Field Day 2015

[N1GNV]

Hmmm... I'm not sure I agree with all of (or maybe I just don't understand)

"Once the current and voltage are pushed either up the stub or down the coax, due to the wide departure from the design frequency, cancellation does not occur. Hence the stub and feedline radiate"

My understanding is that if the antenna is balanced with respect to ground -- and I think we can assume ours is, or very close to it -- then the currents are equal in magnitude (voltage) but 180 degrees out of phase. That should hold true even if the load (antenna) has some reactive component, no? Then down the ladder line, that balance should hold true and being 180 degrees out of phase, the signals cancel -- ergo, no radiation from the feedline DOWN TO THE POINT OF TRANSITION TO COAX.

Then, of course, the feedline (because it's coax) becomes unbalanced with respect to ground, so some current flows down the outside of the braid and VOILA! we have feedline radiation from the coax. So maybe the first line of defense is a good quality low-loss balun between the coax and ladder line?

73, John Bee N1GNV

John and others,
Background, late 1940's early 1950's:
The G5RV was designed by Varney as a 1.5 wavelength radiator for the 20 meter band, hence the 34' matching section to provide a resistive load on the 20 METERS.