Tuning a large loop to resonance and measuring the loop inductance is easy
without any instruments but a receiver and a calculator.
Just couple to the loop with a toroid and put a silver mica bank of
capacitors in series with the loop. Feed a receiver and tune for peak in
the noise. Once you find a noise peak the standard resonance formula with
the known capacitance will tell you the inductance of the loop. To check
it out, and what I did here, was to setup a resonance on 138.83 and another
on 135.922. The mathematics works very precisely down to less than 30 pf
ambiguity, in my case just about half a kHz. The difference is a small
plug in bunch of small value silver mica capacitors.
I did not originate this, Bill, VE2IQ did many years ago.