GPX 4500, Ground Balance & Threshold Problem

Hi , G`day….

I`m Zoltan from Germany and I`m new here. Need some support and help how to setup my GPX machine incl. the Threshold. I purchased a new Minelab GPX 4500 Gold detector here in Germany and I hope it`s a good machine for Gold prospecting in Western Australia in the goldfields region. Some years back I went to Leonora in WA for prospecting with my old White`s 6000 DI PRO SL, but couldn`t use this VLF machine because of the high mineralization ground in WA. This machine was totally useless for me.

Later I used a GP Extreme ( old model ) from a friend with success n 2 weeks back I bought the GPX 4500 in Germany for my next trip to Western Australia.

So, even if it`s an expensive machine I think ( and I hope ) it`s a excellent machine for gold prospecting in the Outback. But I have a big problem with the setup for the Threshold cause I always have noises in my earphones and I cannot increase or reduce the Threshold sound in the background. Sound is always the same and it breaks my neck because I don`t no why  !

I don`t no how to setup to get a good n stable Threshold with less fluctuations. And I thought may somebody here can provide me a useful advice to solve the problem.

Today I went out in Germany in the forest. Stillness, no people, no power lines, interferences etc. Except my used car was approx. 50 meters away when I tried to setup the detector and the Threshold. I think the GPX machine is damn good, but I have no experience how to setup the machine to get a good result in ground balancing…and a stable Threshold. Daily I`m reading the manual….but I can`t find the solution for this problem…

Here are my last
settings…

Minelab GPX 4500
with 11" Standard Minelab Coil...

Search Mode: G ( General )
Soil Timings: N ( Normal )
Ground Balance: Fixed
Coil / RX : Double D or Mono

1st: I turn on the machine and increase my
Threshold button usually between 10" and
2" o`clock.

2nd step: I push Auto Tune and waiting for
three beeps after 1 Minute ( appr. ) for the
best frequencies results.

3rd: I push the green Quick Track button,
hold the button and I`m pumping the coil
slowly up and down, than a bit slower and
last but not least I hold the coil still before
I release the green button.

As follows my
setup:

MAIN MENU:

Volume Limit: 12
GB Type: Specific
Special: Sens Extra ( FP )
General: Motion = Slow
RX Gain: 8 ( FP )
Audio: Normal ( FP )
Audio Tone: 50 ( FP )
Stabilizer: 10 ( FP )
Signal ( Peak ): Between 16 and 19
Target Volume: 8 ( FP )
Response: Normal
Tracking: Medium ( FP )
Iron Reject: Off


What could be the problem..? I become
headache because of the Threshold and
mostly I can not increase or reduce the
sound. I think it`s not a big problem to
solve.

I think the Gain ( 8, FP ) is not to high
cause usually here in Germany we don`t
have problems with high mineralization
ground and may some experienced GPX
4500 prospectors could help to solve this
problem…

Sorry for my bad
english…

Best Regards
Zoltan

G'day Zoltan

Welcome to the forum, and I hope I can help you.

Firstly reading through your settings I notice you have the "GB Type: Specific" in your menu settings, change this to "GB Type: General" which is the FP setting.

Once you get better at using you new machine you may then work out how to use the "Specific" setting, as it is a bit tricky to use when not familar with the machine.

Also with the threshold knob just turn it anticlock wise until there is no sound at all, then turn it slowly clockwise until there is a steady hum. Usually the dial is pointing at the autotune button at this stage, or about 12'Oclock position.

Your ground balancing method procdure sounds about right.

Hope this is of some help.

cheers dave

Also, try and get hold of a Nuggetfinder or Coiltek Mono coil as the 4500 is best suited to these coils in WA.
Minelab Commander coils are also good but are considerably heavier.

Robert

Goldnomad wrote:Also, try and get hold of a Nuggetfinder or Coiltek Mono coil as the 4500 is best suited to these coils in WA.
Minelab Commander coils are also good but are considerably heavier.

Robert

Hello Robert ;

Thanks for your message and for your suggestions. First time when I came to Leonora ( WA ) in 2005 I saw a lot of gold nugget hunter with Coiltek spider UFO and Mini UFO coils ( all Mono ). Even I prefer coiltek coils. But the Nuggetfinder coils must be also v. good for WA.

Regards
Zoltan

davsgold wrote:G'day Zoltan

Welcome to the forum, and I hope I can help you.

Firstly reading through your settings I notice you have the "GB Type: Specific" in your menu settings, change this to "GB Type: General" which is the FP setting.

Once you get better at using you new machine you may then work out how to use the "Specific" setting, as it is a bit tricky to use when not familar with the machine.

Also with the threshold knob just turn it anticlock wise until there is no sound at all, then turn it slowly clockwise until there is a steady hum. Usually the dial is pointing at the autotune button at this stage, or about 12'Oclock position.

Your ground balancing method procdure sounds about right.

Hope this is of some help.

cheers dave

Hello Dave ;

Your description is very helpful. Thank you. Now I`m thinking that my problem is because " Specific " in my menu settings. Even Jonathan Porter found the same problem in my settings. Even JP suggested me not using Specific, better change to GB-Type " General ". Now I think is also bit easyer for me to understand the Threshold and how to use. First I should turn anticlockwise until there is no sound at all and than slowly and clockwise til I can hear a steady hum. Right ? Well I will do that the next time. Is not very difficult to understand the GPX 4500 machine, but yesterday I went out with my machine the 1st time and I didn`t understood how the Threshold controller is working and how to adjust the controller.

Your description helps me a lot.
Thank you...

Best Regards
Zoltan

hi i am sure this is not your problem but just to check off

once i forgot to plug my quicktrack button into the machine makes it real hard to GB then

flying kiwi wrote:hi i am sure this is not your problem but just to check off

once i forgot to plug my quicktrack button into the machine makes it real hard to GB then

Hi Flying Kiwi
Thanks for your message.

I`m not sure but I don`t think that`s a wire problem cause the wire from the Quick Track Button was connected with my machine and before I started using my machine I didn`t understood how to adjust the Threshold button.

Later I tried " Specific " Ground balance settings ( I selected in Menu ) and after I switched to Specific for a new Ground balance I was not able to work with the machine. The Results: Permanent faulty signals, signals, signals whenever I swepped the coil over the ground.

But may is also my own mistake because I didn`t understood for what is the Threshold and whenever I switched my machine on, first of all I increased the Threshold button usually between 10" and 2" o`clock, no matter what about the Threshold sound in the background, because It was always loud enough . Now I know It is one of the most important settings and should be my ear in the ground

It should be smooth, still audible,
but not to loud.

When I came to WA the first time I had a mate for my GP Extreme machine setup in the bush. May thats the reason why I`m not so familiar with the Threshold controller. Otherwise is not very difficult to understand the machine. I guess.

HOPE MY ENGLISH IS NOT A CATASTROPHE.
My 2nd Problem... LOL....

Warm Regards
Zoltan

Hi Zoltan
These machines are very user friendly,you can always return to factory default and run through the standard setup.Not sure off how you ended up in specific but it sounds like the machine was way off ground balanced,normal GB and fixed tracking should sort it out.Your settings sound fine.
Steve

deutran wrote:Hi Zoltan
These machines are very user friendly,you can always return to factory default and run through the standard setup.Not sure off how you ended up in specific but it sounds like the machine was way off ground balanced,normal GB and fixed tracking should sort it out.Your settings sound fine.
Steve

Hi Steve ;

Yes, absolutely. The GPX 4500 is really user friendly and additionally I have the manual in german language as well. Not really necessary cause I can read the manual in english too. But german n hungarian language is my mother tongue, I speak both languages fluent and than is little bit easyer for me to read the instruction manual in german version.

First when I tried to do the ground balance I selected GB Normal mode and fixed tracking. Than the GB was o.k., except the Threshold because It was always to loud, stuttering and not smooth. After this problem I switched from GB normal mode to Specific and I tried a new Ground balance. But than the problem started. I was not able to work with the machine. Well, In the future Steve better I`m using normal GB, fixed tracking and not Specific.

Best Regards
Zoltan

Morning Zoltan,
A tried and proven combination with the 4500 is to use the Round 11" Minelab mono.
You mention threshold in most of your posts, once you have it set to your comfortable level forget it. You may need to increase if wind speed picks up.
If you concentrate on gain/stabilise settings this machine runs very smooth.
I see you have stabiliser set higher than your gain? This is unusual.
Get your manual out and study that section.
Running in "enhance" the machine is usually very stable.
If you continue to have instability, try switching the FP to "special" and "sensitive smooth"
Here are one list of settings we use in Leonora area. We use external speakers.


GPX-4500
Front Panel
Search mode = General
Timings = Enhance
Ground balance = Fixed
Coil RX = Mono
Rear Digital
Back Light = Off
Battery Test = 8+
Volume Limit = 10
GB Type = General
Special Smooth (Only when front timing is set to “Special”)
Manual Tune = 95
Motion = Slow
RX Gain = 10/12
Audio = normal
Tone = 50 (your choice, practice with a small target and set this option to your hearing. Rule of thumb, the older you are the lower the tone)
Stabiliser = 8
Signal = 10
Target Volume = 10
Response = Normal
Tracking = Medium
Iron Reject = Off (This function only operates with DD coils)

Nightjar wrote:Morning Zoltan,
A tried and proven combination with the 4500 is to use the Round 11" Minelab mono.
You mention threshold in most of your posts, once you have it set to your comfortable level forget it. You may need to increase if wind speed picks up.
If you concentrate on gain/stabilise settings this machine runs very smooth.
I see you have stabiliser set higher than your gain? This is unusual.
Get your manual out and study that section.
Running in "enhance" the machine is usually very stable.
If you continue to have instability, try switching the FP to "special" and "sensitive smooth"
Here are one list of settings we use in Leonora area. We use external speakers.


GPX-4500
Front Panel
Search mode = General
Timings = Enhance
Ground balance = Fixed
Coil RX = Mono
Rear Digital
Back Light = Off
Battery Test = 8+
Volume Limit = 10
GB Type = General
Special Smooth (Only when front timing is set to “Special”)
Manual Tune = 95
Motion = Slow
RX Gain = 10/12
Audio = normal
Tone = 50 (your choice, practice with a small target and set this option to your hearing. Rule of thumb, the older you are the lower the tone)
Stabiliser = 8
Signal = 10
Target Volume = 10
Response = Normal
Tracking = Medium
Iron Reject = Off (This function only operates with DD coils)

Hello Nightjar ;

Thanks very much for your message and for your setting informations. So, do you mean the stabilizer should be usually lower than the gain ? I didn`t no. Really. But it`s really good to know cause my GPX 4500 machine is new and I didn`t understood the Gain and the Stabilizer when I`m using the machine. I think when we can increase the Gain ( depends on the ground ) than usually we can get a better depth. But I don`t no how to use the stabilizer ( Gain & Stabilizer Settings ) to get a stable Threshold and a smooth running GPX 4500 machine.

So, when I`m doing the ground balance, what would you suggest me ? I mean should I switch to enhance mode ( front panel ) before I push the green Quick Track button for Ground balancing or should I switch later to enhance after I finished the ground balancing ?

I think the Standard GPX 4500 11" Coil is a Double D coil. Can I use the same coil also in Mono when I switch from DD to Mono ( front panel ) ?

This Forum is really nice, very helpful, nice and experienced people and I`m really happy to be here.


Bet Regards
Zoltan

Yes Zoltan,
You can use the supplied DD coil and switch to mono however remember only one half of the DD coil is active in mono. It would be advantageous if you purchased a mono coil.
Set all your switches and digital settings, and do a ground balance, the Gain & Stabiliser adjusted last of all. (This is all explained in the manual)
Holding the coil just above the ground, increase your gain until the machine becomes slighty unstable then back it off a fraction, now increase your stabiliser until this also becomes unstable and once again back it off until stable.
You are ready to start swinging. It is is advisable to ground balance often to keep the machine stable.
Once you become more familiar with the machine use the manual tuning as opposed to the auto tune, slowly range the settings between 95 & 110 for best results.

All the best
Peter

Nightjar wrote:Yes Zoltan,
You can use the supplied DD coil and switch to mono however remember only one half of the DD coil is active in mono. It would be advantageous if you purchased a mono coil.
Set all your switches and digital settings, and do a ground balance, the Gain & Stabiliser adjusted last of all. (This is all explained in the manual)
Holding the coil just above the ground, increase your gain until the machine becomes slighty unstable then back it off a fraction, now increase your stabiliser until this also becomes unstable and once again back it off until stable.
You are ready to start swinging. It is is advisable to ground balance often to keep the machine stable.
Once you become more familiar with the machine use the manual tuning as opposed to the auto tune, slowly range the settings between 95 & 110 for best results.

All the best
Peter

Thanks a lot Peter ! I will go out in the field tomorrow afternoon and will try again for better results. Oh, before I forget: Should I setup the Gain and the Stabilizer " after I release the green Quick Track button " for ground balancing or is it necessary to hold the Green Quick Track button when I setup the Gain and the Stabilizer and than releasing the button? Otherwise your description is v. helpful for me.

Thanks Peter.

ps: Zoltan

Hello Zoltan,
Do not use the button when setting gain and stabiliser.
Read your user handbook carefully and then take it with you for reference, then read it again.
Hope to hear soon that you are beginning to master your machine.
I can't comment on the 5000 (don't own one) however I do know the GPX-4500 is by far the most superior machine for use on mineralised goldfields to find sub gram nuggets out of reach from previous detectors, it may also prove to be a treasure hunter as well? Be prepared to dig deep holes.
Good luck
Peter

Nightjar wrote:Hello Zoltan,
Do not use the button when setting gain and stabiliser.
Read your user handbook carefully and then take it with you for reference, then read it again.
Hope to hear soon that you are beginning to master your machine.
I can't comment on the 5000 (don't own one) however I do know the GPX-4500 is by far the most superior machine for use on mineralised goldfields to find sub gram nuggets out of reach from previous detectors, it may also prove to be a treasure hunter as well? Be prepared to dig deep holes.
Good luck
Peter

Hello Peter ;

Now for me is better to understand the Gain and Stabilizer function. Thanks. The new GPX 4500 is an expensive machine, but otherwise what is a cheap VLF detector worth, especially in the goldfields and in high mineralization ground in WA. I made a mistake in the pastence because some years back I purchased a White`s 6000 DI Pro Sl metal detector, but I couldn`t use the machine in Leonora / WA. It was a nightmare. Usually the machine is not bad, not pulse induction, a traditional VLF detector, but is preferred to use in Europe or may in Canada, without to much of high mineralization ground. so, I don`t want to do the same mistake in the future and it is the reason why I decided buying a new minelab GPX 4500 machine, Made in Australia. I believe in Minelab`s technology.

Best Regards
Zoltan ( Germany )