TESORO GOLDEN SABRE

[Max]

sorry forget to upload

Hi,
yes it is like I have done on mine.

In the circled area, where shields overlaps, put some tape or other insulant media... to prevent making a connection between shields there.
Only connection by wires as in drawing.

Best regards,
Max

[Max]

Then how?
And in what kind of troubles?Have I burned anything allready?
Please corect this picture!?!?
Thanks

Hi,
No need of correction! Picture is ok... just make that insulation between foil of the two shields. Then make as in the picture.

You can't burn anything that way... touching shields... but maybe you have done a mistake on circuit assembly.

Don't know... try the test I suggested and report results.

Best regards,
Max

[tiktak]

hi

When I have removed this LM358 no sound at all and also not working?
What shell I try next?

[Max]

When I have removed this LM358 no sound at all and also not working?
What shell I try next?

Hi,
-Remove TR10, reconnect U107 (lm358 )... test.
-Then also measure voltages +V and -V and report.

Best regards,
Max

[nelson]

Hi Max, yes i think this is the hardest part of the project.
Anyway i ll keep traing until i get good results.
Yes i agree in this case that inuctance is not to important. I just discover that if you made the coil to match impedance btw 19 and 22 ohms, you are geting closer and then if you mesure inductance you get the correct values (21.6 ohms and 5.9 mH for TX coil). Now why this detector must mach 19 to 22 ohms of resistance?
Has a hamradio hobbist, i learn that most of radiotransivers use 50 ohms of impedance, so antenns must match this impedance. Is the principle of adjusting coils the same has used for antennas.
Thanks Max and friends.
Best regards
Nelson

Hi Nelson,
you are doing a good work on your coils. Let me say that I think you'll gain great experience and skills making your coils. Same thing happened to me.
As ivconic stated many times... inductance matching is not so important if you know what are you doing... just you need to match the tx operating frequency as expected (but also this point you could even change, then making minor changes e.g. on some caps in the circuit) and get a good nulling on rx. Both tx, rx matching expected resistance values within 10% tollerance.
And all your coils will rock.
To answer your question:
I always noticed that adding shield increase inductance. Adding foil you get a increase of inductance, of course. Also with aluminium/mylar I use is the same... but I get less added inductance that way (al film is really thin).
You have to remember leaving always the gap in the shield and have two different (insulated) shields for both coils. Then just use two bare wires to connect to gnd point at cable inside the coil housing. Remember, do not create closed electrical paths between the two shields, this would affect performance, so insulate each other using e.g. tape or paper.
Another trick to avoid too capacitive or inductive added effects is to space the shield from the wound. It's described on BBSailor article on fast monocoil for PI, but principle is always good if you need less cap. or ind. disturbance on shielded coils. Use polyethilene spirals for this... but in VLF just you don't need that stuff I think. I never used in VLF, but only PI coils.

Best regards,
Max

[tiktak]

The + is around 5.7V I use two paralel 9v batteries!
How to measure the negativ rail?I have here only cheep multimeter like on one of the ivconics picture of making DD coil!
I have made DD 28cm with 0,30mm 115 TX ; 127 RX
But when I remouve this LM58 I should cut batt check right?And the md should work?
Thanks

[Max]

The + is around 5.7V I use two paralel 9v batteries!
How to measure the negativ rail?I have here only cheep multimeter like on one of the ivconics picture of making DD coil!
I have made DD 28cm with 0,30mm 115 TX ; 127 RX
But when I remouve this LM58 I should cut batt check right?And the md should work?
Thanks

Hi,
no when remove last lm358 you lose also U107a that serves to drive output stage so your detector can't work.
I ask you do that to insulate fault... then you have to reconnect it.

Measure negative rail putting your multimeter's +lead to gnd and -lead to -V rail.

Best regards,
Max

[Max]

Also 5.7 volts on +V rail is low... ? you would have 8volts !

One moment... 2x9volt batteries parallel ???

You are using too low voltage....

You give 9volts to circuit but lm7808 have a DROPOUT of about 3volts... that's not good! You need at least 12volt source...
could use 8AA cells.

Have you measured current drawn by circuit ?

Best regards,
Max

[tiktak]

Sorry for boring questions but you mean this 358 and this transistor?

[tiktak]

How to mesure the current drawn by circuit ?
If I conect in series 2 9v batteries?
Will 18 be to high?
Or just two week 9B batt. in series around 12?Just to test?
If the batteries are to week coud circuit react like mine?
Thanks again for your attention!

[Max]

Sorry for boring questions but you mean this 358 and this transistor?

Hi,
yes they are: TR10 is the bf245 related to batt-checker.

Best regards,
Max

[Max]

How to mesure the current drawn by circuit ?
If I conect in series 2 9v batteries?
Will 18 be to high?
Or just two week 9B batt. in series around 12?Just to test?
If the batteries are to week coud circuit react like mine?
Thanks again for your attention!

Hi,
you could use the 9v batt in series gettin 18volts that are fine as input to 7808... but you must consider that these batteries could provide few current and last few so aren't so good for long testing. You could use an ac-dc adaptor e.g. like the ones that supply some computer equipment or old phone's chargers... but be sure you got something from 12V to say 24V dc.
What's important is that you get at least that 12volts... so use 8AA cells or whatever suits.

OK- leave current measure out for now... you could burn multimeter if not skilled in it.

Best regards,
Max

[tiktak]

hi

I have remouved this transistor and switch on no sound.switch off put 358 on place and switch on still that nasty sound~!

[Max]

I have remouved this transistor and switch on no sound.switch off put 358 on place and switch on still that nasty sound~!

Hi,
ok now we know that battery-checker is not involved.
So resolder TR10 in place (bf245).

OK. Possible fault is in signal path. You must check PCB following schematic from RX coil pads ahead till you find mistake.

Long work... I know, but only way to know what's wrong.

Check connections, check diodes orientations, check capacitor terminals of polarized ones orientations, check for short-circuits due to soldering ...

Problem is that your last op. amp is in saturation and something before it cause that problem. So your detector keep screaming... cause output stage is always in saturation.

Best regards,
Max

[tiktak]

Hi

Ok,
So, I have to put -of multimeter and according ivconics schematic to check all elements starting from this 15n cap afther RX points on pcb?

I have just tryed with ac/dc adapter only louder sound!
So I will keep testing with two paralel 9V batteries for now.
Which element is the last in this testing?So I can imagine all!