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Author Topic: ignition noise in vehicle frame??  (Read 1524 times)

Posts: 90

« on: September 07, 2003, 08:44:49 PM »

Hi again....

I'm still dealing with a severe noise problem in my 2003 Dodge Dakota pickup truck.   Every thing I hear or read says to make sure everything is grounded.  

So far,  I have the exhaust pipe and tail pipe grounded in four places.   No difference in noise level.   The truck bed is bolted to the frame in six places, so I didn't bother installing ground straps.  

While messing around and searching for answers,  I decided to touch the antenna coax to the body and/or frame.  Guess what....the ignition noise gets louder!!
So, I'm thinking out loud to myself....why the heck am I grounding stuff to rid the noise, when the noise is in the frame??!!??!!  
Next,  I took a small portable AM radio and tuned it to 1600 kcs and held it close to different spots on the truck's frame.  Believe it or not, there are spots when the noise almost disappears and others where is quite noticeable.
That's when I gave up and said forget it til tomorrow.  

Question is:  How do I eliminate the ignition noise from the truck frame??   And body??  

I removed the 20 meter Hustler mobile antenna from the mount and while hand-holding it, I moved the loading coil over areas of the vehicle.  Ignition noise everywhere!!

What is really upsetting is:  My Son happen to stop by and parked next to me on the driveway.  He drives a Ford Explorer.   I held the antenna coil over his vehicle and NO NOISE..!!!    He suggested I use his vehicle whenever I wanted to go mobile.   I felt like kicking him in the.....


Posts: 114

« Reply #1 on: September 08, 2003, 10:50:45 AM »

" truck bed bolted to the frame" If you paint the frame and paint the bed then bolt the two together you will not get an electrical connection. Don't assume , each part of the vehicle should be grounded to the frame and each connection you should scrape down to bare metal then use anti-oxidant goop to maintain a good connection. In addition the more parts you ground the bigger the ground plane and the stronger your signal.

Posts: 10248


« Reply #2 on: September 08, 2003, 11:41:34 AM »

Bonding ALL body parts is an important step in reducing noise, but by no means the only step. Proper wiring, good antenna mounts, and antenna matching are just a few of the more important ones.

I wrote a few articles about noise abatement a while back which may help. Look in the article section here on for numbers 4407, 4423, 4424, and 4623.

Alan, KØBG


Posts: 90

« Reply #3 on: September 09, 2003, 09:28:40 PM »

By golly, I think I'm getting somewhere!   I spent most of the day bonding the pickup cab to the frame and also the bed.  My ignition noise level on 75 and 40 meters is S-1 to 2.  Kinda hard to tell, because there's been a lot of atmospheric noise in the area lately.   This is a HUGE improvement from the S- 5 to 7 I was getting!   However, I still am getting about an S-4 on 20 meters.  Not sure why this is, but maybe someone has an answer to that problem.
Tomorrow, I plan on installing 5 or 6 more ground straps, in hopes the noise will drop even more.  
I have my Hustler antenna mounted on the bumper and I'm sure the bumper was painted before it was installed.  So, I'm gonna figure out how to ground the bumper on both sides to improve that ground situation.  

For those new to installing an HF rig in a vehicle, each ground strap you install, lowers the noise level.  The key word here is "each".   You won't notice much of a change with one strap, but add a few more and you can tell the difference.  At least that's what I'm finding out.  

Roland (WB0AXN)
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