Messages

1

Information on the new developments / Re: Major discovery applicable to all SD GP and GPX series detectors.

« on: September 11, 2017, 11:25:08 pm »

Thanks for that explanation Woody.   
I don't know if you are familiar with the old Nautilus DMC-IIb.   A 14kHz VLF detector, this has settings on it for balancing the coil to the machine.  There are two controls Resistance and Capacitance (marked R and C)  - Maybe this is why even to this day it is the deepest seeking VLF I have used.

2

Information on the new developments / Re: Major discovery applicable to all SD GP and GPX series detectors.

« on: September 07, 2017, 07:01:43 am »

Would you clarify the difference between front end gain and rear LCD gain.  Thanks.

3

General Discussion / Re: Coils for modified GPX

« on: August 15, 2017, 07:06:47 am »

Hi filternozzle17,

Check the available products on the DetectorMods web page. There is an interference filter that may help.

Peter

Thanks Peter.    Just checking if the interference filter is also part of a full modification?

I see the filter is out of stock at the moment.   What is the modification that is required to the stock battery Peter?
Richard

4

General Discussion / Re: Coils for modified GPX

« on: August 11, 2017, 09:22:17 pm »

Hi filternozzle17,

Check the available products on the DetectorMods web page. There is an interference filter that may help.

Peter

Thanks Peter.    Just checking if the interference filter is also part of a full modification?

Richard

5

General Discussion / Re: Coils for modified GPX

« on: August 10, 2017, 05:30:28 pm »

I have a selection of coils built up over the last six years.   Most are DD or Anti Interference,  as I hunt in the UK for small hammered silver coins I often need to be able to discriminate iron.  I also have a small selection of monos'.
My questions are:

Will a fully modified GPX using either Coiltek/Minelab DDs or Coiltek AI coils give extra noticeable performance?   I guess the Coiltek/Minelabe mono coils will benefit but I am not sure about the DD & AI.

My biggest problem is not ground noise but EMI from suburbia/power lines/mobile phone transmitters etc. Sometimes, I cannot get a completely smooth threshold.  Will a full modification enable smooth threshold most times?

Is there an optimum coil size for a modified GPX?   I use both the 4500 & 5000.

Hello Woody, appreciate your opinion, thanks.

6

General Discussion / Re: Coils for modified GPX

« on: August 08, 2017, 07:20:02 am »

I have a selection of coils built up over the last six years.   Most are DD or Anti Interference,  as I hunt in the UK for small hammered silver coins I often need to be able to discriminate iron.  I also have a small selection of monos'.
My questions are:

Will a fully modified GPX using either Coiltek/Minelab DDs or Coiltek AI coils give extra noticeable performance?   I guess the Coiltek/Minelabe mono coils will benefit but I am not sure about the DD & AI.

My biggest problem is not ground noise but EMI from suburbia/power lines/mobile phone transmitters etc. Sometimes, I cannot get a completely smooth threshold.  Will a full modification enable smooth threshold most times?

Is there an optimum coil size for a modified GPX?   I use both the 4500 & 5000.

Any answers for this one Woody?   

7

General Discussion / Re: new mod settings on 4500

« on: August 07, 2017, 09:16:25 am »

You need the inductance to measure down into uh. Not mh.

Will this one do the job:

Modle:LC100-A
Effective display digits: 4 digits
Interface: Mini USB interface and 5.5DC Socket
Capacitance measuring range: 0.01 pF to 10uF
The minimum resolution: 0.01 pF
Inductance measuring range: 0.001 uH to 100mH
Big inductance measuring range: 0.001 mH to 100H
The minimum resolution: 0.001uH
Measurement accuracy:1 percent
LCD display mode: 1602
Test frequency range: L/C about 500KHZ Big inductance 500HZ
Size:3.15x1.97x0.82 inch
Pls reset to zero before testing
Test frequency of this item is higher, it is not suitable for measuring the electrolytic capacitor
Package include:
1x High precision L/C meter board
1x mini usb power cable

8

General Discussion / Upgrades changed away from the 3 way switch

« on: August 07, 2017, 01:42:52 am »

Around what date did the modifications for the GPX change from the 3 way switch (LSM) etc.?

9

New Detector accessories / Re: New detecting headphones now available . Designed for prospecting.

« on: August 07, 2017, 12:27:29 am »

I have impaired hearing and wear aids. The hearing of each ear is different so it is important for me and people like me to use headphones with a volume control on each cup.

Maybe you could consider this for the future.

10

General Discussion / Coils for modified GPX

« on: August 06, 2017, 11:17:50 pm »

I have a selection of coils built up over the last six years.   Most are DD or Anti Interference,  as I hunt in the UK for small hammered silver coins I often need to be able to discriminate iron.  I also have a small selection of monos'.
My questions are:

Will a fully modified GPX using either Coiltek/Minelab DDs or Coiltek AI coils give extra noticeable performance?   I guess the Coiltek/Minelabe mono coils will benefit but I am not sure about the DD & AI.

My biggest problem is not ground noise but EMI from suburbia/power lines/mobile phone transmitters etc. Sometimes, I cannot get a completely smooth threshold.  Will a full modification enable smooth threshold most times?

Is there an optimum coil size for a modified GPX?   I use both the 4500 & 5000.

11

General Discussion / Re: new mod settings on 4500

« on: August 06, 2017, 08:37:21 pm »

It is nearly impossible without testing equipment, the easiest way is to connect the coil to a variable frequency source and connect a small resistor in series with one coil wire and vary the frequency with an oscilloscope across the resistor, when resonance is achieved the signal voltage across the resistor will rise. The higher you can get the frequency the better in most cases but other effects like ringing need to be observed. Another way is to buy an automatic LCR type meter and measure the inductance, these give a Q reading, the higher the Q the better in most cases.

Would this type of LCR meter be okay to use:

UT600 series RCL meter is a kind of 3.5-bithandheld digital meter with stable performance, safety, reliability, highaccuracy and manual range.
It can be used to measure the magnification times β of audion, diode forward voltage drop and circuit continuity.
UT 603 is applicable to testingresistance, capacitance and inductance of electronic laboratory, productionline, maintenance point and teaching.
It is the ideal tool of maintaining formany users.
Specification:
Resistance (Ω): 200Ω/2KΩ/20KΩ/200KΩ/2MΩ/20MΩ Best Accuracy: ±(0.8%+1)
Capacitance (C):2nF/20nF/200nF/2uF/20uF/200uF/600uF Best Accuracy: ±(1%+5)
Inductance (H): 2mH/20mH/200mH/2H/20H Best Accuracy: ±(2%+8)
Features:
Display Count:1999
Manual Range: √
Diode: √
Transistor: √
Continuity Buzzer: √
Low Battery Indication: √

12

General Discussion / What size/weight is considered to be a small nugget ?

« on: August 05, 2017, 03:26:35 pm »

I have previously posted this on another forum but never received any reply or comment.

Minelab in their literature, when talking about coil sizes, use the expression 'small nuggets' & 'large nuggets'. I am interested to know what is the largest small nugget? and Smallest large nugget.

Being in the UK I am not detecting for gold nuggets and it would be helpful if I knew what weight/size a small and large nugget is, in order I can align them with targets found within the UK.

This information would be very helpful to GPX users in selecting soil timings/coil size and type.

13

Information on the new developments / Re: Major discovery applicable to all SD GP and GPX series detectors.

« on: August 05, 2017, 08:12:29 am »

It depends on the ground as to how to set the gain, bur as a general rule I crank up the front gain and tame the ground in the back menu gain setting. I use normal timings if the ground allows.

I understand it depends on the ground but initially where would you have the rear end gain in order to crank up the front gain?

14

Information on the new developments / What size/weight constitutes a small/large nugget?

« on: August 05, 2017, 07:01:50 am »

I have previously posted this on another forum but never received any reply or comment.

Minelab in their literature, when talking about coil sizes, use the expression 'small nuggets' & 'large nuggets'. I am interested to know what is the largest small nugget? and Smallest large nugget.

Being in the UK I am not detecting for gold nuggets and it would be helpful if I knew what weight/size a small and large nugget is, in order I can align them with targets found within the UK.

This information would be very helpful to GPX users in selecting soil timings/coil size and type.

15

Information on the new developments / Re: Major discovery applicable to all SD GP and GPX series detectors.

« on: August 05, 2017, 04:44:15 am »

Would your modifications to my GPX4500 give me any worthwhile advantage.  I hunt for hammered silver coins in the UK.  Ground is seldom highly mineralised, soil is often very damp and not very often bone dry.  Coin weight in silver from 0.6g upwards.   The land is either pasture or ploughed.

I was going to purchase a previously modified GPX4500 but it is no longer for sale so I am looking at the possibility of having the latest full upgrade done.

With you modification, based on the above, what would be the approximate setting for both front and rear gain?  And what soil timing do you believe would be best, I am assuming Normal but I may well be off track.