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Discussion Starter #1
I just finished installing my CB in the center console. After cutting the hell out of everything that is under the black panel the CB is in place. I used the speaker from West Marine and that fits like glove, it looks like it was made for the hole. But once I started the engine I heard the alternator over the speaker.
I guess there is a bad ground.



This CB thing is really starting to get me down....I never had to work this hard to install a CB ever...
then com e to find out it has a ground problem. I guess it will be on the list of things to do tomorrow.
 

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READ THIS, MAYBE IT WILL HELP YOU.
What you are hearing is alternator whine. This may be caused by several scenarios.


I assume that you are using one of the "switched" spares located near the fuse panel. There is a ground bar just under the fuse panel. You may need to drill a small hole in order to use a screw holding the negative lead. It is important this lead have a low resistance to ground. If the coax shield to the antenna is grounded to the body at the termination point, a ground loop may exist between the two grounds, fuse panel area and antenna location. The coax shield ground should be grounded at the antenna location. The ground loop condition may exist if the ground connection at the fuse block area is resistive.


With the radio on, disconnect the antenna from the radio. Does the alternator whine stop? If it does NOT, try installing a choke type noise eliminator on your positive D.C. lead near the radio. These have been available at Radio Shack over the years. It will look like a small transformer with some condensers etc.


If the alternator noise STOPS when you disconnect the antenna lead, remove the ground connection at the antenna end if it is connected to the body. DO NOT TRANSMIT. If the noise stops, you have a poor connection between THAT part of the vehicle body to frame ground. Most alternator's diodes do not radiate much R.F. up this high in frequency so it is probably a ground loop caused by a poor body ground.


There is a fix but Radio Shack won't have what you need.


Most alternators used on Hummers are of the "self excited" type. Without going into detail, it makes noise elimination fairly easy since there is only one heavy wire leaving the unit. Since we are dealing with high current output at this point, the standard coaxial condensers from Radio Shack will be useless. They will not handle the current. Go by a Motorola communications shop and tell them about the alternator whine. More than likely, they will have a 100 plus amp. coaxial condenser that you will need. This thing ain't cheap so try everything else beforehand. This device goes in series with the main D.C. lead from the alternator. SOLDER the lugs that are used to connect this device. VERY IMPORTANT.


The noise heard when running the heater is caused by the brushes in the motor. Unfortunately, this can be normal in most installations but there is a remedy.


Install a .5 MFD 100 to 250 volt tubular capacitor to the main D.C. lead at the motor location as follows:


You will notice this capacitor has a black ring at one end. This end goes to the ground nearby or the negative lead of the motor. The other goes to the main +12V. lead going in the motor assembly. This capacitor is not polarized in the usual sense, but the "outside foil" is connected to the end with the ring. Maximum noise reduction will be had with the ring side connected to ground.


Some motors' outside cases are not at ground potential and this can also be a source of noise radiation. Check for continuity to ground using an ohm meter by placing one lead to the motor case, the other to ground. Use the voltage scale (12V) first before the Rx1 scale to make sure there is no voltage present as this could "pop" your meter movement. If there is no continuity to ground and no voltage potential, try connecting a wire from the motor case to the nearest "body" ground. Most of these motors have screws holding their cases together. Be careful when loosening these screws since the end case bearing assemblies are sometimes centered by the tightening of these bolts.


As with the the capacitor above, the maximum noise elim
 

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Discussion Starter #3
green95chevy,


This is some great info!!! Thank you, I plan on taking this on tomorrow. Hope it just a ground thing.


Thanks again!
 

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GREEN95CHEVY said:
I assume that you are using one of the "switched" spares located near the fuse panel.

where can i locate these switched spares?
 

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THEY SHOULD BE SOME ON THE FUSE PANEL " SLOTS NOT BEING USED"
 

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Discussion Starter #6
Those slots have power...I thought they were empty.


Anyway I fixed the noise problem....now my SWR is all over the place I think the COAX is crimping behind the radio when it is in the dash.



Football for now...I check it afer the game.
 

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NoWake200 said:
Football for now...I check it afer the game.

You mean there is football on today? Who is playing?



Darn! Not a TV in sight!
 

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Discussion Starter #8
I hate to tell you this, but you missed some good games.



The CB is up and running...I mounted the antenna hardware backwords in turn shorting out the antenna. That gave me some really bad SWR reading. Now ch1 is reading 1.8 ch20 reading 1.7 and ch40 reading 1.9. I have a fiberglass wip and worried about taking to much off. I also put a 90 on the ant input giving me a much nicer install.
 

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NoWake200 said:
I just finished installing my CB in the center console. After cutting the hell out of everything that is under the black panel the CB is in place. I used the speaker from West Marine and that fits like glove, it looks like it was made for the hole. But once I started the engine I heard the alternator over the speaker.
I guess there is a bad ground.



This CB thing is really starting to get me down....I never had to work this hard to install a CB ever...
then com e to find out it has a ground problem. I guess it will be on the list of things to do tomorrow.


Where did you end up mounting it, because I plan on buying a new 04 with bucket seats, with the center console, and to be honest there doesn't look like theres to much of any place to mount a brake controller let alone a CB, I was looking threw J.C.Whitneys catalog and they carry some different types of overhead shelves where a CB and speaker could be mounted, does anyone on here have one of these in there trucks?.
 

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Discussion Starter #10
I'll take a picture of it todoy and post it....it requires a BUNCH OF CUTTING but once it is in the CB does look good.
 

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keystonekid said:
Where did you end up mounting it, because I plan on buying a new 04 with bucket seats, with the center console, and to be honest there doesn't look like theres to much of any place to mount a brake controller let alone a CB, I was looking threw J.C.Whitneys catalog and they carry some different types of overhead shelves where a CB and speaker could be mounted, does anyone on here have one of these in there trucks?.

Check out this thread for several options and pics:


http://dieselplace.com/forum/forum_posts.asp?TID=2114&PN=3
 
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