Serbian "Most Wanted"

[ivconic]

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Hi,Ivconic!I matched all 3 tranzistors in Rx stage with hfe 250 to 300.But for Tx I put with hfe 400.Is too high?I have and with hfe above 500.Isn`t that switches come because of high sensitivity?When no coil connected it starts sound before my GSM start ringing

Ah that!??
It is normal behavior! Many of original detectors are acting the same. Original Fisher 1266 is going crazy from cell phone, Musketeer too, Explorer SE also....
Dont't worry about that....and kill cell phone! (Use hammer on it!)

[ivconic]

Yes that makes sence now; that "switching"! Original fisher 1266 is acting exactly like that, "switching" shortly and producing unpleasant threshold hums all the time, as long as cell phone is handshaking with cell net!
I exeprienced that few times on the field, last autumn. All of the sudden it goes crazy with "no reason". Until i found out that cell phone from my pocket is provoking that!

Musketeer is acting simillar. But Explorer SE is going "vahhh vahhh" with crazy jumping cursor on LCD display..

[ApBerg]

Hello Friends,

Together with friend Nakky we made Caesars most wanted. It is as Ivica say's a sensitive detector, think it wil do a good job on ‘heavy ground’ ,but the disc is not as good as the teso's. The audio part... I love it; it is the version with the 555.

If you use a piezo (with trafo) you can adjust the right freq. and volume ,....
The neighbours love me for that sound…..

Succes all,

Ap

[ivconic]

Hello Friends,

Together with friend Nakky we made Caesars most wanted. It is as Ivica say's a sensitive detector, think it wil do a good job on ‘heavy ground’ ,but the disc is not as good as the teso's. The audio part... I love it; it is the version with the 555.

If you use a piezo (with trafo) you can adjust the right freq. and volume ,....
The neighbours love me for that sound…..

Succes all,

Ap

Splendid job!
"..the disc is not as good as the teso's.."
I agree! No DIY that can beat Tesoro's Disc! Also agree.
Now you make second version with 1265/66 audio and you will be even more satisfied!
Regards!

P.S.
I see that you put my favorite type of caps there! Right!

[Esteban]

Hello Friends,

Together with friend Nakky we made Caesars most wanted. It is as Ivica say's a sensitive detector, think it wil do a good job on ‘heavy ground’ ,but the disc is not as good as the teso's. The audio part... I love it; it is the version with the 555.

If you use a piezo (with trafo) you can adjust the right freq. and volume ,....
The neighbours love me for that sound…..

Succes all,

Ap

Hi Appie, hi Nakky. Nice work!

Regards

Esteban

[Pompey]

Hi,Ivconic!In your last pcb with LM393(not 555) must the treshold work without coil connected?Something is wrong with treshold.There is no sound when turn treshold from left to right.Preamp works fine when touch base of tranzistor (after 68nf cap),but I can`t make with treshold to get permanent sound from speaker.And when I turn treshold to the left sound becomes very weak..I check this on three different pcb`s .Last one I made with KF347.

[ivconic]

Hi,Ivconic!In your last pcb with LM393(not 555) must the treshold work without coil connected?Something is wrong with treshold.There is no sound when turn treshold from left to right.Preamp works fine when touch base of tranzistor (after 68nf cap),but I can`t make with treshold to get permanent sound from speaker.And when I turn treshold to the left sound becomes very weak..I check this on three different pcb`s .Last one I made with KF347.

Looks like everything is alright there... Now i get it!
You are expecting to hear "static" audio!? Noooooo! It is motion detector. To see what is "threshold" on such detector you must connect coil...
Missunderstanding ! Everything is alright at your handmade, don't worry!

Regards!

[Pompey]

But when coil is connected must there be permanent sound when treshold turned to right?There is no permanent sound even when coil connected and treshold fully turned to right.Is that okay?

[ivconic]

But when coil is connected must there be permanent sound when treshold turned to right?There is no permanent sound even when coil connected and treshold fully turned to right.Is that okay?

No. Again no. It is motion type of detector, no static mode. Understand?
Threshold preset there is to smooth up the audio tone or to sharpen it up, depends of your preferences.
You expected constant tone as on some nonmotion detector - or as static mode at 1265/66. "Static" at 1265/66 is actually "pinpoint" mode.
So here is not that case. SMW is motion detector without static mode. Treshold preset serves here to "shape up" the audio tone - not to adjust level of "the treshold" as on nonmotion detectors.
I am not so good in explaining things, but i hope you will understand this.
Connect coil and swing with a coin over it. You will hear "beep beep". At same time turn treshold trimmer from one side to another and you will hear the differences. Adjust it at spot that suit your preferences best.
Regards!

[Pompey]

Thanks,Ivconic!I understand now.I compared SBW with a BG metaldetector from montana.It is motion detector too,but there is a sound by treshold even if no coil connected.Now I understand that your treshold works.I was wrong when said that amplitude was 12v pp.I was in a friend of mine I was making measurements with his scope.Lately I saw that his probe was "x10" So it means that voltage was very high.I want to ask you about coil resonance.Today I`ll make new coil 65-75w(0.45) /165-175w (0.25)For the resonance cap at Rx -must it be connected at the ends of Rx?In paralel of 68nf there is no way to get resonance in Rx.

[ivconic]

Thanks,Ivconic!I understand now.I compared SBW with a BG metaldetector from montana.It is motion detector too,but there is a sound by treshold even if no coil connected.Now I understand that your treshold works.I was wrong when said that amplitude was 12v pp.I was in a friend of mine I was making measurements with his scope.Lately I saw that his probe was "x10" So it means that voltage was very high.I want to ask you about coil resonance.Today I`ll make new coil 65-75w(0.45) /165-175w (0.25)For the resonance cap at Rx -must it be connected at the ends of Rx?In paralel of 68nf there is no way to get resonance in Rx.

??? As on schematic, RX cap is in serie with RX coil. TX cap is parallel with TX coil.
If you made DIY coil according to given datas,than TX cap is 22onF. 470nF is if coil was original Musketeer coil.
Regards!

[Pompey]

??? As on schematic, RX cap is in serie with RX coil. TX cap is parallel with TX coil.
If you made DIY coil according to given datas,than TX cap is 22onF. 470nF is if coil was original Musketeer coil.
Regards!

So if the Tx coil is 2mH with 220nf that gives 7.6khz .How must be Rx coil adjusted,if I make it 15mH .What caps and where to put them?I experimented with a hand made coil 2/11mH. A made Tx coil to generate at about 6khz.After that I put some caps paralel to Rx to get resonance.Then I tried to adjust GEB.By adding -removing capacities to Rx(paralel) I was able to adjust GEB to reject ferrite.Depth was about 30sm for 1 euro.It`s that the right way to adjust resonance on Rx coil?

[ivconic]

I dont understand you?
What other caps than those on pcb?
There is not any cap at RX coil except 68nf in serie, but it is already on pcb? Isn't it?
Also TX cap 0.47 (or 0.22), it is also on pcb.
Nothing to add more.
Make coil and null it, that's all.
Use calculator from the link i gave before to check resonances with your present values.
Regards!

[Pompey]

Okay,it`s everything clear now.Thanks for your help,Ivconic!I must wind coils 2/15mH 2mH with 470n = 5,19khz ;15mH with 68n = 4,98 khz.So I can play with these two caps to achieve desired frequency .If I want to get big frequency => 2mH + 220n = 7,59 khz then Rx must be 15mH + 29,3n = 7,59 khz .(Instead of 470 =220n; Instead of 68n= 39n?)Is this the right way at the end?

[WM6]

all under control?

all under control?