Monday, July 5, 2010

Lesson 25: Technician Class Exam Prep T7C

Hello!  Here is lesson 25 covering the T7C questions dealing with antenna measurements and troubleshooting.  This is a fairly simple lesson.  The two main topics deal with Standing Wave Ratio (SWR) and not to let moisture into your coaxial cable.  Generally speaking, SWR measures how well a signal from a transmitter is matched to a transmission line.  An SWR meter will provide you with a ratio of how much of the signal you're trying to transmit is being reflected back at the transmitter through the feedline.  A 1:1 ratio is perfect.  Unfortunately, a 1:1 is a little impossible to get.  However, you can come very close.  A high SWR may not only mean that your signal is doing nothing but heating your feedline, but the reflected power could potentially damage you equipment.  I found a nice and basic overview of coaxial cable and SWR which you can find the link to in the Ham Links box.

Until next time...

73,
Andy
KE4GKP


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