[Elecraft] PAR endz-fed

[Geoffrey Mackenzie-Kennedy]

Jim Brown wrote on Monday, March 02, 2009, at 11:09 PM:

> A few quibbles with your analysis. First, the antenna that I have 
> described is
> a simple half wave dipole, fed at a current maxima. The only tricky part 
> is
> the power rating of the choke that serves as the end insulator. My choke 
> is
> NOT a matching element, it an end insulator!

If a resonant trap is placed at the bottom end instead of a choke as an 
insulator, whose coil is the outer of a coiled length of the feeder, with 
the trap's capacitor connected to the outer of of the coax at each end of 
the coil of coax, the phase relationship between two driven vertical dipoles 
can be fine tweaked over a limited range. The scheme that you use also makes 
feeding a half-square at a top corner from the bottom practical, without a 
separate feeder going to a top corner which could distort the antenna's 
pattern.

73,
Geoff
GM4ESD