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A quarter wave vertical antenna needs a path for its return current.? The high current point for a vertical is at the base of the vertical.? The return current path requires a similar high current.? With a ground radial or many radials, hopefully these are the main path for return current.? ?However, return current will still split to some degree between the radials and the outer surface of the shield of the coax feed. The quality of the radial field will determine how much return current goes into the ground radials vs the outside of the shield of the coax.? The coax will always have some level of return current on it, also known as common mode current.? A good choke balun at the coax feed point does wonders in greatly reducing the common mode current being carried on the outside of the coax.? ?A low power choke balun (>100 watt capability) can be made can be made from two FT114-43 toroids glued together (FT114-43? Fair Rite P/N 5943001001) which cost about $1.59 qty 1 or a single dual height one, also known as an FT114A (?Fair Rite P/N? 5943001201) which cost about $1.78, qty 1.? I prefer this one as it is a single toroid.? Get some friends together for even lower cost. Wind with 17 turns of RG-178B coax. You need about?36” length (($1.83/ft Pasternack) or even RG174.? Most other coaxes have tighter bend radii. Wind per the attached photo.? This should make the QMX much happier with regard to common mode code causing errant behavior.

- Steve K1RF