Alan Melia wrote:

[...]
The field strength is given by
                            e= (18.85*N*E*(r)^2)/X*d^3
    where N is the number of turns on the exciter coil
             E is the sig-gen voltage in mV
              r  is radius of the exciter coil; in cm
              d is the distance between the exciter coil and loop aerial in
metres
              X is the reactance of the exciter coil
        and e is in uV/metre
There is not a lot more than that in the text but I am willing to send a
photocopy to anyone who wants it.

Interestingly, Terman and Pettit also wrote "Electronics Measurements"
(McGraw-Hill 1952) and , on pp. 400-410 developed the above theme, giving more
details and sketches of various methods used in receiver measurements.Quoting
from page 403:
If the self-resonant frequency of the signal-generator loop is very high
compared with the operating frequency, so that capacitive currents are
negligible, then the field strength produced by the signal generator loop is
E = [47.15 * N * d^2 * I] / D^3
where E = equivalent electric field strength in volts per meter at center of
receiver loop,
N =number of turns in signal-generator loop,
d = diameter of signal-generator loop in meters
I = Current in signal-generator loop, in amperes,
D = distance from center of signal-generator loop to periphery of receiver loop.

unquote

I, too would be willing to supply photocopies to anyone interested

73
Andre' N4ICK