TESORO GOLDEN SABRE

[sdesic]

I have measured :
TX 5.99mH
RX 6.44 mH

I have desoldered RX coil from PCB and tried power up
I have 3,6 mV on RX
desoldered back RX on connector
measured pin 7 250mV with AC voltmeter

Connected scope on TX and pin 7 preamp
here is result

Green is TX

same configuration and with 7 cm x 2 cm block of ferrite on coil


my USB scope is not calibrated to measure voltage

I found that coil is not rejecting ferrite completely - close by (1-2 cm) it rings on two places (?)

will try to play with GB

[golfnut]

No desoldering, measure the output of the preamp. Dont try to make it super low at the expense of the golden phase relationship.


I used one of these which had 2VOLTS PP preamp out and it still found loads.

[sdesic]

You seem to want to make a new one. Ive seen guys make a heap of them before slowing down to learn whats going on.


For sens you need the Rx coil cap combo to be resonant about 75% of the Tx frequency

If yours aint so good, tweak the Rx cap about until it is good.


Getting the phasing right will allow you to reject ferrite at any distance - ( then the ground can be tuned out ) then the unit will not false over real soil.


The null is of secondary importance. ( hope to get less than 0.3vpp at preamp output using a scope) Dont beat yoursel up over it,


If you get a double beep on a valid target , flip the rx coil terminations


Its that simple ( it did take me about 2 years to twig thou ) S

I have two TGSL devices so I wanted to compare. (both Silverdog kit)
My old one had problems with GB but now it is OK
Rejecting big ferrite stick and silver is safe.
I will experiment with it now.
Today I will post oscilloscope screenshots ...
I think that there is about 150-200mV on pin 7... preamp
did not have oscilloscope when I measure it - with voltmeter

must desolder RX on connector to measure directly

[Silver Dollar]

Well I made a lot of different coils but only assembled one into a housing.
I thought I knew what I was doing but the results are not so good. I bought
a working detector so I could see what a good one looks like. It still seems
difficult to set the coils to the null point and know which side of the null
you are on...

[golfnut]

You seem to want to make a new one. Ive seen guys make a heap of them before slowing down to learn whats going on.


For sens you need the Rx coil cap combo to be resonant about 75% of the Tx frequency

If yours aint so good, tweak the Rx cap about until it is good.


Getting the phasing right will allow you to reject ferrite at any distance - ( then the ground can be tuned out ) then the unit will not false over real soil.


The null is of secondary importance. ( hope to get less than 0.3vpp at preamp output using a scope) Dont beat yoursel up over it,


If you get a double beep on a valid target , flip the rx coil terminations


Its that simple ( it did take me about 2 years to twig thou ) S

[Silver Dollar]

I just scored a 7" widescan factory Tesoro coil for $35! It should be here shortly.
For that price I can't see messing around trying to make one myself...

[sdesic]

OK

today I tried new coil and it is working better - disc is perfect (for me)
in field and in all metal mode detector is working slower than in disc
looks like there is a lag between detecting and sound - but just in all metal mode

DD coil is pain in a** to pinpoint with
coil is sounding 30 cm in circle around it - large foil or XY metal
I dug a few holes to China today

next it is Don's CC concentric coil to serve as sniper coil in trashy area
but before that I will try ferrite and coin

[Koala]

great ideas
I must finish new coil and then I will try peace of graphite and penny.

UK penny ... Copper plated Steel in new ... older one then

1985-1992 Bronze

My mind thinks ferrite and I write graphite

Should have read a small piece of ferrite


A while back I read on here that on opening a coil someone found a coin installed at the factory.

[sdesic]

great ideas
I must finish new coil and then I will try peace of graphite and penny.

UK penny ... Copper plated Steel in new ... older one then

1985-1992 Bronze

[DOOLEY]

FOR SDESIC,
only a thought you could try,
ive done it before on a coil that was a bit far out after setting,
it sounds crude, but it works,
although phase will be slightly delayed.
a copper penny on the outside of the coil shell,
on the topside, so you don't knock it off in use,
move it around whilst watching oscilloscope to get your null right,
mark the position, then superglue it !!
paint the penny black so passers by dont ask "what's the penny for !!"
works a treat, although many pure'ists would frown upon it.
LOL.

[Koala]

Coil is in "epoxy" so I can't do that.

No matter it only has to be near. Give it a try. Hopefully you can rescue your coil.

[sdesic]

Try small piece of graphite between the TX and RX move it around while watching the scope you might be able to re null your coil

Coil is in "epoxy" so I can't do that.

[sdesic]

My next coil is fixed by hot glue only.
Remains on place and null.
I need to try it in field.

[Koala]

I tried it and it is heavy and it is rejecting ferrite rod 5-6 cm
Less depth in field testing.
I adjusted sensitivity to half to remain silent.
Not very good in all metal mode - too much false signals - maybe it is my test ground.

Used disc over half to reject foil and to remain stable and silent.

Try small piece of graphite between the TX and RX move it around while watching the scope you might be able to re null your coil

[sdesic]

I tried it and it is heavy and it is rejecting ferrite rod 5-6 cm
Less depth in field testing.
I adjusted sensitivity to half to remain silent.
Not very good in all metal mode - too much false signals - maybe it is my test ground.

Used disc over half to reject foil and to remain stable and silent.