TESORO GOLDEN SABRE

[eclipse]

I will post detail information on the process of making + pics
I ordered the board in a local manifacturing company (pcb with solder mask and print screen -20$), hand made won't be that good for the purpose.
Parts are ordered from Mouser & Digikey.
In local shop I can't even find potentiometers what to say about the LM308, good caps, etc, not to mention the quality is low (some of them are dead on arrival).... real loosers Im done buying components from the shops here.

[ivconic]

Dirceu, nice pcb.
One thing might cause you a problem; 1000uF footprint. It supposed to be 1000uf/25V. You should place there larger footprint....maybe? Maybe not, depends of capacitors you can find in your local shops.

[ivconic]

.........
In local shop I can't even find potentiometers what to say about the LM308, good caps, etc, not to mention the quality is low (some of them are dead on arrival).... real loosers Im done buying components from the shops here.

Huh,story of my life! Same situation here...
More benefits when took components from scrap electronic than from local shops! They even rised prices recently!

[tiktak]

Hi

Hi,
Ha.ha.ha....
Shame but same story with me.
In some shops there are good electronics.But this Mouser & Digikey is a how different story.How long did you wait for a shipping?
And what is your location?
))))

[Max]

uhm... this is more and more a problem today

Huh,story of my life! Same situation here...
More benefits when took components from scrap electronic than from local shops! They even rised prices recently!

Hi,
yes, it's a problem everywhere I think apart big cities... where you find always everything you need, but now not always true, I tested myself many times and I'm now really annoyed by that.

I have 5 shops just near me... and many others at few kms but I'm not satisfied with them all... also !

Problem is that today they raised prices of that stuff with no apparent reason... this stuff needed for TGS/TGSL is really old too! Apart lm308 that was always a pain to find... even 10-15years ago... all the rest are old parts... very common also... really cheap... what for lm393, what for lm358 ???

So what ? They simply don't buy enough stuff... and enough quality parts...and what they have on stock is then limited in number and quality...

THE MOST RELEVANT CAUSE:
I think the fact many repairing services shut down... simply made distributors went out of this components business: today few people wanna repair something like e.g. a TV... maybe 10% than just 20years ago. The rapairing business is often not worth the expense... and people trash stuff and buy new things.

So apart big dealers like Maplin and others... all the rest is just if you need an e.g. switch... or a roll of solder wire... real stuff you need you'll not find 3 times over 4.

Good solution is buy big blobs of components from big dealers... when you find some good offer... I bought thousands of resistors that way... also caps and diodes... pack of 250 pieces also of 1n4148, a real bargain sometimes.

But real problem is still you cannot buy everything you'll need in the future: you simply don't know about!

Kind regards,
Max

[eclipse]

Hi,
Ha.ha.ha....
Shame but same story with me.
In some shops there are good electronics.But this Mouser & Digikey is a how different story.How long did you wait for a shipping?
And what is your location?
))))

Parts from digikey came after 7 days, mouser took 3 weeks - same delivery company (USPS) for both orders - 30$ each (huh.. bad.) I am from Bulgaria.
The only things I didnt order is the cable, and damn even in shop for cables I can't find suitable. Just walked all around the city, nothing.
You are right, its getting harder to find parts, too much cheap electronics and noone repairs or makes himself.

Regards

[DIRCEU]

Hi,
very good work!

It's really good made PCB, did you use a professional service to get them or it's your work only ?

The components seems very good to me for the purpose.

It's really probable you'll get improved S/N from that approach.
Nice to hear good results!

Kind regards,
Max

Hi! MAX

To drew some lines and components at a ready PCB... really its nothing.
The credits should be given to the IVCONIC's efforts to optimize this project and also give to us your results.

Best regards

DIRCEU

[DIRCEU]

Dirceu, nice pcb.
One thing might cause you a problem; 1000uF footprint. It supposed to be 1000uf/25V. You should place there larger footprint....maybe? Maybe not, depends of capacitors you can find in your local shops.

Hi! IVCONIC

Yes. 1000uF/25V. No problems with components here.In local shops I find several sizes for these components.

Best Regards

DIRCEU

[simonbaker]

Hi,
simonbaker.
This is a nice idea for experimental nulling.But I dont see how you can fix the coil in its final position.You see my point.I also hate solder and desolder again but......This are not even shielded.Plus I think that the both windings should be sealed with epoxy at once.And thats the trick.Keeping good null in same time.
I had some average experiance with sealing step buy step.Several layers.
So the windings should be fixed reliable and then sealed at once with epoxy.This way you have net and resistable construction.

Thanks

Yes, nulling machine not for real use, just experiments (and humor - a real contraption! ). I will shield it eventually, but part of test is to see how it works unshielded too.

I will need to learn expertise of making, sealing, shielding real coils soon, like you and others make, very excellent. Advice is always appreciated.

Cheers,

-SB

[simonbaker]

Given the above published photos have the following question:

What exactly is the method of calculating phase difference between TX and RX with two channel analog oscilloscope, so the result is in degrees?

I think: sync on TX signal. Measure width of one cycle. Measure distance RX signal is shifted by comparing peaks. Then make fraction and multiply by 360 degrees.

Example: one cycle on scope is 4 divisions. RX signal is shifted 2.2 divisions. 360 * 2.2 / 4 = 198 degrees.

I hope I did that right...

Cheers,

-SB

[eclipse]

There is a good graphical explaination of what simonbaker says, hope it helps.
Here:
http://www.hobbyprojects.com/oscillo...surements.html

[eclipse]

Almost ready, tomorrow - big day

[rdec4]

I think: sync on TX signal. Measure width of one cycle. Measure distance RX signal is shifted by comparing peaks. Then make fraction and multiply by 360 degrees.

Example: one cycle on scope is 4 divisions. RX signal is shifted 2.2 divisions. 360 * 2.2 / 4 = 198 degrees.

I hope I did that right...

Cheers,

-SB

There is a good graphical explaination of what simonbaker says, hope it helps.
Here:
http://www.hobbyprojects.com/oscillo...surements.html

Thank you for your help.

[Qiaozhi]

Hi,
look at that: it's Qiaozhi's picture of signals at TX, RX (output of preamp) using an original coil (maybe it's an 8'' round ? I've tested an 8'' round an was exactly the same stuff too...I suppose they are about all the same... no matter of size or widescan...spider... etc).

I read about the same on my 9x8'', also... you'll get left shifts of RX signal nearing any metal, but no shift in pure mineral response (e.g. ferrite crystals)

Kind regards,
Max

This picture was taken using a Tesoro 9"x8" coil, but the result was the same for an 8" and a 4" coil. These were all concentrics.

[simonbaker]

Almost ready, tomorrow - big day

Gawd that is gorgeous! I think you should make a separate thread with the whole story of building your detector, experiments, waveforms, pictures of components, why you chose each, field tests - don't forget schematic, pcb files -- so we can drool! Really nice!

-SB