Threshold Pot doesn't work

[Carl-NC]

Sorry for my questions.
As you know, we use foil over coil with a gap.
Do you think we still need the gap with copper-nickel plating?
And, should i connect the plate with a wire to ground?
Thanks

Yes, you should always use a gap, even with a painted shield. Yes, connect the shield to the "ground" side of the coil.

[h9361]

Hello
Dear Carl
I hope you are passing good days.
If you remember, you helped me to add a VU meter over my HHd (attached).
As you know, most of VU meter is ranged 300 or 500 uV.
I have a problem with it. As soon as receiving signal, the needle of meter always goes to endpoint.
I think voltage range of signal is much bigger than 300 or 500uV.
My question is, do you have any suggestion to convert output signal to 300 or 500 uV range?
Thanks

[Carl-NC]

Increase the value of R36 (the one that drives the meter) until it does what you want. You might also need a resistor in parallel with the meter, I would start with 10k.

[h9361]

Increase the value of R36 (the one that drives the meter) until it does what you want. You might also need a resistor in parallel with the meter, I would start with 10k.

Thanks dear Carl.
Please see attached, do you think position of the 10K is correct?

[Carl-NC]

No, across the meter terminals, not in series.

[h9361]

I think your means is that, is it correct?

[kt315]

I think your means is that, is it correct?

[ATTACH]58198[/ATTACH]

look Delta Pulse VU meter resistor connected. a 'snow' sign is meant 'tuned value'.

[Carl-NC]

Correct.

[h9361]

Thanks dear Carl and Kt315.

[h9361]

Hello
Dear Walter
I have a question about your experience with concentric/DD coil.
Can you tell me what type cable you used between coil and unit? For exp, Microphone ?!

[waltr]

Hello
Dear Walter
I have a question about your experience with concentric/DD coil.
Can you tell me what type cable you used between coil and unit? For exp, Microphone ?!

For my PI detector I use CAT5E cable.

[h9361]

Hello
Dear Walter
Please forgive me for my questions.
Can you tell me your battery amperage and maximum hour that you had experienced?
As you know, HHD consuming is approximately 100mA.
I'm going to series three 3.7V-2200mA batteries, but i can't estimate its maximum hour for continuous working.

[waltr]

I use 3S LiPo with 1200 to 1800mA-Hr capacity.

Is that 2200mAmp-Hour capacity? If so then simply divide that by average current draw.
2200/100 = 22 hours but divide in half to be safe for the Li (they die if over discharged) so easily 11 hours of operation.

[h9361]

Hello
Dear Walter
As you know, i have built a concentric coil.
Today, i tried to add a shield (graphite or foil) to both inner and outer coil but i had a problem.
As soon as connecting shield to ground (+B), my TP4 will be broken.
This is TP4 without shield


And this is with shield connection

Do you think it's normal for concentric coil?
Thank you.

[waltr]

Pictures of how the shield is done.
Is there a gap to prevent eddy current within the shield?
Did you try re-nulling the coils with the shield?