[TowerTalk] Fwd: OT: Exterior Ethernet Cable

[HansLG at aol.com]

And I second Jim K9YC, The current that radiated is on the outside of the  
shield and that current has to come from somewhere. In most cases it comes from  
the junction point at the antenna. If you have a transmitter without proper  
shield, like the "old days" you may get it from there. 
 
High SWR can be an indication of an unbalance at the feeding point with  
current returning along the outside of the coax. A simple test is to add (or  
subtract) some of the coax between the SWR meter and the antenna. If you have a  
change in the SWR you have current on the outside of the coax.
 
Hans, N2JFS



  
____________________________________
 From: jim at audiosystemsgroup.com
To: towertalk at contesting.com
Sent:  8/12/2008 3:38:48 A.M. Eastern Daylight Time
Subj: Re: [TowerTalk] OT:  Exterior Ethernet Cable


I said:

>>SHIELDED EQUIPMENT 
>>  DOESN'T RADIATE OR RECEIVE. ANTENNAS DO!

Roger said:

>So does  feed line with high SWR.

I reply

NO!  SWR does NOT cause  feedline radiation. IMBALANCE IN THE ANTENNA 
causes common mode current on  the feedline, and that common mode 
current causes radiation.  

73,

Jim  K9YC


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