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[Amps] Warm Coax question

To: <amps@contesting.com>
Subject: [Amps] Warm Coax question
From: W0YR@aol.com (W0YR@aol.com)
Date: Sat, 20 Apr 2002 07:04:26 EDT
Hi!

ANY time an electrical conductor gets warm, it is due to resistance.  You 
have a high resistance joint either in that coaxial jumper or in one or both 
of the connectors.  I'd guess it's a "cold" solder joint or joints.  
Sometimes, you can measure the thing with an ohmmeter and it will show "Ø" 
ohms, yet it will act squirrely at radio frequencies.

First replace the jumper.  If that does not stop the heating, replace the 
connectors on the other coaxes/hardlines.  If you have a contact thermometer 
you could hold it on the various parts of the joints to see where the heat is 
originating, but 99:1, it's coming from one of the joints which is faulty.

The reason the meter readings vary is because of additional resistance or 
inductance introduced into the feedline by your various hookups.  If there 
was no change in the impedance or resistance, the meter readings would not 
change.

Be sure if you use a soldering iron, that it's big enough for the job.  This 
way the solder gets melted properly.  Remember, solder is 60% lead and lead 
is a pretty high resistance metal.  That's why in high current applications, 
like plate tank coil connections silver solder is often used.

Good Luck,

Mike Lonneke
WØYR 

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