Serbian "Most Wanted"

[Qiaozhi]

Babel fish....that's why it was called "Babel" at first place!

Actually it wasn't Babel Fish, as it cannot translate Serbian.
I was using ImTranslater, but it still came out as Blabbish.

Thanks for the correct translation.

[ivconic]

So, it was "Babbler fish" - not "Babel fish" !!!
In both cases funny results!
Yeah...Serbian (so as most of slavic languages) is pretty hard to translate correct and directly, to many cases (7) and to many different ways to say same thing.
In case someone have something usefull to post for this forum and can not write on English, i would be glad to translate. No problem.
Regards!

[Magma]

.....

Gospodo detektomani, nesto smo se uspavali. Nije valjda ovaj domaci detektor zasluzio da ga zakopamo ima i u njemu nesto dobro, ako nista drugo barem je nas ( domaci). Pozdrav svima na sajtu.

About CEZAR , see http://www.antikvarnica.com/forum
(na srpskom je)

[Qiaozhi]

So, it was "Babbler fish" - not "Babel fish" !!!
In both cases funny results!
Yeah...Serbian (so as most of slavic languages) is pretty hard to translate correct and directly, to many cases (7) and to many different ways to say same thing.
In case someone have something usefull to post for this forum and can not write on English, i would be glad to translate. No problem.
Regards!

Thanks Ivconic!

[ivconic]

Ok. Ultimate Haze this is on your demand.
I am reposting now basic schematic again to void any confusion.
This is schematic which should be taken as the one to start with.

[ivconic]

This is basic pcb. Tested and accurate.

[ivconic]

To adapt Musketeer coil to work with this detector, task is easy. C6 should be replaced with capacitance between 470 and 680nF. This type of oscillator is sensitive to supply voltage level. So if we choose 9V as supply voltage than C6 should be 470-500nf.
To adjust wanted voltage you can use any combination with 78xx regulator and proper zener diode connected to ground pin of 78xx.
I am using 7805+4V7=9V7.
7809 alone can be used with wire jumper instead zener, also.
Obviously oscillator is taken from White's Classic. Medium power oscillator that can provide up to 22Vpp amplitude of signal (+/-20% depending of supply).
Funny thing is that Musketeer coil is designed for 5kHz operating frequency, while with this design it works between 7 to 8 kHz, and it is working excellent!
Most probably because RX coil is wideband.

P.S.
For C6 use highest quality capacitor. There are differences when i tested ordinary plastic "noname" 0.47 cap and high quality WIMA 0.47 cap. Pay attention on this.

[ivconic]

Next, very important thing U1 and U4!
TL064,074,084,LM324...can work but generally those are bad choice.
I experimented much and found out LF347 as most probably best choice for U1 and U4.
I asume there are rich choice of various opamps that can do job here very good, but from those i have in my collection LF347 so far showed as best.
Huge difference once i put LF347 there! Huge!

[ivconic]

R12 (100 ohms) is better to be replaced with 200 ohms trimmer. Adjust it to get highest possible amplitude at TX out. Keep sinus shape of signal. Once it start to be distorted turn back R12 trimmer to keep clean sinus.
R16 is GEB trimmer. Lower R29 to 1/3 of discriminating level and leave it for a while there. Than adjust R16 to completelly reject ferrite rod. Once is done,turn R29 to 3/4 and check discrimination on some soft iron item. Black iron pliers can be good choice to test with. At 3/4 adjusted Disc iron pliers are not fully rejected, but ocassional "cracks" are audible from speaker. It is ok.
Now...take small and thin silver coin and check with it. If not detected or detected with weak signal, adjust R21 for better detection.
And that is all.

[ivconic]

Now...if you don't like audio (i didn't), you can improve it by adding 1uF (non polarized) from base of Q8 to minus rail. You will get "wider" audio response.
Next thing; add 10nF between C and E of Q8 and you will get very nice "bell" audio (like on Garrett GTI2500, famous "bell")!!! " ..More cowbell....!!!"
You can combine those two mods by selectable switch - best option. At the end ; using that switch you will have 3 type audio option!!!
Using more switches you can have more options. Original audio, with mod1 only, with mod2 only, with both modes = 4 types!

[ivconic]

I experimented with D3 (2V7) also. I suggest use of 4x1N4148 in serie and reversed. Almost the same thing as use of 2V7, BUT i get a bit better response.

[ivconic]

And last for now;
this pcb is checked and proved. I already made dozen detectors using it.
But generally i don't like it. So i started to draw another pcb. Prototype is already made. Now in progress of troubleshooting. Once i checked it i will post it here...
Enjoy!

[ivconic]

Ah yes... on one of my prototypes i replaced 555 audio with already well known 1265/66 audio stage (LM393) and i got much better audio! Almost the same as on 1265/66. Advantages of this option are freq. and threshold adjustments that now are available. In that case R39 must be lowered to 15-22K.

[ivconic]

Once this detector done properly..wow! It turns to be one of most deepest i ever saw!! Of course using Musketeer 25cm DD coil.
I also tested Excellerator coils (for Musketeer) with this detectors. 32 and 36cm DD coils. I got such results..that i am affraid to post those here - you may think that i gone mad!
With 36cm DD Excellerator coil, this detector is deepest beast i ever saw so far! Stabillity is great. Disc is not perfect with larger coils but good enough in most of the cases.

[WM6]

With 36cm DD Excellerator coil, this detector is deepest beast i ever saw so far!

Good news .... thank you ivconic ... tested in soil or air tested?