Hi LF group,

I have managed to acquire a few very large ferrite rods (36 cm x 10 cm
x 2 cm). The material is unknown but I managed to form a square
'toroid' with four of them (they are heavy so gravity was enough to
keep everything in place for a measurement) and I measured about 15 uH
for 4 turns at 0.1 MHz, which if I have done the calculations
correctly implies a relative permeability of about 1000.

The R of the impedance of the square loop was low (<0.2 ohm) at 0.1
MHz and it increased fast with frequency (170 ohm at 5 MHz!).

The question is, what LF/VLF experiment would you do if you had half a
dozen of these rods?

73, Dimitris VK2COW