Scott,
The best work-up on this antenna (as many others) was done by Cebik:
http://www.cebik.com/wire/g5rv.html
The antenna is fed with open wire line - both sides are connected. Down
the open wire line a change is made to coax. Both the shield and the
center conductor of the coax must be connected.
What you read concerning decoupling the coax shield probably refers to
trying to keep RF off the outside of the coax - with a balun (not by
disconnecting the shield). The current feeding the antenna will flow on
the inside of the coax shield and the center conductor. Coax can also
conduct RF current on the outside of the shield, which can distort the
antenna's pattern as well as feed impedance. A properly made balun will
prevent this. As Ed points out, making one out of a coil of coax is
problematic. You need A LOT of turns to be an effective balun at 3.5 or
1.8 MHz - making it heavy. I would suggest forgetting the balun - as
G5RV did in his original design.
G5RVs need an antenna tuner at the shack end to be all-band.
73
Hal
N4GG
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