>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
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