Can the Minelab CTX be run with negative GB? Perhaps.

Your local armchair detectorist reporting here. LoL

The CTX model, I used this morning a while before getting rained out.

Most folks who transitioned from explorers and Etrac, maybe they just turned on selected their pattern and started hunting.
I mean the ground balance system really is a no brainer right?

Well, it seems not all processes talking about low trash, high trash, ferrous coin, and ground Coin.
One of these processes not created equal it seems when it comes to ground balance.

The ground coin process is the standout.
Now, the manual for CTX recommends this process for hunting higher mineral soil.
Wonder why they recommend?

I contend the GB setting when using auto GB is set negative using Ground coin process.
I don't think the manual alludes to this.

Why do I suspect this?

My experiment.
With manual 25 sensitivity or auto plus 3 running at 26 this morning.
6" coil used.

With a blank screen selected, using ground coin continuous feedback on my ground,,like low tones for nails.
Select ferrous coin, all other settings the same, detector quiet.
Select high trash, the same quiet.
Select low trash, the same quiet.

So ground coin is noisy.
So what about a manual GB here when done?
I did just that.
Then ground coin is quiet like the rest.

Also, just lowering coil to the ground, this can be seen, and changing process setting.
Remember your mileage may vary due to soil mineral levels.

More data.
I did a few comparisons this morning over yep" those buried for around 25 years zinc washers".
I compared ground coin and ferrous coin (no manual GB set)
What did I notice different?
Ground coin gives more accurate and faster conductive number ID vs ferrous coin.
Also ferrous coin cursor pic was more ragged.
Remember this is a washer, not a coin per SE.

So were the differences noted caused by this I suspect negative GB with ferrous coin or some thing else involved with the process of either ground coin or ferrous coin processes?

Local armchair detectorist Out.



Edited 1 time(s). Last edit at 08/28/2017 05:58PM by Sod-buster.

What any mode does on the CTX is make targets stand out.
The computer is told to alter the preference towards the "prefered" signal.

In mineralised ground your first response when you up the sensitivity is a ferous signal using tracking.

They provided a fixed ground balance to enable the CTX to hunt plowed land with varying air gaps under the coil.
You ground balance with minimal air gap and start hunting. That way the CTX isn't constantly adjusting its ground balance and has a smoother feel to it.

I can't understand why you would want a CTX to run negative ground balance. It has just about the best ground tracking available for a multi frequency VLF
and just about the best ID for a multi frequency VLF. There are deeper units which you should be aware off.

Deepest mode on the CTX is pinpoint, it is an awfull pain to work with, but it will aquire targets beyond the reach of the disc channels.

But then again if depth is your number one priority, there are other machines which hunt deep and hunt with minimal effort.

With Minelab it's easy to understand, price goes up, depth goes down.
When target signal is nearly lost in the ground signal because of depth, their units become gold-machines. A simply target aquired, dig a hole machine.

HH
Johnb

scoopjohnb Wrote:
-------------------------------------------------------
> What any mode does on the CTX is make targets stan
> d out.
> The computer is told to alter the preference towar
> ds the "prefered" signal.
>
> In mineralised ground your first response when you
> up the sensitivity is a ferous signal using tracki
> ng.
>
> They provided a fixed ground balance to enable the
> CTX to hunt plowed land with varying air gaps unde
> r the coil.
> You ground balance with minimal air gap and start
> hunting. That way the CTX isn't constantly adjusti
> ng its ground balance and has a smoother feel to i
> t.
>
> I can't understand why you would want a CTX to run
> negative ground balance. It has just about the bes
> t ground tracking available for a multi frequency
> VLF
> and just about the best ID for a multi frequency V
> LF. There are deeper units which you should be awa
> re off.
>
> Deepest mode on the CTX is pinpoint, it is an awfu
> ll pain to work with, but it will aquire targets b
> eyond the reach of the disc channels.
>
> But then again if depth is your number one priorit
> y, there are other machines which hunt deep and hu
> nt with minimal effort.
>
> With Minelab it's easy to understand, price goes u
> p, depth goes down.
> When target signal is nearly lost in the ground si
> gnal because of depth, their units become gold-mac
> hines. A simply target aquired, dig a hole machine
> .


I am not dogging CTX here.
Just pointing out GB is different using auto GB between ground coin vs ferrous coin, high trash, and low trash processes.

And folks looking to run open screen combined mode,,,using ground coin may be troublesome.
And soil minerals levels depending on how high may affect.

Wish I had Etrac, would like to compare ground feedback when difficult ground is selected vs Not.



Edited 2 time(s). Last edit at 08/29/2017 12:22AM by Sod-buster.

VLF 101
Shifting ground balance from optimum point alters ID.

In order for the FBS2 unit to achieve a consisive ID in different ground it needs ground balance to be exact every time.

If ferrous or mineral shifts ID on the conductive/ferrous spectrum, you can alter signal processing to achieve the optimum ID "The ID people are use to"
If rapidly or slowly changing ground alters ID you need your GB to follow rapidly or slowly for optimum depth.

So no. CTX doesn't have positive or negative ground balance. It has optimum ground balance all the time.
How fast it changes it ground balance, how it processes the signal, how it displays the TID and audio, they all change.

To understand this you need to get hold of an X-terra 705 and hunt with manually pumping the coil for GB.
It can display GB point, it can display GB level, audio and TID span near the entire 360° of conductivity spectrum.
This unit will teach you an awfull lot about the ground your hunting.

The XP range of detectors will keep you guessing about GB point and level.

HH
Johnb

Didnt know you could hunt in PP? I assumed it would track and loose depth rather quickly. I dont believe the CTX has the ability that say a whites does to set the GB at negative which mostly was used for raw gold hunting i believe.

It doesn't track, that's the beauty and the problem of the PP.

Beauty is depth, problem is you need to re-PP every few yards.

It hits PI depth on beaches that way, often the only way to hunt on a sanded in beach with the CTX.

Anyway, targets the CTX has a problem with in disc. The SDC will clearly identify even with it's small coil :-)

That's why I've sold the CTX, still have the Excal, X-terra and the SDC. And the MXT because it just plain hunts.

HH
Johnb

scoopjohnb Wrote:
-------------------------------------------------------
> VLF 101
> Shifting ground balance from optimum point alters
> ID.
>
> In order for the FBS2 unit to achieve a consisive
> ID in different ground it needs ground balance to
> be exact every time.
>
> If ferrous or mineral shifts ID on the conductive/
> ferrous spectrum, you can alter signal processing
> to achieve the optimum ID "The ID people are use t
> o"
> If rapidly or slowly changing ground alters ID you
> need your GB to follow rapidly or slowly for optim
> um depth.
>
> So no. CTX doesn't have positive or negative groun
> d balance. It has optimum ground balance all the t
> ime.
> How fast it changes it ground balance, how it proc
> esses the signal, how it displays the TID and audi
> o, they all change.
>
> To understand this you need to get hold of an X-te
> rra 705 and hunt with manually pumping the coil fo
> r GB.
> It can display GB point, it can display GB level,
> audio and TID span near the entire 360° of conduct
> ivity spectrum.
> This unit will teach you an awfull lot about the g
> round your hunting.
>
> The XP range of detectors will keep you guessing a
> bout GB point and level.

Vlf 101 tells me, unless some thing is wrong with my CTX,,that ground coin is using an offset of some sorts ground balance wise vs the rest of the processes.
Now, maybe Minelab considers this optimum, but still the offset is there.

I can turn on my CTX in ferrous coin, pump the coil 50 times,,no ground feedback whatsoever coming in as coil approaches ground, and while pumping switch to ground coin, and all of a sudden I get quite a bit of ground feedback as coil approaches ground.
If I switch to low trash or high trash I get no feedback as coil approaches ground.

Now, while I am pumping coil after being in say ferrous coin, no ground feedback, switch to ground coin the feedback starts, while pumping Incan select manual GB and while pumping start manual go process keeping the coil,pumping the whole time.
When the manual gB process initiatesI can hear ground feedback the first pump, the second pump slightly less feedback, the third or forth the detectors feddback clears out.
Hence now the detector seems feedback wise as coil approaches ground to mimmick feedback wise what I get using auto ground balance using processes ferrous coin, high trash and low trash.

It is common knowledge the ferrous number is somewhat wild in reporting using ground coin, could this ground phase offset be part of the reason why?

Again assuming my unit is not defective in any way.

Also, if Imselect either ferrous coin, high trash, low trash.
Auto ground balance ,,pump the coil, no ground feedback,,then I can select manual GB, and start process, I hear nothing feedback wise before the manual gB process, during the manual GB process or even after the Mqnual gB process. (Feedback wise)
Telling me the detector was balanced to the ground,
Hence manual GB didn't change anything.



Edited 4 time(s). Last edit at 08/29/2017 11:59AM by Sod-buster.

You've answered your own question.

FERROUS-COIN no ground feedback because it has slow tracking to ground-air. it is intended to differentiate between IRON and TARGET.

GROUND-COIN feedback because it has fast tracking to ground-air. it is intended to differentiate between MINERALISATION and TARGET.

:-)

I prefered on my CTX to run normal and just adjust coil speed-control when in iron or mineral. At the end of the day I had just as much keepers as the other guys.
They probably just ran over the same targets.

Who cut's the most grass?
The guy who runs over the lawn and needs 2 cuts.
Or the guy who takes it slow and just takes one cut.

Both cut exactly the same amount.

Your CTX / BRAIN can only process ground, ferrous, target at a certain max speed. Proceed with caution on slippery roads :-)


Sod-buster Wrote:
-------------------------------------------------------
> scoopjohnb Wrote:
> --------------------------------------------------
> -----
> > VLF 101
> > Shifting ground balance from optimum point alter
> s
> > ID.
> >
> > In order for the FBS2 unit to achieve a consisiv
> e
> > ID in different ground it needs ground balance t
> o
> > be exact every time.
> >
> > If ferrous or mineral shifts ID on the conductiv
> e/
> > ferrous spectrum, you can alter signal processin
> g
> > to achieve the optimum ID "The ID people are use
> t
> > o"
> > If rapidly or slowly changing ground alters ID y
> ou
> > need your GB to follow rapidly or slowly for opt
> im
> > um depth.
> >
> > So no. CTX doesn't have positive or negative gro
> un
> > d balance. It has optimum ground balance all the
> t
> > ime.
> > How fast it changes it ground balance, how it pr
> oc
> > esses the signal, how it displays the TID and au
> di
> > o, they all change.
> >
> > To understand this you need to get hold of an X-
> te
> > rra 705 and hunt with manually pumping the coil
> fo
> > r GB.
> > It can display GB point, it can display GB level
> ,
> > audio and TID span near the entire 360° of condu
> ct
> > ivity spectrum.
> > This unit will teach you an awfull lot about the
> g
> > round your hunting.
> >
> > The XP range of detectors will keep you guessing
> a
> > bout GB point and level.
>
> Vlf 101 tells me, unless some thing is wrong with
> my CTX,,that ground coin is using an offset of som
> e sorts ground bslcne wise vs the rest of the proc
> esses.
> Now, maybe Minelab considers this optimum, but sti
> ll the offset is there.
>
> I can turn on my CTX in ferrous coin, pump the coi
> l 50 times,,no ground feedback whatsoever coming i
> n as coil approaches ground, and while pumping swi
> tch to ground coin, and all of a sudden I get quit
> e a bit of ground feedback as coil approaches grou
> nd.
> If I switch to low trash or high trash I get no fe
> edback as coil approaches ground.
>
> Now, while I am pumping coil after being in say f
> errous coin, no ground feedback, switch to ground
> coin the feedback starts, while pumping Incan sele
> ct manual GB and while pumping start manual go pro
> cess keeping the coil,pumping the whole time.
> When the manual gB process inirates I can hear gro
> und feedback the first pump, the second pump sligh
> tly less feedback, the third or forth the detector
> s feddback clears out.
> Hence now the detector seems feedback wise as coil
> approaches ground to mimmick feedback wise what I
> get using auto ground balance using processes ferr
> ous coin, high trash and low trash.
>
> It is common knowledge the ferrous number is somew
> hat wild in reporting using ground coin, could thi
> s ground pause offset be part of the reason why?
>
> Again assumin guy unit is not defective in any way
> .

HH
Johnb