My MPP vers E completed but not finished ... yet

[godigit1]

Now that i see the attachment i see you are allready there. My bad.
Looks good.

[6666]

Thanks 6666. Invalid for me too now. I've posted the pic again.

[ATTACH]46107[/ATTACH]

Thanks got it now

[Polymer]

I am getting "Invalid Attachment"

Thanks 6666. Invalid for me too now. I've posted the pic again.

[6666]

I am getting "Invalid Attachment"

[godigit1]

Ps do the TX mods if you havent yet that way you can really change thing up.

[godigit1]

Question:
What would moving the second sample window further to the left do as to detection behaviour?
I have not started looking at how to do this as I hate fudging around in what is a well working circuit for me.

In the KrinAZ mods adding the trim pots to r 23 and r35 would be the rev e you can play with it. the sample widths are still in sink though if you want to change that its a little more work you have to cut a trace and add a pot and i think change the integrator. I used a 5 k at r 35 and a 50k at r34.

[waltr]

The the left meaning a shorter second delay---
If you get the coil over a target with a long TC, silver, then the target's decay can extend into this second sample.
This could decrease the sensitivity to long TC targets.

[Polymer]

I am enjoying the MPP vers E with various mods, especially from KRinAZ.

I find the build instructions great and the way the 555 timer has been implemented for making the variable pulsing signals
with the pots is one nifty little circuit. -Lift hat and bow- ... George and ALL thank you!

I have some questions -hell, of course I do-

Here's a composite of all my signals with timing:


Question:
What would moving the second sample window further to the left do as to detection behaviour?
I have not started looking at how to do this as I hate fudging around in what is a well working circuit for me.

The EFE is working fine, whipping the detector around in all directions gives no signal.
Power used is 70mA @ round 1800Hz @ 39uS pulse width, oval coil, shielded, nickel @ 10-12", real in situ testing.

The spikes/dips on the decay curve after opamp are from the LT1054.
The are an irritation, but can tune them out with frequency change.
Have yet to look why and find remedy.

Also would like to build a ferrite PP for this one.

This project is completed but not finished yet ... oxymorons abound ...