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My mate uses the 12x7 coil on his Gpx6 and I am happy enough to use the 11 coil on my Gpx6.

I believe the 11 is as good as the 12x7 on tiny stuff with the 11 extra depth on the larger.

Yet to borrow and test if the 12x7 on my Gpx6 operates any quieter than my 11 using my settings.

A nice offer Reg.

After checking my receipt and record book it appears that the lady in Maldon did not buy her QED from me, however I would be quite happy to spend some time to familiarize her with her detector. If Larry or someone else could get her name, phone number or Email address and pass it on to me I will get in touch with her and offer my services. There would be no charge.

Quote from: Doug on Friday March 15 2024 08:32:11  AEDT AM

Quote from: moodz on Thursday March 14 2024 18:31:39  AEDT PMFrom a fourier view point ( frequency domain ) all waveforms are composed of sinewaves so the discrim is easy if you can separate X from R.

Below is pic of no target /  iron /  and aluminium on a mono coil on the X sample waveform ...

No target is the middle trace so its very easy to separate ferrous from non ferrous.


https://www.geotech1.com/forums/forum/projects/differential-front-end-pi/409704-moodz-awesome-gold-pulse-induction-version-3-magpi-v3-project?p=419480#post419480

How would this work over high X ground?
doug ::419::

good question ... that is where a multichannel detector is required .. working on it.

Quote from: moodz on Thursday March 14 2024 18:31:39  AEDT PMFrom a fourier view point ( frequency domain ) all waveforms are composed of sinewaves so the discrim is easy if you can separate X from R.

Below is pic of no target /  iron /  and aluminium on a mono coil on the X sample waveform ...

No target is the middle trace so its very easy to separate ferrous from non ferrous.


https://www.geotech1.com/forums/forum/projects/differential-front-end-pi/409704-moodz-awesome-gold-pulse-induction-version-3-magpi-v3-project?p=419480#post419480

How would this work over high X ground?
doug ::419::

From a fourier view point ( frequency domain ) all waveforms are composed of sinewaves so the discrim is easy if you can separate X from R.

Below is pic of no target /  iron /  and aluminium on a mono coil on the X sample waveform ...

No target is the middle trace so its very easy to separate ferrous from non ferrous.


https://www.geotech1.com/forums/forum/projects/differential-front-end-pi/409704-moodz-awesome-gold-pulse-induction-version-3-magpi-v3-project?p=419480#post419480

Here is another triangle  wave form data.
doug ::419::

Quote from: Account Closed on Wednesday March 13 2024 22:15:49  AEDT PMI mentioned a while ago how I was watching Buy Swap & Sell Sellers attempting to quit the QED's and dropping their prices supposedly to meet the market.....what is the market?...does anyone actually buy one 2nd hand....

I feel really sorry for one particular girl at Maldon...she dropped her near New/near Unused PL2... down to $900 now from a higher starting point.....she states she has used it maximum 5 times from Brand New and "doesn't know how to use it"..just wants to be rid of it..it apparently has "all accessories" whatever that means.....how much does she have to lose to meet a market...any market......?.I can only imagine her frustration...losing money weekly in her mind as she drops her asking price..and she has a Detector she has no idea how to use....must have been a doozy presentation of 'how to use' when she bought it new........I have no idea what the New Price of the PL2 was ,so don't really know how much she has lost in real terms...with no gold to offset....

This is just one of the sellers I've seen attempting to quit them.....beyond sad.......Hoo Roo

Everyone that buys a new  QED is entitled to 1/2 day of free training with Goldman.Its inexcusable  for a customer to buy a QED and then sell it because they don't know how to use it. Maybe as  she lives at Maldon she could contact  Reg for one of his training days and at he same time learn how to drive the  QED.
doug ::419::

Quote from: Doug on Wednesday March 13 2024 22:33:58  AEDT PM

Quote from: moodz on Wednesday March 13 2024 22:29:19  AEDT PM

Quote from: Doug on Wednesday March 13 2024 21:01:58  AEDT PM

Quote from: moodz on Wednesday March 13 2024 20:20:42  AEDT PM

Quote from: Doug on Thursday March  2 2023 11:34:50  AEDT AM

Quote from: moodz on Thursday February 23 2023 11:30:20  AEDT AM

Quote from: Doug on Wednesday February 22 2023 22:43:44  AEDT PM

Quote from: moodz on Wednesday February 22 2023 22:30:22  AEDT PM

Quote from: Doug on Sunday February 19 2023 13:45:36  AEDT PMMoodz' Awesome Gold Pulse Induction Version 3 - MAGPI V3 Project?
https://www.geotech1.com/forums/forum/projects/differential-front-end-pi/409704-moodz-awesome-gold-pulse-induction-version-3-magpi-v3-project
Moodz in layman's terms could you explain what this is  all about and its pros'/cons and could it lead to the "ultimatum detector"?
doug ::419::

well in a nutshell it uses an active damping technique that allows the coil to be damped in approx a half cycle of the SRF ... which for generic mono coils is a bit over a microsecond ( my minelab mono 10inch is 1.4 microseconds ) This is much faster than a traditional damping resistor can manage. This in turn allows more amplification at an earlier point in time and because current amplifiers are used the sampling is a bit different also. Additionally there is a noise cancelling loop that gets rid of DC offsets and heavily attenuates EF earth field and mains and other noises. Not everything but much better than a standard preamp which tends to amplify everthing. It still detects hot rocks
 .. but so does the GPZ. However this relatively simple detector can detect a 0.1 gram nugget at 1 - 2 cm and a 10 cm foil target at  nearly 1 meter.... with a 10 inch coil.

moodz

Thanks! But how complex or otherwise is the circuit and is it amenable to MC?
Apart from  hot rocks how would you expect it to handle magnetic mineralized ground and earth field?
doug  ::419::

It only takes a few hours to put one together - the pcb I put up is all through hole except for one mosfet ... though JL on geotech has laid out a SMD version ... so I would class it as relatively simple. ( if you have all the parts and programmed CPU ). It seems to handle mineralised OK ... definitely works at the beach right up to the water. Its all open source and hardware so ppl can change it if they want to. There is LCD/serial and rotary control drivers in the s???????? so the controls are easy to add also. I use mine with no controls at all ... its lighter.
moodz

When you sample so early aren't you going to get a HUGE X component in the  Rx?
doug ::419::

Hmmm this is an old thread but you are exactly right there is a HUGE X component ... what I have been able to do is separate the X component from the R component ... and this is a huge step forward.

What pulse form are you using?
Why i ask is have you tried a triangle pulse and sample during the ramp up?ie sampling the step response rather than the impulse response.
doug ::419::

I have not but I know those that have and it was not successful. Do you know any patents using this method?

 No but a uxo detector has used it. Will try and find  cro or other pic.
doug ::419::

found it i think.
doug ::419::

Quote from: moodz on Wednesday March 13 2024 22:29:19  AEDT PM

Quote from: Doug on Wednesday March 13 2024 21:01:58  AEDT PM

Quote from: moodz on Wednesday March 13 2024 20:20:42  AEDT PM

Quote from: Doug on Thursday March  2 2023 11:34:50  AEDT AM

Quote from: moodz on Thursday February 23 2023 11:30:20  AEDT AM

Quote from: Doug on Wednesday February 22 2023 22:43:44  AEDT PM

Quote from: moodz on Wednesday February 22 2023 22:30:22  AEDT PM

Quote from: Doug on Sunday February 19 2023 13:45:36  AEDT PMMoodz' Awesome Gold Pulse Induction Version 3 - MAGPI V3 Project?
https://www.geotech1.com/forums/forum/projects/differential-front-end-pi/409704-moodz-awesome-gold-pulse-induction-version-3-magpi-v3-project
Moodz in layman's terms could you explain what this is  all about and its pros'/cons and could it lead to the "ultimatum detector"?
doug ::419::

well in a nutshell it uses an active damping technique that allows the coil to be damped in approx a half cycle of the SRF ... which for generic mono coils is a bit over a microsecond ( my minelab mono 10inch is 1.4 microseconds ) This is much faster than a traditional damping resistor can manage. This in turn allows more amplification at an earlier point in time and because current amplifiers are used the sampling is a bit different also. Additionally there is a noise cancelling loop that gets rid of DC offsets and heavily attenuates EF earth field and mains and other noises. Not everything but much better than a standard preamp which tends to amplify everthing. It still detects hot rocks
 .. but so does the GPZ. However this relatively simple detector can detect a 0.1 gram nugget at 1 - 2 cm and a 10 cm foil target at  nearly 1 meter.... with a 10 inch coil.

moodz

Thanks! But how complex or otherwise is the circuit and is it amenable to MC?
Apart from  hot rocks how would you expect it to handle magnetic mineralized ground and earth field?
doug  ::419::

It only takes a few hours to put one together - the pcb I put up is all through hole except for one mosfet ... though JL on geotech has laid out a SMD version ... so I would class it as relatively simple. ( if you have all the parts and programmed CPU ). It seems to handle mineralised OK ... definitely works at the beach right up to the water. Its all open source and hardware so ppl can change it if they want to. There is LCD/serial and rotary control drivers in the s???????? so the controls are easy to add also. I use mine with no controls at all ... its lighter.
moodz

When you sample so early aren't you going to get a HUGE X component in the  Rx?
doug ::419::

Hmmm this is an old thread but you are exactly right there is a HUGE X component ... what I have been able to do is separate the X component from the R component ... and this is a huge step forward.

What pulse form are you using?
Why i ask is have you tried a triangle pulse and sample during the ramp up?ie sampling the step response rather than the impulse response.
doug ::419::

I have not but I know those that have and it was not successful. Do you know any patents using this method?

No but a uxo detector has used it. Will try and find  cro or other pic.
doug ::419::