grid dip AN/PRM10: Is the normal operating distance so small?
Close coupling is normal, especially when scanning frequency for resonance. Orientation is important too - in the first photo, two coils are tightly coupled. In the second photo, two coils are very loosely-coupled  If one coil was your grid-dip meter's search coil, it would give a poor dip indication.
However, once the resonant dip has been found, move the grid-dip meter's search coil further away to see the slight dip - then record the resonant frequency (this frequency will be most accurate).
Probing coils wound on closed-path ferrite material (like toroids) is difficult, and requires especially-close coupling.