I adjusted the transmitter for 2A aerial current flowing into the
strapped feeder wires.
Current in the connection from the coil to the central heating
radiator was then 2.1A.
If this difference is explained by an in-phase (radiation) and quadrature
(capacitive shunt from coil strays to ground) current, then it has the
following vector constitution:
2.0 + j0.64 = (modulus) 2.1 amps.
Until phase data is confirmed, the "difference current" can range from 0.1
to 0.64 amps, as RF ammeters indicate the net (modulus) current and "don't know"
about vector components.