Minelab X-Terra coil inside. Schematic.

[Altra]

The second jpeg "X-Terra_coil3_sch.jpg " has written at the top 7.5khz?

[kt315]

mono. meaning a planar coil, ie not double D coil.

[kt315]

Did you look at Kit315's files in post number 1 of this thread?

if you open the housing of DD coil you ll see a trace of dust with water. seam of the housing is not so good clued as you are maybe waiting from greedlab the quality.
throught cracks and cabel fitting un-clued joint a water easeally spreadding into inside of coil. that gives you un-wanted sound deteriorations at moving,
especcialy in our moist climate (while not so important for Australia and US with their dry tropical climate). the water is some kinda a conductor for
static (Faraday) field you have to beware off for the stabile job of a xterra at hunting.

[kt315]

at this pic you see the trace of a water with dust, under directly the cabel fitting. ML coils are b***sh*** what I have to say to all you. this trace is at graphite cover outer layer.

[kt315]

at this pic you see a dust spreading inside housing with the water throught un-clued seam.