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Author Topic: Pictures RF Bonding Pickup Truck  (Read 5220 times)
NI0Z
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« Reply #15 on: November 03, 2011, 08:02:17 AM »

Thanks, these are nice pictures!

I am going to see if I can find some of the sources of the interference with a little E100 SW radio.  I have done this before in my house and found some nasty noise generators that allowed me to clean up my noise floor by about 14DB overall through grounding and eliminating the culprits. 

I was amazed to see how much noise my daughters cell phone made while charging!  Keyboards cause more noise than the computers themselves.  Lots of things have occilators and we don't realize it.  I discovered one morning that my wife running on the treadmill caused over 10DB of increased overall noise on 20M.

Given that the average modern vehicle has a plethora of electronics, it's no suprise that there are serious issues.  Heck, I didn't even know before this that the exauhst system was a noise source.

I think noise ellimination is missed by a lot of people.  ARRL says chapter 16 in the RFI book addresses some of these issues and even specially talks about hybrid vehicles in one part.

I do believe I will make some progress on this over the weekend, how much is what remains to be seen.

NI0Z
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NI0Z
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« Reply #16 on: November 03, 2011, 10:26:45 AM »

Took the shortwave radio with me when I went to lunch, at least two of the major noise sources are both the electric and the gas engine, they are both super obvious to here on the shortwave and I can here the whine of them winding up and down. 

Not sure that even if I find a way to suppress the engine whine that I will solve all my problems as the static level also goes up with the engine as well.  Not experienced enough to know that if I address what sounds like alternator whine that it will address the bulk of the noise issue or not.

Something really interesting I observed is that all noise goes away when I am at a stop and pressed down hard on the breaks.  Anyone know why that might be?  It's like the breaks when engaged create a ground of the chassis.  If that's the case and I strap the corners of the vehicle and the bed and antenna, there may be hope.

Well, the lunch trip was to buy some braided grounding strap for my weekend work, so I will see what I can accomplish!

NI0Z
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NI0Z
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« Reply #17 on: November 05, 2011, 05:32:32 PM »

Sometimes things just are what they are.  Today's vehicles are designed on to interfere with AM, FM broadcast radio, sattelite and 6M or higher frequencies. 

A careful look at the facts show that most vehicles don't suppress frequencies between 1.5-30mhz and that's all there is two it.  I was able to filter out engine while with grounding and ferrites, but something else is causing borad spectrom noise to be broadcast to my antenna.

I suggest anyone read the AARL RFI book before they think about HF in their vehicle.  I have no doubt many won't care about the side effects and damage bonding can cause to their vehicle, but for the few that bought theirs with the idea of it lasting many years, you might want to know some of the issues with bonding.

Thanks to all here for your help!

NIOZ
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GOLDTR8
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« Reply #18 on: November 06, 2011, 08:22:45 AM »

Sometimes things just are what they are.  Today's vehicles are designed on to interfere with AM, FM broadcast radio, sattelite and 6M or higher frequencies. 

A careful look at the facts show that most vehicles don't suppress frequencies between 1.5-30mhz and that's all there is two it.  I was able to filter out engine while with grounding and ferrites, but something else is causing borad spectrom noise to be broadcast to my antenna.

I suggest anyone read the AARL RFI book before they think about HF in their vehicle.  I have no doubt many won't care about the side effects and damage bonding can cause to their vehicle, but for the few that bought theirs with the idea of it lasting many years, you might want to know some of the issues with bonding.

Thanks to all here for your help!

NIOZ

What do you mean by bonding issues long term

KD8NNU
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NI0Z
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« Reply #19 on: November 06, 2011, 08:36:44 AM »

Bonding allows an electrical current to flow across the different metals in you vehicle.  Two things here, different metals accelerate rust and break down when they are connected together as does the electrical current.  If I don't quite have that right, you can read all about it in chapter 16 on the ARRL RFI handbook.

Best wishes!
NI0Z
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K0BG
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« Reply #20 on: November 06, 2011, 12:47:39 PM »

Chapter 16 of the ARRL Handbook is all about Digital Modes.

As for your Bonding issues Mark..... The only item on a modern vehicle that you really can't "bond" in the usual sense, is the radiator. It can be bypassed safely with a cap or two, as long as they aren't too high of a capacitance. Doing so doesn't help much by the way.

Bonding the hood, trunk (if any), and the exhaust system isn't going to cause them to corrode, and fall off into the street! In fact, if you measure their DC resistance to their surroundings, you'll find a fairly good DC ground. But, a DC ground doesn't help the flow of RF, hence the bonding.

Incidentally, I wrote the part of the ARRL Handbook (Chapter 29) which covers bonding.
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NI0Z
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« Reply #21 on: November 06, 2011, 03:58:14 PM »

http://www.arrl.org/shop/The-ARRL-RFI-Book-3rd-Edition

3rd Edition
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