(Nov 20 2012)
AD6IW. the paint on the groundplanes of the
bottom side of the PCB is removed on the input and on
the output side.
A thin copper foil is soldered on the grround plane
on each side so it extends about 4 mm outside the board
on each side.
The copper foil is then soldered to the bottom wall of the box.
AD6IW. Input impedance and forward gain.
AD6IW. Output impedance and reverse isolation.