[TowerTalk] 4 square for 80

[Jeffrey Ach]

>From my experience, what you give up going to ¾ wave feedlines on an
elevated radio wire 4 sq is quite a bit of bandwidth.  I measure bandwidth
as the frequency excursions which result in 25% of the power hitting the
dump port.

 

My wire 4 sq for 80 (straight up vertical wires to catenaries hung from the
tower) uses 3 elevated radials for each, simple commercial current chokes
that measure pretty good Z at 80 meters.  These do not add a lot of
electrical length other than the coax, they are just beads on Teflon coax
inside.  

 

When I first installed this antenna in 1991, I used ¾ wave RG-11 buried in
the ground.  The bandwidth (see above) was no more than about 50-60 KHz.
This wasn’t’ too much of an issue on CW, but was dreadful on phone.  I
changed it to ¼ wave and strung them above ground about 3 years later, and
the bandwidth increased nearly 3x of what it was before.  

 

Jeff – W2FU