[RFI] nissan spark gap

Cortland Richmond ka5s@earthlink.net
Fri, 8 Mar 2002 17:28:38 -0800

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<DIV><FONT face="Arial CE" size=2>Tom,</FONT></DIV>
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<DIV><FONT face="Arial CE" size=2>Seems like you have more signal than your probe can handle. </FONT></DIV>
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<DIV><FONT face="Arial CE" size=2>Try using a shielded loop. If you do not have one, you can make one by stripping about three inches of braid from the end of a piece of RG58,&nbsp; then stripping about 2.5 inches of insulation off the center conductor. Make a loop about three inches across with the SHIELDED part of the coax below the stripped wire, and see where the bare center conductor goes. Remove the outer insulation from the coax at that point and wrap the bare center conductor around the coax braid. Tape it up&nbsp;there. Now you have a serviceable shielded loop.</FONT></DIV>
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<DIV><FONT face="Arial CE" size=2>This will show you where RF&nbsp;_current_ is flowing. If it is too sensitive, use an attenuator, or make the loop smaller in diameter. It is used close in to wire and bodywork to tell which way current flows. A wire with current in it will give maximum response with the loop parallel to the wire. You can pinpoint a wire as a source by placing the loop next to it and rotating it 90 degrees. If the wire is a source, the noise&nbsp;will go down as&nbsp;the loop's&nbsp;plane becomes perpendicular to the direction of the wire.</FONT></DIV>
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<DIV><FONT face="Arial CE" size=2>Another thing you can do with this is, put a snap-on ferrite on the loop, and then clip the ferrite to a wire you want to evaluate. The ferrite will concentrate&nbsp;fields so only the wire's contribution is picked up.</FONT></DIV>
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<DIV><FONT face="Arial CE" size=2>Good hunting!</FONT></DIV>
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<DIV><FONT face="Arial CE" size=2>Cortland</FONT></DIV>
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<DIV style="FONT: 10pt Arial">----- Original Message ----- </DIV>
<DIV style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B> <A title=vze3p5xx@verizon.net href="mailto:vze3p5xx@verizon.net">Tom Antil</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To: </B><A title=vze3p5xx@verizon.net href="mailto:vze3p5xx@verizon.net">rfi@contesting.com</A></DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> 3/2/2002 8:14:10 PM </DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> [RFI] nissan spark gap</DIV>
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<DIV><FONT face=Arial size=2>(snipped some)</FONT></DIV>
<DIV><FONT face=Arial size=2>i used a probe from back of rig&nbsp;&nbsp; and everything is radiating plug noise.(bumpers fenders frame even the bed and boltsto the antenna mount.</FONT></DIV>
<DIV><FONT face=Arial size=2>could this be a ground issue???</FONT></DIV>
<DIV><FONT face=Arial size=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; thomas antil&nbsp;&nbsp;&nbsp;&nbsp; n1xwa</FONT></DIV>
<DIV><FONT face=Arial size=2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; fitchburg ma.</FONT>&nbsp;</DIV></FONT>
<DIV>--- Cortland Richmond</DIV>
<DIV>--- <A href="mailto:ka5s@earthlink.net">ka5s@earthlink.net</A></DIV>
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