Very strange effect … - Fisher Gold Bug pro

[Riss]

I repaired a probe (5" ) for Fisher Gold Bug pro - operating frequency of 19 kilohertz. As I expected, it reacts to the palm of my hand on both sides. It also reacts to my hand - before the wrist. However! – I bring my collected outstretched fingers closer to the probe – no reaction! there is no logic... maybe because there is less blood in the fingers?

[Carl-NC]

It's body salt. The palms have more padding (flesh), fingers are more bone.

[Riss]

It's body salt. The palms have more padding (flesh), fingers are more bone.

Thanks for the reply, Karl

[ivconic]

It's body salt. The palms have more padding (flesh), fingers are more bone.

It's true.
I found that the detector has a longer range and better detection through the human (or any living) body than through air.
When covid started, those days I finished the first copy of Pulse Star II.
A veterinarian contacted me and asked me for a detector with which to examine the cows.
Because cows chew, roll up and swallow various wires, needles, barbed wires... because they don't feel pain in their mouths and tongues.
Such metal ends up in the rumen, sooner or later pierces the wall of the rumen and goes to the hearth direction, pierces the heart and causes inflammation
from which the cow dies after ten days. The "wall" of meat from the side to the heart is often more than 30 cm in adult cows.
He brought samples of various metals taken out of cows for us to test various detectors on.
Neither successfully detected those pieces of metal at the distances required. Not even the Deus.
And then I remembered the Pulse Star II detector and the little "room" coil I made to serve me just for room tests while I handle the detectors on the workbench.
The coil was less than 19cm in diameter.
Pulse Star II is the first and only detector that successfully detected all offered metals at decent distances in the air.
But even better "through the flesh". 20-30% better.
And that made the vet decide to buy that work from me. He still uses it to this day. He brought it the other day just to change the battery.
I remember that we tried it by placing the metal on the inner side of the thigh, between the legs, and using a probe to detect the metal on the other side of the leg.
The detection was "enhanced" clearer and better than just in the air. I wondered then why that was.
Precisely because of the liquid and salt.

[Skippy]

Plenty of salty water in your body. Not much iron / iron 'oxides' in blood, despite its 'rusty' red colour.

[kt315]

Plenty of salty water in your body. Not much iron / iron 'oxides' in blood, despite its 'rusty' red colour.

sorry, not. I bring my collected outstretched fingers closer to the probe it's clear for me Electrostatic Field Influence (ESFI) works. he MOVES the probe.
he must bring it to fingers (either fingers to probe), NOT MOVE THE PROBE AND FINGERS, STATIC POSITION, and TURN ON the detector.just then it will be clear test.

[Altair]

I repaired a probe (5" ) for Fisher Gold Bug pro - operating frequency of 19 kilohertz. As I expected, it reacts to the palm of my hand on both sides. It also reacts to my hand - before the wrist. However! – I bring my collected outstretched fingers closer to the probe – no reaction! there is no logic... maybe because there is less blood in the fingers?

Sorry but I don't understand: if the detector reacts to the hand near coil should be to a capacitive effect, but I suppose the Fisher coil have a shield so it does not happen...?? Otherwise there are detection of salt inside the hand and this would be very interesting.
Different case is what say Ivconic; in this case seems that eddy current are formed inside the flesh and that influence the detection of a metallic target positioned beyond the flesh; I am wonder why...

[kt315]

but I suppose the Fisher coil have a shield so it does not happen...??

did you see the probe opened? not. did you see fat graphite layers on both covers? not. did you check a connection from both shields to GND wire? not.
just your bare naked guess.

Otherwise there are detection of salt inside the hand and this would be very interesting.

OMG

[Skippy]

Quote: "Sorry, not"
Try this experiment:
make a 'glove' from a black anti-static bag, connect this with a thin wire to the detector ground. Then insert your hand, and try waving it over the search coil.
I tried this ( on a Fisher F75 ) and it made no difference, the hand was still detected, as an iron tone.
Now the GoldBugPro is slightly lower down the 'hierarchy' than the F75 / T2, but not much lower, so I would expect the GBP to have decent shielding, and not give any response electrostatically. One possible reason for static pickup could be the 5" / 125cm coil. My experiment was done with the 11" x 7" bi-axial coil.
Unfortunately I am way too busy at the moment to do any further experiments on this topic.

[Altair]

Otherwise there are detection of salt inside the hand and this would be very interesting.

OMG[/QUOTE]

Salt is sodio clorure; sodio is a metal.

[Carl-NC]

Body salt effect is real. I am seeing it now on a PI circuit I am working on. If I take the delay down to 2-3us I can detect my hand at 15cm. If the delay is turned up to 5-6us, I cannot detect my hand at all. This shows it is most likely an eddy-conductivity issue. Shielding makes no difference with this, and I am using a well-shielded coil.

[kt315]

I am seeing it now on a PI circuit I am working on. If I take the delay down to 2-3us

Fisher Gold Bug pro is VLF, not PI. they are done in China. poor shielding of the coil, or break of connection shield - GND wire, or absent of the shield.
chineses do poor things... this is normal. if they can do something without something - they will do without doubt shadow.
if they can change Cu on Al in a thing - they will change.
if they can change Al on plastic - they will do always. Without doubt shadow.
they pack chip of LM358 and marked as TL072 - this is very normal for chineses. be cause 'works? then buy'.
I got DP board back from buyer, to find problem. his LF357 inserted in the pcb did not give a signal on output. just an example.
chineses do the fakes and sell them - this is normal business.

[Carl-NC]

I am unaware that China has counterfeited the 5" coil, so I am sure it was made in El Paso, Texas, not China. The shielding is quite good. Body salt can also be detected with a VLF. The higher the frequency, the easier it is to detect.

[kt315]

then what is it?

[Skippy]

FISHER RESEACH LABS .... cannot even copy the name correctly ( yeah I know: I couldn't copy a Chinese character properly , but ... )