TESORO GOLDEN SABRE

[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

[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]

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

[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...

[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]

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...

[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

[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]

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]

you dont need to desolder any thing.


You dont need cal with your traces.


You have too much Rx output - you see the flat tops on the sine wave.

Need to null this better. If all potted up, then maybe too late.

Pot next one with scope on it

[sdesic]

OK, this coil can't be useful ... it is sealed

[sdesic]

Second coil with second TGSL


Coil is hotglued in place

[golfnut]

much better looks correct amplitudes...


Your goal now iis making sure ferrite can be rejected, or not heard by setting the GEB pot. If you can reject ferrite, It will detect all of the good alloys and you made a detector !

[paku]

how many frequency you get when you nulling coil ? khz

[sdesic]

I don't have direct measurements with scope but it can be calculated... from my last screencap

2,5 cycles in 180uS
by my calculations about 13,888 MHz but I not math expert