[BC] Re:1 5/8 foam coax

[K7qa@aol.com]

In a message dated 2/19/2007 1:25:13 PM Pacific Standard Time,  
mark3xy at gmail.com writes:

WKBW's  phasor system, which was rebuilt in
the '70s when Peter Burk was CE.   It shows 3" air line to the center
tower and 1-5/8" air to the two end  towers, but this makes sense
considering they each get half the base  current of the center.



Choosing power handling capabilities of transmission lines in an AM DA  
depends on the power delivered and returned to or from each tower base, not the  
tower base current. Much of the base current in the end towers of an inline end  
fire array is induced rather than fed from the phasor. I've built several 50 
kW  AM DA's and seen others where none of them used 3 inch line to any of the  
tower bases since the feed powers were all under 30 kW.
 
tm