TESORO GOLDEN SABRE

[jladre]

Hi everyone.. i been wondering if how many percent will be lost in the real ground compare in air test depth?

[paku]

yes kola. thanks for remind now i build success TGSL Its Very Good
need to read many time to understand on this forum hahahah
Im start make TGSL Years of 2012
Now 2015 The success Hahahah Take To Long Time For newbies like me
i dont have expert tools like oscilloscope
all make manual

my engineer say if you want be wise
what you looking that is you tools for use
Hahaha fun

[Koala]

what is big difference 2N2222, 2N2907 plastic one and metal one

"plastic one and metal one" none as far as I can see. The metal can type were more reliable but both are the same now.

be careful the pin outs are different between the metal and plastic.

be careful where you get the pin outs from. There is at least one site on the web that has the wrong pin out for the plastic 2N2222 I found out the hard way. Much better to pull the original data sheet.

[paku]

what is big difference 2N2222, 2N2907 plastic one and metal one

[Silver Dollar]

It's nearly impossible to keep a certain inductance you can only keep it close.

The buck is added until the RX goes to minimum so keep adding wire until it
is the smallest it gets...

[sdesic]

Have you seen this article?

http://www.geotech1.com/cgi-bin/pages/common/index.pl?page=metdet&file=/projects/coplanar/index.dat

Gwil

I have Don's manual for building concentric coil.
But there is no inductivity for bucking coil.

http://www.geotech1.com/forums/showthread.php?20026-Concentric-coil-for-TGSL&p=164373#post164373

sdesic if your RX is 1/2 diameter of TX then the Buck is 1/4 the number of turns of the TX.

So if you used 80 turns for TX then use 20 for the buck. I think it's around .2 mh, it will subtract .2 from
the TX so I use 6.0 for TX then it drops to 5.8 when buck is in line.

I found you should use thicker wire for the TX and buck or your TX amplitude will suffer. I used .5 mm on TX and buck
and .25 mm on RX.

I have some detection but don't know how effective is bucking coil...
Don't know no. of turns as I added few so it would be up to 6.0 and 6.5mH

[Silver Dollar]

sdesic if your RX is 1/2 diameter of TX then the Buck is 1/4 the number of turns of the TX.

So if you used 80 turns for TX then use 20 for the buck. I think it's around .2 mh, it will subtract .2 from
the TX so I use 6.0 for TX then it drops to 5.8 when buck is in line.

I found you should use thicker wire for the TX and buck or your TX amplitude will suffer. I used .5 mm on TX and buck
and .25 mm on RX.

[Gwil]

Have you seen this article?

http://www.geotech1.com/cgi-bin/pages/common/index.pl?page=metdet&file=/projects/coplanar/index.dat

Gwil

[sdesic]

TGSL EDU with 27 cm DD coil works good but it has some rusty iron problems.
It finds old rusty iron and it beeps regularly in disc mode (set to disc out most of iron)
when I dig it up then it is not audible target... is there any solution for this ?

Pinpointing with big coil is also problem.
Sometimes I think all metal pinpoint is in one place and disc in other ... difference of 20-30 cm sometimes.

All metal is too sensitive to small peaces of iron ... can be corrected by lowering sensitivity (and loosing some depth)

Started building concentric coil but I am stuck at winding busking coil over...
Used 0.2 mm enameled wire so I had to change no. of laps.... and need info on measurements TX and RX are as should be 6.5 and 6.0mH.
Bucking coil is x mH ?

[sdesic]

I have bought White's 6000/di pro sl detector so for now building goes to background.

Solved problem with half device working too. Just need few hours for testing new coil.
Weather is bad for 10 days now.
Coil is hot glued and fitted in ABS - votage is about 1.4mV ... got silver and rejects foil and ferrite.
I don't have epoxy but will use polyester resin.

[bernte_one]

@sdesic
if you have problem while nulling big coils make it so:
place the two coil so together that you have best null volltage (under 4mV is sometimes to low)
if you ahve best result you can achieve glue you coil all 2cm with hot glue
and set spacer between the gap
the fill coil shell half with epoxi and let it harden
next day measure the null voltage again
if it has drifted take a very small pieces of foil and place it one one side of the coil and set the null voltage again with this smal pieces of foil
if you found the best place glue it in and fill the rest of the epoxi


@paku
have you finished ?

[sdesic]

Thank you Silver Dollar, I will try it in field (wet grass and bumpy ground).
Just need to fit coils into shell - they are oversize for shell no.1 from Georgi.

Null is a bit problematic with big coils.
Also bending them on parts where they are crossing over each other.

[Silver Dollar]

I measured 10k on the bottom of a Tesoro Coil and 5K on the top.
There are huge variations I think and they are not too important.
I wonder why Minelab uses very low values like 100 ohms per inch?

[sdesic]

That 2k is my lowest result...
but I have measured 15k on 1 cm and measured 4k on 2 cm

so I need to sand it down a bit ... on few places

[sdesic]

I have 2k on whole D shape ... so it is too low ?