Here's an interesting gadget

[Carl-NC]

https://www.ebay.com/itm/273073529638

"One of only a dozen ever made! Metal detector coil test meter. Built by Electrical engineer Don Brereton of Micronair Electronics. Suitable for all IB (VLF) and PI coils, this simple 2 switch device measures the energy output of both the metal detector and coil. Swap the coil on your detector to see if if really DOES punch deeper! Digital readout provides a nominal scale of energy produced by the coil. More energy, more depth! Two switches: on/off and Hi-Lo range. Capable of measuring up to 20" coils. Super rare, you'll probably never see another again! Powered by 4XAA batteries. These were hand-built and originally cost AU$1000."

Anyone ever heard of it?

[WM6]

"you'll probably never see another again" - this could be true.

If it is "Suitable for all IB (VLF) and PI coils", then it is probably nothing more than some sort of Gauss meter.

Limited to some air measurement.

If we take Hall effect sensor attached to coax connected to Gauss meter and drop it in real hole bored in real terrain,
we can measure real energy excited at given depth in soil, not in air.

[Andi68]

I do not believe in this device.

There is a very simple way to measure the output of a VLF coil - wrap a coil of enamelled wire, d = 20cm, 20 turns and connect this coil to the oscilloscope. Simply hold this coil to the coil to be measured, so you can see the singnal on the oscilloscope.

I have not tried this on a PI coil.

[dbanner]

Looks like something left over from the Apollo moon landing.

[kt315]

More energy, more depth! -- i think the conception died after pi design born. really there is 10x Ampers in impulse.
i think energetic lamp will light in coil connected to DP but i did not still check that.

recently i found this page and it is interesting to read. i long wanted to open a 'secret' of modern 'Edison lamp'
and vu ala! http://www.superfonarik.ru/article_i...articles_id=29
it is LEDs in serial with simple current stabilizer =)))
no vacuum in the bulb.