Delta Pulse

[jinbiao]

The DP I made was field tested with a 30 cm coil. The ground reaction is very strong. GB adjustment is invalid. is this normal? The test site is a laterite mineralized area with gold deposits.

[kt315]

also i think you do not set a knob of timing on your scope in fixed position. thats why you get wrong width.

[kt315]

ok. give pic of C5 i could see the value.

[Carlos]

I never saw this configuration of the CD4538 as monostable and the outputs marked with TR4 and TR5 I observe a square wave of 3uS
Carlos

[kt315]

uncorrect i think. must be approx 45us. you have to check... op lala i can't use my schematic
be cause i do not see your board to answer right.

[Carlos]

Hello everyone, a friend brought me the DP because there is no expert in electronics and I asked for help to make it work. I never saw that configuration of the CD4538 and in the outputs TR4 and TR5 I have a pulse of 3uS. is this correct?

Carlos

[jinbiao]

Dp/71 smd version is completed, the effect is very stable, there is no large coil test yet, the test distance of a copper coin is 30 cm for the current 23 cm coil.
https://youtu.be/dW9aW451dzA

[jinbiao]

xr-71.pdf
I found 5 errors and modified it.
The schematic references the kt315 version.
After the check is correct I will design the smd version of the PCB

[jinbiao]

Currently found two errors, updated and then send the schematic

[kt315]

if you draw in big CAD there is always method of the checking either schematic or pcb.

[jinbiao]

Sheet1.pdf
I plot the XR-71 schematic, check for errors. It is often difficult to check my own work.

[jinbiao]

My goal is a jar of silver dollars, 1-2 meters deep. Not a gold nugget. I think a 50cm-1m coil is the right choice.
In addition, I did George's mini pi, which is really good for gold, but without the balance function.

[kt315]

your problem you try to remake the deeper to a not deeper. deeper working with big coil. look on this pic.
this is smallest coil for a deeper. DP is NOT seeking gold nugget. small target for DP is a cola can, 1 kg meteorite, shovel,
bomb, metal mine.
DP is done for BIG CASH ON BIG DEPTH.

[jinbiao]

The 2.2k resistance is too far apart.
I think 278Ω is OK, I will continue to test this problem and make adjustments in conjunction with field tests.
thank you for your reply.

[kt315]

to reminder you that damping resistor in original schematic is 2k2?