What would you experts suggest? I run wire from a spark sensor clipped to a spark plug wire into the car to use with a data logger as RPM input. The AM radio reception has suffered as a result. Is there something (like a sleeving product) to cover the wire with to stop or reduce the RF interference? Or a special kind of wire?

 

That is interesting. Does it have to be off of a spark plug or can it be off the vechicle speed sensor VSS or maybe off of the tach wire? Those two wire will not give off any RF.

There are some products out there to shield the wire and products to shield the radio itself. Sorry I am not sure where to get them though. But I will check with one of my suppliers though to see if they have anything.

 

Thanks. This particular data logger (Race-Technology DL90) calls for the RPM input to come from the spark, but I have a suspicion that a more skillful electronics wrencher could figure something else out and use one of the famous white wires inside the dash that carry the rpm signal. Apparently the Porsche boys can use an input off their OBDII connector with a special cable.

 

Option one is to shield the existing wire. You need to ground the shield at both ends. Option two would be to just buy some shielded wire, and again ground the shield at the ends. That would be easier and cheaper.

Try this link to shield the existing wire: http://www.newark.com/NewarkWebComme...jsp?id=02F4316

02F4316 is the part number in case the link doesn't work.

 

[QUOTE]You need to ground the shield at both ends. /QUOTE]

Whatever you do, do NOT ground it at both ends. This will eliminate the purpose of the shield. I work with sensitive electronics systems and have seen ground loops caused by shielding that is grounded on both ends. It's a major PITA to go back, troubleshoot the problem, only to find that it was a ground loop created by something like this. Hope this helps.

Mark

 

Where can I get shielded wire? I can easily replace the wire, probably more easily that shielding the existing wire.

 

Fasthotrod,

How do you figure you're gonna get a ground loop? Ground is ground, the world around. The purpose of shielding is to supress radiant EMI- think Faraday cage, in which the idea is to provide a path to ground before the radiant noise can effect any circuitry.

I'm interested in your experiences.
Jared :flag

 

Jared,

Oh how I wish you were correct. It would make my life sooooo much easier. There is no such thing as "a ground is a ground the world around." I don't want to sound like I'm flaming you, because that is not my intent.

Here is a quote I found giving a good definition of what a ground loop is:

"A ground loop occurs when there is more than one ground connection path between two pieces of equipment. The duplicate ground paths form the equivalent of a loop antenna which very efficiently picks up interference currents. Lead resistance transforms these currents into voltage fluctuations. As a consequence of ground loop induced voltages, the ground reference in the system is no longer a stable potential, so signals ride on the noise. The noise becomes part of the program signal.

This is a great description of a ground loop. I could get into this more if you want me to, or you could do a quick Google search and get a lot more information. (and not put our fellow forum members to sleep... )

As for my experiences, I think it would not be appropriate in a public forum to say exactly where I work today, or whom I have worked for in the past. I will say that I have been working in the electrical power industry for over 14 years, and have been an audiophile for much longer. I have worked all over the United States, as well as in South East Asia. (Japan, Korea, Okinawa, Guam, and the Philippines.)

I worked for a major electronics corporation in Japan that was a "pioneer" in the home and car audio electronics. When I came back to the United States, I worked for the world leader in Uninterruptible Power Systems installing and testing Critical and Essential Power systems in excess of 3 megawatts per facility... which led to my current employer. As for today, let's just say that I work for an agency that provides a safe and efficient national airspace system.

:flag

If you would like more information, feel free to reply here or send me an e-mail. Thanks!

Mark

 

Mark,

That UPS company wouldn't have happened to be Exide->Yuasa->Enersys, would it? I gave those bastards many sweaty hours, and ultimately got laid off as a result of the telecom collapse- last to get hired, first to get fired, right? Other guys in the crew had foul attitudes that management knew about, but according to the boss, "They had families, and I didn't." Yeah, I'm slightly bitter... I bought my Vette two weeks before getting the can (over the phone, I might add!)

However, getting laid off was the best thing to happen to me- it gave me the chance to go back to school for EE. I asked a prof this ground question today, and he gave me the same answer you typed- due to resistance there may be a potential difference, which could cause noise. So I learned something! Thanks for pointing it out; every tip will make me more knowledgable in the field!

Jared :flag

 

Jared,

Glad to hear that you learned something! I find that I learn a lot from people if I can take it in like a sponge. To answer your question about Exide/Yuasa/Enersys... Exide was a parent company years ago, long before Yuasa came into the picture. They were a battery manufacturer and doing well for themselves when some engineers decided to come up with these wacko things called UPS's.

As time went on, the folks that ran the battery department thought that they should focus only on batteries... and the UPS engineers knew critical power systems were going to bust wide open... so they parted ways. Exide stayed with the batteries, and Exide Electronics was born unto itself. They kept up a "relationship" for years, pimping each others products.

So actually, Exide Electronics is not Exide/Yuasa/Enersys. Exide Electronics became Powerware a while back, was bought and sold a few times by BTR, Invensys, and recently purchased by Eaton. Exide battery teamed with Yuasa and became Enersys a while back.

So to answer your question, yes I worked for Exide Electronics. When I worked for them, it was a wonderful company that had a small business feel. (I actually got Christmas cards signed from the president and his wife. Not some stamped, BS, my secretary filled it out stuff either.) I left shortly before the company was sold the first time.

As for your situation, I'm sorry to hear it. Companies can have weird ways of dealing with their employees at times. It might suck right now, but as you said: it's the best thing that could have happened. Stay with school, keep your attitude positive, and network as much as you can. You'd be surprised how far that will get you.

Mark

p.s. Shoot me an e-mail. I might be able to point you in the right direction for employment when you wrap up your degree.