Another way to detect current on the outside of coax is to run your hand up and down the coax wile an analyzer is connected , if you see a fluctuation on the meter then current is following on the outside. On vhf I built sleeve chokes to remove it with great results.
If by improving conductivity, you mean flooding several acres or square miles with ocean (or saltier) sea water (or via natural intrusion near a low lying shoreline or wetlands), or installing a solid copper floor several square wavelengths in size in the parking lot, yes.
But some people have reported improved antenna performance by putting a metal mesh of ...
Below for some perspective on this topic is a NEC4.2 analysis showing the difference in performance of a 40m, 1/4-wavelength, unloaded, base-fed vertical monopole antenna system when driven against either a 5/8" OD or a 12" OD, copper-clad, 8-ft long ground rod buried in poor Earth (1 mS/m, d.c. 5).
Increasing the ground rod OD up to 12" is ...
A dipole antenna does not require a connection to an "r-f ground" reference, either in the form of a ground rod or a set of buried radials. Its radiation efficiency typically is ~95% or more without it.
OTOH, a vertical monopole does require a path to an r-f ground reference, because that path provides the 2nd terminal of the antenna system, which ...
Surely a 1m copper stake provides better ground connectivity for a vertical dipole?
What really matters is conductivity. Current doesn't just go in the ground rod and then it's done. It has to flow through the surrounding soil.
Soil isn't a very good conductor:
(68.2 kΩ, says the display)
Now imagine how much lower this resistance would be with a copper ...
The purpose of the ground radials isn’t to ground the counterpoise.
The purpose of a dense field of radials is to emulate as much as possible a perfect mirror surface, so that, to the far field, the vertical monopole seems to have a mirror image half that makes the monopole seem more like a full size vertical dipole, with a pattern maxima orthogonal to the ...
Because the radials act as ground, and they're better at it than actual ground.
Ground (as in: dirt) isn't a great conductor. A couple laid out good conductors hence work much better as ground plane than well-connected earth.
For RF, a good connection to ground potential isn't necessary – what's necessary is that there's a large plane that conducts.