PROJECT ETI566

[mehmet_dag]

Hi Dear Baterista, you really make me happy to get answer of you after long time from the last post date. I am really happy to contact you.Almost i lost my hope but you make me hopefull and you give me hope to finish this project.
I tred to install this project at 2002 but at that years i could not find all the parts. By internet nowadays i achieve to found almost all parts originallybut i realll get sad not to make it work. I really want to see to make it work. If you really show my way to make it work, maybe find sthg and really i will appreciate for your kind helps. This project is very important for me. My suspicious events are as is below ;
1. I have some suspicion about radio scrap and board design of mine. I think that i am soldering not right way and by measuring device Uni-T Ut 603 i tried to measure radio variables but i think that i could not achieve to measure rightly. 3 and 4 number legs i measured by ground leg between 50 to 400 nF as Am side . 1and 2 legs are low as Fm side. I could not be sure about variable capacitor value.
2. Maybe i could not install transmitter AC128 germanium transistor. When i installed first time it get very hot and power off circuit. And i realise that trimmer is at 0 value. When i make it 5 it get normal. Maybe i gave harm to AC188 and this Ac188 is new model can be found at Aliexp.
3. Maybe my pot core value not same as project shown. I bought from mouser and my part come to me after 4 months. I bought these parts.

B65671D0000R048 / 871-B65671D0000R048 / EPCOS / TDK for Tx L1 and Rx L2 Ue 1560
B65671+0400A048 n48 400 ue 127 for Rx L1 Ue 127

4. In pdf file it says * If any diffuculty experienced, C4 in transmitter and C1 in receiver could be reduced to 270 pF each. In addition C6 in the receiver could be reduced to 220 pF. I also done this . But still same problem. "Transmitter and receiver works 20 cm. closer, not working at 1 meter distance."

5. I used metal transistor also i bought silicon models. do you offer to change metal to silicon ? ( Silicons bought ones are same for Q1,Q2,Q3 and q6 to Q6 BC549- Q4,Q5 and Q7 BC 559.) Maybe i am settling these transistor wrong i check by diagram it seems ok .

6. All resistor 1/2 watt and % 5 tolerance.

I really go insane not to find solution. I really need your help just give me some time to solve it. My all electronic knowledge confused.

If you want see my circuit photo i could send you by email or like that i could not upload photo to here.

Really i need your help please help me to finalize to make it work as your project.

Thx for your all kindness and appreciate for your reply . Waiting for your kind response and helps.

[mehmet_dag]

Hi Dear Baterista , waiting for your precious guide. I changed radio scrap to change found almost one is 100 nf and the other 150 nf (1 - 3 legs) and result tone comes at 60 cm. I think last step left but still could not find any solution. So your help will be very important for me to have some idea to solve last point. Rgds. Mehmet

[Baterista]

Hello, mehmet_dag, there are no problems with the scrap components, unless you have not checked that they are ok,
The values of the pot colors of the tdk 26/16 look ok to me, they are a little big since the originals were 18/11 or 18mm / 11mm, I used 23/17. But no problems.
The transistors are also ok, unless you have reversed any pinouts.
The values of the coils outside the board are not good, you need to have the values indicated in the project. Maybe because of the 34SWG wire
In my experiments, I finally ended up using 32AWG enameled wire, which is equivalent to 36SWG, so you need to remake the coils with these wires, if possible. They are thinner, and when
make the winding do not let it get too tight or too loose. This is essential for the oscillator operating frequencies to match well.

[MartyJ1963]

Hiya all,,,,Been wanting to try this project myself so I had a go at re-drawing it,,,Hope it's useful to others too,,,Regards, Marty.

[mehmet_dag]

Dear Baterista

The values of the coils outside the board are not good,
I winded Transmitter with 36 swg and results are almost same as 34 swg.
L1 transmitter i measure 203 mH with 36 swg. at the outside of circuit but when i installed to circuit i measured 157 mh.

I will also wind Receiver potcores and i will tell you the result.

And what kind of potentiometer you advise , i change the potentiometer at Receiver and the results was more stable. and i got signal from 1 meter away at each other i think i complete first step but i could not get signal 2 meters away ( Receiver and transmitter distance e i got signal of 1 meter but at 2 meter i could not catch any signal.) Just i changed transmitter potcore to see result. I have checked the transistor legs and i am sure they are at right position.

With my best rgds. Any more advise ? And specially thanks for your kind response and helps.

Sincerely yours.

[Baterista]

Hello mehmet_dag, the potentiometer should not interfere with the result unless they are very worn, but I still think there is a problem with the pot core they should have the correct values with the pot core off the board, but if the results are improving , it is best to move on anyway. Keep me informed of the new results.

[mehmet_dag]

Hi Dear Baterista,

I wounded by 32 awg wire all of them , new results are as is below ;
L1 transmitter : 203 mH
L1 Receiver : 25,3 mH
L2 Receiver : 19,4 mH.

I have wounded normal strecth not tight not loose , i have wounded three times each and check results , more or less all wounding measuremet as above.

But i wil let in to try by this values and let you know about working.

With my all sincere regards.

[mehmet_dag]

Almost i am close Dear Baterista last step left i think, as your suggestion, but what do you think about 33 awg which is about 0,18mm. thickness. I am asking due to L2 receiver with 32 awg same value about 20 Mh. Waiting for your kind suggestions about L2 receiver.

[Baterista]

Almost i am close Dear Baterista last step left i think, as your suggestion, but what do you think about 33 awg which is about 0,18mm. thickness. I am asking due to L2 receiver with 32 awg same value about 20 Mh. Waiting for your kind suggestions about L2 receiver.

Hello mehmet_dag, with the 33 awg wire you will have a higher resistance value, for example, in the L2 built by me the total resistance is 5.9 ohm, to know the effect of the increase in the resistance value
it will be necessary to experiment, you can also decrease the turns of the windings to decrease the inductance of the coils, but I think it is no longer necessary to move with the coils, you now need to change the capacitors
C4 (transmission) and C1 (receiver), I know that you have already tried these changes, but the resonance frequency of the transmitter that is established by the set L1 - C4 - CV1 should be around 20 kHz, and the receiver should have the 3rd harmonic of
transmitter, around 60 kHz obtained by the set L1 - C1 - CV1, and with these higher values in the coils the solution is to lower the capacitor values, it seems good these values suggested by the author from 270pf to C4
(transmitter) and C1 (receiver), also try to change the value of C6 (receiver) to 390pf.

[mehmet_dag]

Many thanks for your kind responses Dear Baterista, you really make me acknowledge person beyond the project. Now with all my same value it seem working now i will adjust the bar and go for trying. Many many thx for your all efforts and well appreciated all your friendship about project.

[mehmet_dag]

And Dear Baterista would you say all coil ohms , i mean what are the each resistance of L1 and L2 receiver ohm and L1 transmitter ohm to check coils wound . Thanks for your all kind effort.

[Baterista]

And Dear Baterista would you say all coil ohms , i mean what are the each resistance of L1 and L2 receiver ohm and L1 transmitter ohm to check coils wound . Thanks for your all kind effort.

Coil Specifications:


RX L1
Inductance without pot core - 78uH
Inductance with pot core - 20mH
Resistance - 2.4 ohm (without pot core)
Capacitance - 210nF (without pot core)


RX L2
Inductance without pot core - 534uH
Inductance with pot core - 17.20mH
Resistance - 5.9 ohm (without pot core)
Capacitance - 648nF (without pot core)


TX L1
Inductance without pot core - 476uH
Inductance with pot core - 160mH
Resistance - 6.3 ohm (without pot core)
Capacitance - 60nF (without pot core)

[mehmet_dag]

Many thanks for your all kind and lovely guiadance dear Baterista. I have at last set up the machine 2 meter away, but i want to ask the jumper role at transmitter. When i uninstalled the jumper signal increased. Receiver jumper not changed any when i uninstalled it. And i tried the machine on ground by a sixty centimeter tray it detect it at almost 1 meter no more depth. I think i have problem at sensivity also. And also i have replaced C1 receiver and C4 transmitter with 270 pf and C6 at receiver to 390 pf. It really changed many and i got signal clearly . And i measured with my new wounds wire turns with 32 awg as is below ;

RX L1
Wound number - 64 turns
Inductance with pot core - 20mH
Resistance - 1.48 ohm (without pot core)

RX L2
Wound number - 200 Turns
Inductance with pot core - 16 mH
Resistance - 5.1 ohm (without pot core)

TX L1
Wound number - 181 Turns
Inductance with pot core - 160mH
Resistance - 4,57 ohm (without pot core)

[Baterista]

Many thanks for your all kind and lovely guiadance dear Baterista. I have at last set up the machine 2 meter away, but i want to ask the jumper role at transmitter. When i uninstalled the jumper signal increased. Receiver jumper not changed any when i uninstalled it. And i tried the machine on ground by a sixty centimeter tray it detect it at almost 1 meter no more depth. I think i have problem at sensivity also. And also i have replaced C1 receiver and C4 transmitter with 270 pf and C6 at receiver to 390 pf. It really changed many and i got signal clearly . And i measured with my new wounds wire turns with 32 awg as is below ;

RX L1
Wound number - 64 turns
Inductance with pot core - 20mH
Resistance - 1.48 ohm (without pot core)

RX L2
Wound number - 200 Turns
Inductance with pot core - 16 mH
Resistance - 5.1 ohm (without pot core)

TX L1
Wound number - 181 Turns
Inductance with pot core - 160mH
Resistance - 4,57 ohm (without pot core)

Hello, mehmet_dag, the jumper is an alternative to include or remove a section of the variable capacitor, in my case the "C1" of the variable capacitor is around 130pF, with the jumper I add C2 and stay around 270pf, the pin Central CV1 is the ground, C3 and C4 generally have around 30pf and are used for FM and have not been used. As for the depth reached, it look good and believe me you probably won't get a better result than any other "professional" 2-box detector, but now it's just tests and adjustments, the resistance of the pot-core is ok, and variations are due to the difference in results from one multimeter to another. Congratulations.

[YIVANKA]

This project looks good