Serbian "Most Wanted"

[Magma]

I made the last version with LM393, but something is wrong, it is the worst sound that i never hear. Only differences are for the MPSA13 transistors, i put BC517 and for BD180 i put BD140 but i believe that are similar on their details. Also with Geb i had not the ability to reject a ferrite rod, maybe thedisk was at very wrong position. Today i will check all

I think, you're probably turned to the entrance of the coil in rx or tx.

[Geo]

I made the last version with LM393, but something is wrong, it is the worst sound that i never hear. Only differences are for the MPSA13 transistors, i put BC517 and for BD180 i put BD140 but i believe that are similar on their details. Also with Geb i had not the ability to reject a ferrite rod, maybe thedisk was at very wrong position. Today i will check all

[ivconic]

I will try it....
I never used a 1266 so i am not familiar with it sound. It is not a clear sound, ... when the signal is not strong then the sound is as a broken speaker...

Ah! Which version you made? The last one with LM393 in audio stage or the first one with 555 in audio stage?
Because first version with 555 in audio stage can act like you just described.

[Geo]

What do you mean by "switching". I can not imagine it?
You should hear almost the same sound as on Fisher 1265/66. At 1265/66 there is specific "bang" in audio when target is close and signal is clear.
Can you record it and upload here?

I will try it....
I never used a 1266 so i am not familiar with it sound. It is not a clear sound, ... when the signal is not strong then the sound is as a broken speaker...

[ivconic]

Ohh....
I had only one LF347 so i put it after the RX preamplifier and at the second one i connected a TL064...
Maybe it is the reason of switching sound!!!!!

Regards

What do you mean by "switching". I can not imagine it?
You should hear almost the same sound as on Fisher 1265/66. At 1265/66 there is specific "bang" in audio when target is close and signal is clear.
Can you record it and upload here?

[Geo]

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!

Ohh....
I had only one LF347 so i put it after the RX preamplifier and at the second one i connected a TL064...
Maybe it is the reason of switching sound!!!!!

Regards

[Geo]

BlueMax 950 coil is great for SMV, I'm it
tested, excellent results but it is possible that you will
need to make some additional settings in Rx.
.. You live in Athens?

Hi.
No, i live at a small sity between Athens and Thesaloniki.
I just tried the 25 cm coil from MD5002. Without any tuning it gave me 33cm for a silver coin 23mm on the air. Very very good.
I think that with a fine tuning it will give me more than my Sovereign.
Also i will try it with the Whites blumax 1500 (15").
The only problem that i have is the sound... no good. I adjusted the bias but i hear it as switching, i don't know why.
Anyware, tommorow i will check it .
Regards

[Magma]

Hi. I have 3 coils to play!!!
One 10" from a MD5002. One Whites Bluemax950 and one Bluemax1500. All these coils are tuned inside so detector will work from 5.5 ... to 7.5 Khz.
I will try them, it is winter and i want to spent my time!!!!
But who knows..... if this detector will go deeper than mine detectors, then... who knows

Regards

BlueMax 950 coil is great for SMV, I'm it
tested, excellent results but it is possible that you will
need to make some additional settings in Rx.
.. You live in Athens?

[Geo]

Hi Geo
Complementary coils for SMV:
CL III, Ficher 1235-1266 ....... from my experience

Hi. I have 3 coils to play!!!
One 10" from a MD5002. One Whites Bluemax950 and one Bluemax1500. All these coils are tuned inside so detector will work from 5.5 ... to 7.5 Khz.
I will try them, it is winter and i want to spent my time!!!!
But who knows..... if this detector will go deeper than mine detectors, then... who knows

Regards

[Magma]

Hi Geo
Complementary coils for SMV:
CL III, Ficher 1235-1266 ....... from my experience

[Geo]

Right now i am using 1M3. At some handmades i met 2M2. Just a matter of experimenting. You can try both and see differences. Same thing with R28.
C14 and C16 are 1uF.
Regards

Thank you Ivconic.
I have a Whites 15" Coil so i want to give it a try
Regards

[ivconic]

Hi Ivconic.
I see some differences betwen the 2(your) schematics and the original one.

So R24 and R26 is 1M3 or 2M2???
R28 at PCB is 4k7 not 1K.
C14 and C16 at Prototype are 1n and at your are 1uF.
Please can you tell me what you are use???


Regards

Right now i am using 1M3. At some handmades i met 2M2. Just a matter of experimenting. You can try both and see differences. Same thing with R28.
C14 and C16 are 1uF.
Regards

[Magma]

Details construction of one of my newer detectors, I hope it will help.

[Magma]

What is this, battery department or pin-pointer?

Yes this is battery department for AAA - NiMH batery 800mA.

[Magma]

Interesting. It is difficult to see the detail from the photo, so I assumed it was being manufactured locally. Nice job!

Thank you
handrail for the painting of the Austrian production and other parts used for installation of steam heating.