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Alabamakid
Junior Member
Username: Alabamakid
Post Number: 31
Registered: 1-2005
| | Posted on Friday, February 25, 2005 - 8:54 pm: | 
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I have tried everything. I have a RF ground on everything and I still have the NOISE. I have good coax ( Belden RG8X 97% shielded). What can I do to get rid of it? I am pretty sure that it is coming in via the antenna. |
Tech808
Moderator
Username: Tech808
Post Number: 5012
Registered: 8-2002
| | Posted on Friday, February 25, 2005 - 11:59 pm: |
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Alabamakid,
Try another antenna and let us know if the noise goes away.
And also try another radio with the antenna you have now and let us know if the noise goes away.
This information will help us to better try and help you with your problem.
Lon
Tech808
CEF808
N9OSN |
Alabamakid
Junior Member
Username: Alabamakid
Post Number: 32
Registered: 1-2005
| | Posted on Saturday, February 26, 2005 - 7:32 am: |
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I am going to work on it today. I will swap antennas and radios while I am out there.
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Alabamakid
Junior Member
Username: Alabamakid
Post Number: 34
Registered: 1-2005
| | Posted on Saturday, February 26, 2005 - 1:51 pm: |
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--The first thing I did was swap out my cobra 29 LTD with my cobra 25 LTD classic-- I still had the noise
--I put the 29 LTD back in and started swaping antennas
--with the astatic linear 3K I had significant noise and respectable SWR. CH 20 / 1.4
--with the wilson trucker 5000 I didn't have as much noise as the Linear 3K but SWR was not as good CH. 20 / 1.7
--With the good ole 102" SS Whip I had almost no noise at all. I could turn of my NB/ANL switch with the engine running and barely hear the engine noise at all. SWR was 1.1
I am not sure what this proves. I spent a lot of money on the Wilson 5000 and the Linear 3K, but if with the noise I have on the both of them I can't use them. Especially knowing that my radio is almost perfect all the way around with the 102"SS.
I can't think of anything else to ground. I grounded the exhaust earlier this week hoping that would help. I have the altenator housing grounded to the frame. I have the hood grounded. I have my tool box grounded. The bed grounded. I am out of Ideas and I really want to be able to run any of my antennas on my truck. Any help is greatly appreciated.
Tech 833 adds- With the coil type antennas, you have more antenna surface area near the vehicle, which in itself could be 'hot'. A vehicle is not TRULY grounded, there is NO static bleed off from a vehicle body or chassis. With the 102" whip, most of the antenna is further away from the vehicle itself. |
Alabamakid
Junior Member
Username: Alabamakid
Post Number: 35
Registered: 1-2005
| | Posted on Saturday, February 26, 2005 - 10:34 pm: |
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How do i eliminate noise from the fuel pump and the plug wires? |
Racer_x
Member
Username: Racer_x
Post Number: 55
Registered: 2-2005
| | Posted on Sunday, February 27, 2005 - 1:24 pm: |
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If you disconnect the antenna does the noise go away entirely? |
Alabamakid
Junior Member
Username: Alabamakid
Post Number: 36
Registered: 1-2005
| | Posted on Sunday, February 27, 2005 - 7:09 pm: |
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Yes. With the antenna disconnected I have absolutley no noise on the radio. |
Racer_x
Member
Username: Racer_x
Post Number: 59
Registered: 2-2005
| | Posted on Monday, February 28, 2005 - 12:47 pm: |
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It's definitley comming in through the antenna then.
Have you done what you can to ground the engine hood of your car? Run some tinned copper strap across the hinge from where it connects to the body to where it connects to the hood. That alone can solve the problem.
If that doesn't you'll have to determine where the noise is comming from and address it at the source. They make spark plug wires that supress RFI and bypass capacitors will get rid of RFI from motors of all kinds, and also help to get rid of alternator whine. |
Bc910
Intermediate Member
Username: Bc910
Post Number: 385
Registered: 7-2004
| | Posted on Monday, February 28, 2005 - 10:38 am: |
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Heck, stick with the 102. If it aint broke, dont fix it right?
BC |
Mdiver
Intermediate Member
Username: Mdiver
Post Number: 231
Registered: 11-2003
| | Posted on Monday, February 28, 2005 - 7:02 pm: |
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What kinda moble truck car do you have?
I agree with Racer X as he posted--
They make spark plug wires that supress RFI and bypass capacitors will get rid of RFI from motors of all kinds, and also help to get rid of alternator whine.
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Alabamakid
Junior Member
Username: Alabamakid
Post Number: 37
Registered: 1-2005
| | Posted on Wednesday, March 02, 2005 - 7:28 am: |
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I have the hood grounded with a stranded ground strap that is 12" long x 1/2" wide.
The altenator is ground to the frame using 12GA wire.
The set up is on a 96 Silverado.
I do have engine noise with the 102", I didn't think that I did at first. I do not know I how I came to the conclusion that I didn't. I could have bumped the RF gain knob while I was changing out the radios.
I put headers on the truck and this seems to have made the problem worse. (louder noise)
The noise does not accelerate with enginge RPM/s but it does have some pretty loud popping sounds in it.
The exhaust is also grounded using the same 12" long by 1/2" wide grounding straps. I hade the muffler shop weld these on when they were installing the headers.
The only way the noise is bearable is to turn the RF gain knob about 1/4 of a turn back. BY doing this I am missing a lot of RX though. The noise is up to mid scale on the meter. I have to filter out RX that comes in loud and clear with the engine off.
I am about to take the whole dang thing out and put it on ebay.
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Racer_x
Member
Username: Racer_x
Post Number: 77
Registered: 2-2005
| | Posted on Wednesday, March 02, 2005 - 3:35 pm: |
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If it got worse when you put headers on I'll bet the engine block's ground was changed. How it was grounded I don't know, but it's possible that it was getting a ground through the stock exhaust. Do what you can to get the block grounded to the frame.
I don't know how you would weld gounding strap to anything. Usually grounding straps are copper and I'm pretty sure you can't weld copper. You generally tin them with solder and bolt them to the frame somewhere. It's VERY important that they contact points are tinned. Copper and zinc (galvanized steel) or copper and steel aren't the best of metals to put nest to each other. There will be oxidation and the electrical connection will degrade quickly.
Pops are usually ignition noise. I don't know why it doesn't change with RPMs, but it should. Have you tried a new set of spark plug wires that have RFI supression? Do you have some kind of high performance spark plugs installed? They really make noise. I can tell when someone has split fire plugs 100's of yards away. |
Alabamakid
Junior Member
Username: Alabamakid
Post Number: 38
Registered: 1-2005
| | Posted on Thursday, March 03, 2005 - 5:48 pm: |
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Today on the way to work I noticed my radio had almost no eninge noise on it. I turned off the NB / ANL swith, turned the squelch all the way down, and turned the RF Gain all the way up and here were my findings
With the ANL/NB swith off I could still hear the popping noise, The ANL/NB switch filtered this out though.
With the ANL/NB switch on They engine noise was gone. The only noise I had was minimal RF noise that didn't even swing the meter to 1
The thing about today is that it was raining cats and dogs. I have heard about RF noise building up in radial tires and that it keeps getting worse until the tires get wet. I am going see if the noise starts getting louder when it dries up.
Has anyone else ever heard of this, had this happen or have any kind of experience with this at all. Does anyone know how to fix this, if this is the case?
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1861
Intermediate Member
Username: 1861
Post Number: 104
Registered: 2-2004
| | Posted on Thursday, March 03, 2005 - 6:28 pm: |
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YEP , HAVE YOU EVER SEEN PIECE OF CHAIN HANGING UNDER CAR CLICKING AGAINST ROAD ? HAVEN,T SEEN IT IN LONG TIME , BUT USE TO BE FAIRLY COMMON |
Racer_x
Member
Username: Racer_x
Post Number: 87
Registered: 2-2005
| | Posted on Thursday, March 03, 2005 - 7:16 pm: |
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I've seen chain on trucks, but not cars. I do see straps hanging from cars occasionally. They seem kind of rigid and heavy. I think they're made out of rubber.
Alabamakid - It sounds like the ground on your truck suddenly got better with moisture. Next time you have it really badly, take it to a car wash and spray down the undercarriage well. If it suddenly goes away, you need to get in there and make sure the ground connections are good. |
Alabamakid
Junior Member
Username: Alabamakid
Post Number: 39
Registered: 1-2005
| | Posted on Thursday, March 03, 2005 - 7:53 pm: |
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I appreciate all the input you guys have given me. I am going to try to carwash thing as soon as the noise comes back.
Racer x -- You had ask about the bround braid I used on my exhaust.
"I don't know how you would weld gounding strap to anything. Usually grounding straps are copper and I'm pretty sure you can't weld copper. You generally tin them with solder and bolt them to the frame somewhere."
I went to carquest and what I found is a braided stapped that is copper (it is tinned of course) It is 12" long, 1/2" wide, and flat. On both ends it has a flat terminal that is crimped/pressed on. The end terminals have a hole through the center for a battery post to go through. Carquest list them as a battery cable, but if you ask for ground braid this is what they give you. I also have the hood of my truck grounded using one of these. I am not sure what the end terminals are made of but the muffler shop was able to tack weld it to the frame and the mufflers. Before I used them I tested them with a multimeter and go 0 resitance. They seemed like a pretty good ground strap to me.
Do you think I should replace them with something else? |
Racer_x
Member
Username: Racer_x
Post Number: 89
Registered: 2-2005
| | Posted on Thursday, March 03, 2005 - 8:54 pm: |
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I've never seen one of those up close before, so I can't say what I really think of it. If it was able to be welded then it's a good connection at that point, but I don't know how good the connection would be from the braid to the flat terminal. If it's made as a battery cable then I would guess it's got to be pretty good.
The thing about crimped on connections is that after they are subjected to age and weather they tend to oxidize and become poor. That's why soldering is better.
Play around with the multimeter and see what the resistance is between the firewall and the engine block, the engine block to the negative battery terminal, and the body to the negative battery terminal. If it's not zero then you may have found your problem. |
Al_lafon
Junior Member
Username: Al_lafon
Post Number: 31
Registered: 3-2005
| | Posted on Thursday, June 02, 2005 - 9:28 pm: |
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Hello all had to do a lot of gounding on my chevy
malibu 2004 frist place i looked trunk to body was like 185k ohm. also did block to subframe
then body to subframe PS on the block gnding look
for bolts to use as close to the frame as you can
get i used a engine mount.
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