GC-1023

[bernte_one]

hello sido

same problems as you on the eastern sea beach in germany

is measure the same pins as you but i think i have another maybe newer version of this detector see my pcb photos all made in smd
can be that the chinese save on the other end some wire for the coil but it works
your measurements can be right

i use the 4070L lcr meter from china the testing cables and pins a crap bought new one rest is ok i measure 3times every one when i get every time same result i must be correct

[sido]

Hi Bernte, Both our measurements may be correct. I have heard people say that each coil must be tuned to each detector which probably explains the difference in our readings.

It may be that your updated SMD board version has a slight difference in component values chosen in the RX preamp and op amp configuration only. The rest of the circuit should be the same for both board versions.

You may have the pre-amp and op-amp already boosted from factory (more gain), therefore the RX coil windings and inductance measurement is less in your readings to compensate the difference in overall gain.

This is most likely done by the Chinese factory so to be saving $$$$ on the extra unnecessary copper wire use. (copper is very expensive nowdays)

Where as the TX section might be the same in component values chosen and coil windings as mine for the 6-6.7 Khz tune operation, similar reading to your detector of around TX 2mh and 7 ohms.

What does this mean? Well to build a bigger coil, lets keep the TX inductance of around 2mh the same and experiment with the RX windings, either more or less (more less). In my case i have boosted the pre-amp section and increased the op-amp gain already, so i might stick to the RX value of around 2mh like your reading and see what can be achieved.

If i go by my value of RX 9mh, i will most likely run into to much gain and many problems i think. Previously i attempted to make a large DD coil (16 inch) a while back and became very unstable, maybe cause i stuck to the RX inductance of 9mh, wrong wire gauge and was unable to null the coil properly.

For a small coil its fine, but a larger coil will be influenced more as a larger receive signal gain adds more RF and mains voltage interference. And to further compromise that coil i did not shield it either, so that may have not helped experimenting inside the house..

As a experiment i used a coil of 10 inch diameter which is shielded (unknown TX frequency) but at least it is shielded and worked quite good (extra 2 inch depth on coins) See below Pic. So this is promising that a larger coil can be used as long as shielding is used and done properly.


If only we can see a internal picture of the original coil of what it looks like inside the housing, we can then have a idea of the set up used. I know its concentric in design with the bucking coil on the outside winding and TX and RX winding on the inside.

Another point to note, i believe the right copper size wire is needed to achieve the best performance on a larger coil due to resistive values needed. which one? do not know, just experiment with many wire sizes and see what we can achieve.

Sido

[Qiaozhi]

If only we can see a internal picture of the original coil of what it looks like inside the housing, we can then have a idea of the set up used. I know its concentricin design with the bucking coil on the outside winding and TX and RX winding on the inside.

That is incorrect. It will be either TX on the outside, and RX + nulling coil on the inside (most likely configuration) or TX + nulling on the outside, and RX on the inside.

[ivconic]

Coil from Sido's posted photo is good coil.
I had 3 of those.
SMW is working splendid with it.
It is Chinese copy of Fisher's coil, no doubts in that.
Coil is pretty good quality made.
TX is outside (larger one) and RX is inside. Feedback is part of TX coil and applied around smaller RX coil.

[ivconic]

hello

yesterday ich checked my GC 1023 20cm coil
it seems to be different to the one above which has 2mH and 9mH

my coil specs are:

1,93mH 7R
2,65mH 15R

the coil inductance difference seems to be like the older tesoros
i think the measurement is not 100% correct -the pins were hard to get
but a difference of 0,7mH seems to work maybe also less? 0,5 or 0,6
i will try it with diy coil dd shape coil with 28cm diameter
report follows

Yes, there are 2 different coils that looks like that. One with exactly the same specs as Fisher's coil and another with specs you just noted.
I think you don't have luck, because your coil is the worse one...
I had 3 coils with specs like Fisher's and one with specs like your coil.
Those 3 i had can be used with Fisher's and SMW so i used them with my diy SMW's ... while coil with specs like yours turned pretty useless to me...

GC1023 is pretty unstable and useless for my account, but it is having indeed high quality enclosure and splendid shaft so as pretty nice coil.
So i used all 3 GC's with my SMW pcb instead original one!
If GC can be bought cheaply - than it is worth to be bought and "updated" with better machine... like mentioned SMW...
I payed mine 120e each. Which is indeed bargain, considering splendid shaft (usually 50e least), very nice, robust and high quality detector enclosure (20-30e such ones) and indeed nice, usable and good quality made coil (similar quality and specs can cost over 100e).. so at the end GC is worth to be bought and modified.
Funny... seems few Chinese manufacturers shared the same production line for such enclosures...

[ivconic]

Proof that it is actually Fisher's coil enclosure design copy:
Also coil specs are pretty close to Fisher's coils specs, almost identical.
That GC coil will perfectly match Fisher 1265,1266,1236, CZ6 and few others.

[ivconic]

Just checked...!?
Damn Chinese! It is not the same "GC" i am talking about!
This crap here:
http://www.wellcarpo.com/GC-1023-Metal-Detector-24.html
Is not the one i talked about!
That's why probably coils do have different specs!

I referred all my approvals to this one:

[ivconic]

That's why we often do get confused, because they do name those detectors on the fly, each one can have dozen names! ()

I met GC1030 as MD3030, "Griffon", "Black Rider" , GC this, GC that.... Damn!
The other one also can be met as GC1023, MD3023, "Black Kinght", "Centurione" ...blah..blah..blah..
While the real truth is that all those crappy Chinese products are actually based on just 2-3 different schematics, some of those made to work so so and majority are indeed useless.
Only exception can be mentioned MD3030 (Griffon) at wich at least: shaft, coil and detector enclosure are made very good and can be used as "material" to make much better hand made.
Others... CRAP!

[bernte_one]

that this detector is crap is fact

but it payed itself very fast bought under 40euro within one hour on beach i take over 12 euro with it some other times on playing yard the rest
good to give it a child and collect money for ice (go son earn your ice)

easy to adjust and learn how this machine works and working clean disc

i will not defend it very sensible to wet ground but you can set down sens problem solved
and it gets very little pieces of metal i cant get with some other pi that ive build thats good for cleaning up playing yards in neighbourhood people said to me good job when i dig out some sharp bolts and nails from the sand where kids dig for 40 euro you can make world better

and the good deep machines i take to dig some ww2 relicts which lay down 80cm but not the gc1023 thats clear

[ivconic]

that this detector is crap is fact

but it payed itself very fast bought under 40euro within one hour on beach i take over 12 euro with it some other times on playing yard the rest
good to give it a child and collect money for ice (go son earn your ice)

easy to adjust and learn how this machine works and working clean disc

i will not defend it very sensible to wet ground but you can set down sens problem solved
and it gets very little pieces of metal i cant get with some other pi that ive build thats good for cleaning up playing yards in neighbourhood people said to me good job when i dig out some sharp bolts and nails from the sand where kids dig for 40 euro you can make world better

and the good deep machines i take to dig some ww2 relicts which lay down 80cm but not the gc1023 thats clear

I was talking rubbish actually, sometimes to say that something is "average" or with poor performances - is easier to say "crap"?
Don't know why is that, but it is usual in everyday conversation, English or Serbian - the same; bad habits are bad habits.
As a matter of fact; there is no such thing as "bad" detector. I like them and all those are good enough.
Especially if you have finds with it.
Such average detectors which usually came from China are good enough for shallow beach hunting. Most of those.
There are exceptions like Black Knight, which is also good for inland hunting.
I tested several of those and are pretty stable. Not so deep, but considering just 20cm coil - good enough.
I really don't know what is the problem at those, which turns unstable? Looking inside the electronics - they are descent enough. Coils maybe?
Yes, maybe, but than again; some of those coils also performed pretty well with other hand made?
Tough to be smart about that.
Everything similar, payed under 100e is worth to buy, if not for serious hunting - than surely good as source of diy'ers material for some hand made.
Like i said: MD3030 (Griffon) is best buy so far, bargain, considering very good shaft, good coil and nice and usable detectors enclosure.

[HECTOR]

Didn't get any specific answer on this question so I'm running it through again.

Is there anyone who KNOWS the adjustment function of RV1 & RV2?

I'm assuming that it's "fixed" GB and not "automatic" as I assume RV1 is the internal GB adjustment pot?

What about RV2?

It would be better if I had an idea of what I'm doing before attempting any tweaking.
My Cibola sucked in my soil before I added the GB. Maybe the same situation with the 1023?

Have had it open but haven't touched RV1 or 2.
I'd be up for doing any mods to make it a better machine.
Thanks for keeping this post rolling!

Haven't even taken this thing out of the yard yet

[bernte_one]

Haven't even taken this thing out of the yard yet

i dont now right now wghat you can adjust at the trimpot 2

so better go out and test it and then think about what you want to improve

mine works good cleaned up my new yard last weekend found a lot of smal sharp metal pieces and spacers i was suprised at which depth i had to dig for such smal pieces

so first keep in mind the spell " dont do any changes at a working machine"
the only thing that i do the next days will be only a new coil (diy)
because original is sensitiv at wet ground maybe a problem of bad cabling and shield

[sido]

I am back after a near death experience, my memory is not so clear so bear with me, being involved in a motorbike accident last month i was told. Never again will i pursue a bike with a motor. The automobile drivers here in Australia dont care and are not so watch full of motorbikes and bicycle's in general.

Ivconic, which md3030, it seems the Chinese named a few different types, md3030 and md3010, bit confused here....?

The md3030, is that the one with the LCD display from Kellyco who branded it as md9030/9040, seems to be just as sensitive as the MD1023/GC1023 with a slightly bigger coil?? turn the sensitivity down, will help...

I have the MD1023 and the MD9030/MD9040, even though the circuit board says MD3010, just does not seem to be correct.

Sid

[bernte_one]

hello sido get well soon

can feel with you- got many injuries by motorcycling and lost good friends at crashes
was motocycle driver at german army was a very good time but i gave it up at the end i love my life more than speed

[HECTOR]

GB Successfull

Finally got a chance to take the 1023 out to the test garden and adjust GB RV2.
No wonder the thing was going off on the ground! It was WAY OFF!
Now I get a clean hit on a quarter at 6" and all metal even works now!!
Discs out nickels just before tabs at center adjustment.
NOW IT"S USEABLE!! I just need to figure out it's strong points so I can put it to use as a back up or special purpose detector.