How does a manufacturer test a detector?

[bklein]

Just tried my surf pi 5” and pi pro 7-8” on the coins.
Next will try the two surf diy 1.2 boards.

Looked at the pcb’s. Pi Pro has same pcb as the DF. Surf Pi has a smaller board and TIP32C instead of IRF9640 driver.

[bklein]

I got permission to go detecting today and tested again the detectors in wet sand. I screwed up. The ring is on edge because of the way it is attached to the string. The GP Extreme and CTX still detecting it at impressive depths but the surf PI’s don’t. If I insure that the ring is horizontal it is detected by the pi’s 10-12” in sand or on top of it. I guess that agrees with the majority of reports.

[dbanner]

I suspect your idea would only work if the signal created by moving the coil in the Earth's magnetic field was always the same. However, the signal will change depending on coil orientation with the magnetic compass. Also, the Earth field elimination process removes external EMI.

Twin overlapping loops. Subtracting outputs of the two coils at front end. Then only single gate needed for timing switch.
That was the way purportedly used in the Treasure Seeker by Crone.
Supposedly cancel out ground effect and medium, long wave EMI .
No mention of Earth Field.

[6666]

Usually a PI samples at 1000 KHz, the sweep speed being 1m/s. The displacement of the coil in 1ms is 1mm, negligible enough to consider the EF signal as a DC offset within that millisecond. The same applies to EMI at 50 Hz. I'm designing a MPP mod based on this principle.

"I'm designing a MPP mod based on this principle", Thats interesting news

[Teleno]

"I'm designing a MPP mod based on this principle", Thats interesting news

Here's the thread https://www.geotech1.com/forums/show...tly-improvable

post #41 in particular describes the EF offset correction circuit.

[6666]

Thanks