Curing RF noise issues in 2003 Silverado with 5.3L engine
I have been researching noise and RFI issues in diesel trucks as I am looking in to getting one. In my research I came across W8JI's website. He has an article on there about curing noise to his HF radio in his Powerstroke Diesel F-250.
I decided to take his techniques and apply them to my current truck - a 2003 Silverado 1500 Z71 with the 5.3L gas engine. I am happy to report that the techniques work! My noise on HF is substantially reduced. I was playing around on 80 meters Thursday night with my IC-718 as it is the most affected by noise in the truck out of all the HF rigs I have, and 80m is the lowest band I can tune in the truck. The lower the band the more affected the rig is by noise. When I tuned up on 80 and listened the majority of the noise was just normal band noise. There was little difference between the truck running and not running! Before my work the 718 was just about worthless in the truck.
Today with the TS-2000 after I replaced the coax to the antenna the noise is totally gone. I switched to AM trying to hear some ignition pops, but nothing. Absolutely nothing!
The first technique I adopted was to tie the cab and bed together to bring them as close to the same ground potential as I could. W8JI mentions using one ground, but seeing as my braid is smaller than what he used I decided to do two - one on each side.
Left side:
Right side:
I used 1/2" tinned copper braid. I filled each end with a lot of solder so it was nice and stiff (plus it ties all the strands together better). For screws I used stainless steel self-tapping screws and external star washers, just like W8JI did. I got my hardware at Roush Hardware. The star washers eat through paint and surface rust to make a better electrical connection. The washer goes in between the strap and the material it is attaching to, not on top of the strap.
Stainless steel hardware:
The second technique I used was to ground the exhaust pipe to the frame. I don't know that I did this the best way, but this is how I did it. I used the same stainless steel hardware and 1/2" strap. I drilled through both the frame and the exhaust pipe. Then I installed the strap.
Muffler ground:
Apparently, the exhaust pipe makes for a nice antenna for any RF generated at the engine. W8JI describes this towards the bottom of the afore mentioned page. By grounding the exhaust pipe it puts a stop to the radiating properties that the exhaust pipe has.
Lastly, I made a new ground connection to my screwdriver antenna mount and replaced the cable and sealed it. The old ground was exposed and used C clamps to attach it to the mount and the frame HI. Needless to say, it was a poor ground at best. The coax was cheap RG-8x and I never worried about sealing it. Based on experiences in the past I am sure the old cable was shot - it has been in the truck for the past 4 years! Now I know how to do it right.
The ground strap is sort of hidden by the mount tube, but you can see where it attaches to the body:
I used more of the same stainless steel hardware to attach the ground strap, this time to the BODY. Since I tied the cab and bed together the body will make for a great ground/counterpoise. I never throught of drilling through the body before, but I figured I could place it somewhere out of sight and it wouldn't matter.
Now - if you are wondering why all of these ground connections are black, heres the trick =
That stuff is called "Plasti-Dip". It is liquid tool handle grip. I got mine from Home Depot. Basically the stuff comes as a liquid in a can and you brush, slap, drip it on or dip your item in it. When it dries it is like a latex coating, only MUCH stronger. It flexes and stretches so it won't crack. The whole can I got was less than $7. In fact, it says right on the can that it can be used for electrical insulation! I suspect this stuff will last a while under the truck.
If you use Plasti-Dip for coax connections be sure to wrap the connection with electrical tape first. This way if you need to remove it you just slice all the way through the coating and the tape and peel it off. The dip by itself might be harder to remove.
Update: July 1 2009
My ground line between the exhaust pipe and frame broke somewhere along my Canada trip this year. I started hearing noise on 6m that sounded like fuel pump noise (9-pulse rise in the noise floor). It started at about S1-S2 when we hit the road on the way home and by the time we hit Duluth, MN the noise was S9 on peaks.
The line broke on the exhaust pipe side. I attribute it's breaking to it being too short. Before I put a new one on I moved the exhaust pipe around to see how much play it needed and gave it a little more. This way there is no stress on the ground line now.
The Plasti-Dip works great! It is very tough stuff. I had to use my knife and slice in to it as much as I could, but because of the angle of everything I couldn't cut it all. So I just stretched it until it broke or I could get a knife on it. The stuff is VERY tough - even after a year under the truck.
The frame connection was as clean and shiny as it was when I put it on. The exhaust pipe side was corroded and was pulled apart from the exhaust pipe (from being too tight I imagine). The stainless steel hardware was fine, just a bit dirty.
I put a new line on that is about 3" longer than the old one, and folded back on itself with a loop to give it some freedom to move. Now I can move the exhaust pipe further than it would ever move going down the road and the line still won't get tight. Lets see how long this one lasts!
There is absolutely no degradation of the cab/bed lines. They haven't moved and are sealed up great.
I decided to take his techniques and apply them to my current truck - a 2003 Silverado 1500 Z71 with the 5.3L gas engine. I am happy to report that the techniques work! My noise on HF is substantially reduced. I was playing around on 80 meters Thursday night with my IC-718 as it is the most affected by noise in the truck out of all the HF rigs I have, and 80m is the lowest band I can tune in the truck. The lower the band the more affected the rig is by noise. When I tuned up on 80 and listened the majority of the noise was just normal band noise. There was little difference between the truck running and not running! Before my work the 718 was just about worthless in the truck.
Today with the TS-2000 after I replaced the coax to the antenna the noise is totally gone. I switched to AM trying to hear some ignition pops, but nothing. Absolutely nothing!
The first technique I adopted was to tie the cab and bed together to bring them as close to the same ground potential as I could. W8JI mentions using one ground, but seeing as my braid is smaller than what he used I decided to do two - one on each side.
Left side:
Right side:
I used 1/2" tinned copper braid. I filled each end with a lot of solder so it was nice and stiff (plus it ties all the strands together better). For screws I used stainless steel self-tapping screws and external star washers, just like W8JI did. I got my hardware at Roush Hardware. The star washers eat through paint and surface rust to make a better electrical connection. The washer goes in between the strap and the material it is attaching to, not on top of the strap.
Stainless steel hardware:
The second technique I used was to ground the exhaust pipe to the frame. I don't know that I did this the best way, but this is how I did it. I used the same stainless steel hardware and 1/2" strap. I drilled through both the frame and the exhaust pipe. Then I installed the strap.
Muffler ground:
Apparently, the exhaust pipe makes for a nice antenna for any RF generated at the engine. W8JI describes this towards the bottom of the afore mentioned page. By grounding the exhaust pipe it puts a stop to the radiating properties that the exhaust pipe has.
Lastly, I made a new ground connection to my screwdriver antenna mount and replaced the cable and sealed it. The old ground was exposed and used C clamps to attach it to the mount and the frame HI. Needless to say, it was a poor ground at best. The coax was cheap RG-8x and I never worried about sealing it. Based on experiences in the past I am sure the old cable was shot - it has been in the truck for the past 4 years! Now I know how to do it right.
The ground strap is sort of hidden by the mount tube, but you can see where it attaches to the body:
I used more of the same stainless steel hardware to attach the ground strap, this time to the BODY. Since I tied the cab and bed together the body will make for a great ground/counterpoise. I never throught of drilling through the body before, but I figured I could place it somewhere out of sight and it wouldn't matter.
Now - if you are wondering why all of these ground connections are black, heres the trick =
That stuff is called "Plasti-Dip". It is liquid tool handle grip. I got mine from Home Depot. Basically the stuff comes as a liquid in a can and you brush, slap, drip it on or dip your item in it. When it dries it is like a latex coating, only MUCH stronger. It flexes and stretches so it won't crack. The whole can I got was less than $7. In fact, it says right on the can that it can be used for electrical insulation! I suspect this stuff will last a while under the truck.
If you use Plasti-Dip for coax connections be sure to wrap the connection with electrical tape first. This way if you need to remove it you just slice all the way through the coating and the tape and peel it off. The dip by itself might be harder to remove.
Update: July 1 2009
My ground line between the exhaust pipe and frame broke somewhere along my Canada trip this year. I started hearing noise on 6m that sounded like fuel pump noise (9-pulse rise in the noise floor). It started at about S1-S2 when we hit the road on the way home and by the time we hit Duluth, MN the noise was S9 on peaks.
The line broke on the exhaust pipe side. I attribute it's breaking to it being too short. Before I put a new one on I moved the exhaust pipe around to see how much play it needed and gave it a little more. This way there is no stress on the ground line now.
The Plasti-Dip works great! It is very tough stuff. I had to use my knife and slice in to it as much as I could, but because of the angle of everything I couldn't cut it all. So I just stretched it until it broke or I could get a knife on it. The stuff is VERY tough - even after a year under the truck.
The frame connection was as clean and shiny as it was when I put it on. The exhaust pipe side was corroded and was pulled apart from the exhaust pipe (from being too tight I imagine). The stainless steel hardware was fine, just a bit dirty.
I put a new line on that is about 3" longer than the old one, and folded back on itself with a loop to give it some freedom to move. Now I can move the exhaust pipe further than it would ever move going down the road and the line still won't get tight. Lets see how long this one lasts!
There is absolutely no degradation of the cab/bed lines. They haven't moved and are sealed up great.
posted by Steve at
3:39 PM
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