Art Unwin wrote:
"---may I go back to the "compared to a dipole" statement which Richard
keeps brushing off."

I accept a resonant dipole reference as a given.

It is true that the antenna under test and the reference dipole have
different radiation patterns. Our goal was to compare received signal
strengths at locations of interest.

The assumption was that on average, the propaqgation was nearly the same
for the signals received from both transmitting antennas. Good or bad
propagation, the difference between the signals depended on gain in the
direction of the receiver as the transmitted power was the same to both
antennas no matter where it landed.

Kraus says on page 535 of his 3rd edition of "antennas":
"Suppose that we express the gain with respect to a single lambda/2
element as the reference antenna. Let the same power P be supplied to
this antenna. Then assuming no heat losses, the current Io is the sq rt
of the power divided by the resistance of the reference antenna.

In general, the gain in field intensity of an array over a reference
antenna is given by the ratio of the field intensity from the array to
the field intensity from the reference antenna when both are supplied
with the same power P."

Kraus` example was our intended case.

Our expectations were met and our contractors were paid.

Best regards, Richard Harrison, KB5WZI