I'm doing over my panel, installing 2 Skyviews. I'm also making a bunch of changes to the electrical system. I read through Bob Nuckells book. There is one thing I can't seem to find, so I figured I'd ask here. I know when grounding the shielding of headset and mic wiring, your supposed to ground the end at the radio and leave the jack end unconnected. For the strobes, same thing ground at the power supply and not at the light. How about the alternator. I have a shielded field wire, should it be grounded behind the panel and not at the alternator, or visa versa. I guess the question is, should shields be grounded always nearest the panel and radios or the source of the noise, the alternator.
Van's Air Force
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Electrical Shielding Question
- Thread starter RFazio
- Start date
I agree with John that you don't need a shielded field wire - I'd probably just not ground the shield if it is already installed.
I also agree that for AUDIO lines, you generally only ground the shields at the audio panel end (if you have an audio panel). For data lines (RS-232 and ARINC 429 for example), I like to follow the manufacturer's drawings EXACTLY - good drawings will tell you where to ground - some get it at both ends.
Paul
I also agree that for AUDIO lines, you generally only ground the shields at the audio panel end (if you have an audio panel). For data lines (RS-232 and ARINC 429 for example), I like to follow the manufacturer's drawings EXACTLY - good drawings will tell you where to ground - some get it at both ends.
Paul
The technique I follow with shields is that any current which is induced in the shield must return to the source of the current. So with a strobe, there is a high energy signal being transmitted on the twisted-pair within the shield. Any of that induced current must be conducted back to the strobe PS by the shield. If the shield was not attached at the strobe PS end, the induced current would have to find its way back to it, which could then radiate all along whatever its return path.
The reason for using twisted pair is along the same line. Provide a metallic return from the load to the PS and all of the current out and back to the load will generated cancelling magnetic fields so that there is no electromagnetic radiation. Always ground the shield at the signal source, whatever it may be!
The reason for using twisted pair is along the same line. Provide a metallic return from the load to the PS and all of the current out and back to the load will generated cancelling magnetic fields so that there is no electromagnetic radiation. Always ground the shield at the signal source, whatever it may be!
Where do I find said book. Google and Amazon are not showing it.
Dan try aeroelectric.com
http://www.bandc.biz/theaeroelectricconnection12theditionboundbook.aspx
Lots of additional info from Bob here: http://www.matronics.com/aeroelectric/articles.html
Best,
-Jim
If I read Bob right
In the ground section of Bob's book. He says to insulate the headphones and mic jacks from the airframe and to connect the low side (-) to the shield or a separate wire and run it all the way back to where the interphone/radio is grounded. Pg 5-7 in my book.
Peter Richmond
In the ground section of Bob's book. He says to insulate the headphones and mic jacks from the airframe and to connect the low side (-) to the shield or a separate wire and run it all the way back to where the interphone/radio is grounded. Pg 5-7 in my book.
Peter Richmond
