to that fuse which will give you the same effect that you wire directly to the battery for.


73's

[Thisdude08]

The wire is kinda under the protected area of the hood & in through the passenger
side...will try the fuse thing. What still confuses me is why it is intermittent. If my wiring was in the wrong place
wouldn't it always bother the cb & not just sometimes? Anyway I'll try it &
see what happens....I checked the ground straps in the truck (It's an '04)
& seems fine...

I have tried grounding to the frame with the same result.

73's !

[Sheriff Bart]

for the intermittent... I would be guessing but it may coincide with the regulator turning the charging circuit on and off. Once the battery is at a certain amount of charge the regulator will sense it and the alternator stops putting out its rated output. Then once the level of charge drops the regulator signals the alt. to begin its charge cycle.

73's

[Thisdude08]

I understand but then why when I key the mic
does it go back to normal & why when I go over a bump does it return?
That's whats confusing me...

73's !

[Zumlin]

Check all the Grounds/ power leads for clean tight contact, or maybe the alternator brushes could be dirty also, I sprayed inside my alternator w/ CRC electrical contact cleaner with the engine off and let it dry a while. I was getting some weird intermittent noise from my ALT before I sprayed it. If that dont work somthing else is messin with ya..

[Sheriff Bart]

another thing to think about..I've read so many pro and con responses concerning the Cobra 200 that maybe you can start a thread asking whether anyone else using them is experiencing the same phenomenon.

73's

[Thisdude08]

Yeah Sheriff Bart & to think I bought it from the wrong place...before I knew about the forum & RA or any of the
other sponsors here...I'm screwed...royally I think...too bad too as I love the radio itself...

Will try those suggestions Zumlin...it's sure worth a try...appreciate the advice here..

73's !

[BtyMONSTER]

since you haven't fixed it yet ill go out on a limb and suggest trying a different antenna since you say it didn't happen on the bench . your 5000 ( a great antenna !! ) could have a short in the pl-259 , or , open braid in the shielding or being pinched or worn through the casing . if it still happens with a different antenna then its not the 5000 . not too difficult to replace the pl-259 or coax if it is . you could try another radio in the vehicle and see if the problem contours then you ll definitely know if its the radio or not....even a cheapie will do for testing . good luck .


[Please login or register to view this link]

[Thisdude08]

Hi Bootymonstor,

I actually have tried several radios...the Cobra 200, a Superstar 158 (RCI) & an older Cobra 148.
The whine is there with all of them.

I also tried an older K-30 antenna & still heard the whine.

It is pointing to the fuel pump as the whine is present for one second
when the ignition is in the acc. position. (but not actually running)

Ford did issue a TSB for a fix for this but not for my 2004 F-150. I saw the dealer yesterday
& we are going to try this fix anyway seeing that I'm sure it's not the radio
& 99% sure it's not the antenna.

It won't happen on the bench because there is no whine to pick up in the house
& therefor can't duplicate the problem.

I am getting this work done next Wednesday. I can't think of anything else to try
before then. I'll let you know what does happen & if you can think
of anything else to try I'll be glad to...meanwhile I'm keeping my fingers
crossed that this fix will do the trick.

If it does not work then my wife will kill me for putting more $ into CB stuff so if I don't
post after Wednesday you'll know why...(Only kidding)

73's !

Jim in Western VT
"Vermont's 509"

[dud muck]

It is pointing to the fuel pump as the whine is present for one second
when the ignition is in the acc. position. (but not actually running)

wow.. a month going on this.

Fuel pumps have generally be associated with RFI. Meaning the noise is radiated on radio frequencies.
Does this noise show up with S-meter movement on your CB?

Alternator whine, such as that caused by ground loops, is audio noise riding on the DC power feeding your radio, and is generally not an RF interference.

I just want to make the distinction between RF interference and audio noise on the DC power.

Good Luck!

[Thisdude08]

Dud Muck,

Yeah I know a month is a long time but between work & trying
different things time flies!

The alternator was unplugged for a few seconds & the noise was still there.
It can move the signal meter if it's loud enough but usually does not
move it too much. However it does put that "whine" behind anyone I'm talking to
especially longer distances which is very annoying.

I realize I might have 2 problems...fuel pump noise & alt. whine.
I'm hopeful though that the work done on Wednesday will yield something.

Thanks for the good luck wish...I also am hoping for the best.

73's !

Jim in Western Vermont

"Vermont's 509"

[linx]

I just posted a problem with a whine too. Good luck on yours. Mine's been going on since I started driving my current truck 2 years ago trying to figure it out. I probably have $2000 bucks in mine so far by changing complete setups and all the other odd/end crap. I'm going to read through this thread and see if anything can help my cause before I boycott CB radios and Ford trucks, lol.

[Thisdude08]

You might want to have the dealer perform the TSB even though
your truck may not be listed.
Or wait until I do it & I'll tell you if it worked or not.

Does it do that whine when you put the key in acc. mode with the engine off?
If so, it's like mine & it's the fuel pump.
Curious too if it changes intensity going over even small bumps. Mine will at times.
Also, does it ever work correctly? Mine did for 4 days!

After this if no luck my next step will be a different truck...probably a Dodge
but I'll cross that bridge if I get there...

73's !

Jim in Western Vermont

"Vermont's 509"

[linx]

You might want to have the dealer perform the TSB even though
your truck may not be listed.
Or wait until I do it & I'll tell you if it worked or not.

Does it do that whine when you put the key in acc. mode with the engine off?
If so, it's like mine & it's the fuel pump.
Curious too if it changes intensity going over even small bumps. Mine will at times.
Also, does it ever work correctly? Mine did for 4 days!

After this if no luck my next step will be a different truck...probably a Dodge
but I'll cross that bridge if I get there...

73's !

Jim in Western Vermont

"Vermont's 509"

Mine's only when the truck is running. Not at all with key in the ignition, and it doesn't matter if i'm sitting still or 4x4ing, lol...it's always there. Mine's never done right. Enough that I've changed my complete setup. I may retire this truck and buy a new one. It's a company truck...but I'm one of the tops at the company. I just don't know. My differance to yours is that mine's a Diesel so I don't think the fuel pump is an issue.

[Thisdude08]

Hi linx,

Yours sounds like alternator whine to me. I was told that comes in off the power wires.
What wiring configurations have you tried?
Also does it change tone as you speed up & slow down?

One thing that did help with some noises was when I shielded the power wires
with aluminum foil & shrink tubing.
However this does not help with fuel pump noise.

I totally wish you good luck cause I know how frustrating it can be.

Couple different people said to try this as it helped them with alternator whine & ignition noise:

[Please login or register to view this link]

I am tempted but wanna wait till after the TSB work on Wednesday to see where I stand
as I think mine is from the fuel pump.

73's !

Jim in Western Vermont

"Vermont's 509"

[Thisdude08]

Got done with the TSB work & the whine is cut down by about 50%.

They let me try the CB on a brand new truck & it too had whine.

I snapped a ferrite core around the bottom of the Wilson 5000
& that cut it by another 20% or so...but probably will cut my reception back a little too.

However what I'm losing in reception I might gain with less whine...not sure
but that's about all I can do....live with it. It'll get me on SSB more as it's
more tolerable that way.

73's !

Jim in Western Vermont
Vermont's 509