step by step building

[windaube]

hey

I started to build my tgsl, and I wanted to detail the stages of construction with you

for the first step, I start with the coils

I make a template with a 3d printer

tx coil 98 turns, 0.25mm cooper
rx coil 107 turns, 0.25mm cooper

[waltr]

Very nice coil former (template).
Do the coils oscillate at the correct frequencies?

[windaube]

thank you

i don't know how to calculate inductance, or resonance i have 25.8 ohms for RX coil and 24ohms for TX coil
for coil nulling, I am waiting to finish the tgsl
I should receive the electronic part in one or two weeks.

I made an oscilloscope with a mic input and a pc, I hope it will be correct for coil nulling



the rest of the production is coming soon

[waltr]

thank you

i don't know how to calculate inductance, or resonance i have 25.8 ohms for RX coil and 24ohms for TX coil
for coil nulling, I am waiting to finish the tgsl
I should receive the electronic part in one or two weeks.

I made an oscilloscope with a mic input and a pc, I hope it will be correct for coil nulling



the rest of the production is coming soon

Neither is needed if you use the method in Dbower's TGSL 101 pdf.

Connect each coil to the TX oscillator and measure the oscillation frequency on your O'scope.

[windaube]

Neither is needed if you use the method in Dbower's TGSL 101 pdf.

Connect each coil to the TX oscillator and measure the oscillation frequency on your O'scope.

TGSL 101 Manuel : my favorite method is just attach the coil to your completed circuit board (J1) and
measure the running frequency. The Tx should run at 14.5 kHz.

I read on the forum that the tgsl is never at 14.5, because the quality and tolerance of the components is never similar

[waltr]

TGSL 101 Manuel : my favorite method is just attach the coil to your completed circuit board (J1) and
measure the running frequency. The Tx should run at 14.5 kHz.

I read on the forum that the tgsl is never at 14.5, because the quality and tolerance of the components is never similar

Correct.
What is important is the RX coil on the TX oscillator is about 0.55 kHz lower frequency than the TX coil.
This ensures the proper phase shift when DD coil is nulled.

[Nandor]

no!

The correct frequency difference is 1.61 kHz or 22.5 deg phase shift between Tx and Rx. The Geb sample can be adjusted to shift aprox 45 deg and you have to aim for the middle point. Depending on the quality of the components it can be less or more a bit than 45 deg, mine has 44 degrees phase shift.

[windaube]

no!

The correct frequency difference is 1.61 kHz

What is important is the RX coil on the TX oscillator is about 0.55

TGSL PART 1.pdf:
The Tx should run at 14.5 kHz......the oscillator should now run at 13.95 kHz..... (14.5 - 13.95 = 0;55 Khz)

TGSL Coil Making.pdf:
On given former
wound 5.7mH for TX and 6.3mH for RX. ( = 0.6mH)

there seems to be an error between Mh and Khz ?

if this is simpler, I find an inexpensive impedance meter for $ 8 ....

[waltr]

no!

The correct frequency difference is 1.61 kHz or 22.5 deg phase shift between Tx and Rx. The Geb sample can be adjusted to shift aprox 45 deg and you have to aim for the middle point. Depending on the quality of the components it can be less or more a bit than 45 deg, mine has 44 degrees phase shift.

I am talking about connecting the RX COIL to the TX OSCILLATOR (13.95kHz) to check it's inductance as per the TGSL 101.pdf document.

It is nearly impossible to measure the Resonate frequency (16.1kz)of the RX COIL and circuit so the method in tTGSL 101 is very good.

TGSL PART 1.pdf:
The Tx should run at 14.5 kHz......the oscillator should now run at 13.95 kHz..... (14.5 - 13.95 = 0;55 Khz)

TGSL Coil Making.pdf:
On given former
wound 5.7mH for TX and 6.3mH for RX. ( = 0.6mH)

there seems to be an error between Mh and Khz ?

if this is simpler, I find an inexpensive impedance meter for $ 8 ....

How good this that meter?
The method in TGLS 101 works very well. I have built two DD coils and a concentric coil from the TGSL using that metho. All three coils work properly.

[windaube]

TGSL 101 pdf

In running the calculations for coil inductances a difference of
just 5 turns is usually the answer for difference of .5mH between the two coils.

The Tx should run at 14.5 kHz...... the oscillator should now run at 13.95 kHz

if I understand correctly 0.5mh = 0.55Khz?

1 - make the TX coil
2 - connect the TX coil and measure the frequency
3 - add or remove wire to have about 14.5khz
4 - connect the RX coil, add or remove wire to have -0.55khz?
I'm good?

I have a garrett 200i and a minelab vanquish 440 but I want an analog detector.
too much digital, no flavor, I think the tgsl can become my favorite detector


Thank you very much for your help ! you are true professional, and true passionate !

for inductabce meter iam found this :
https://www.aliexpress.com/item/32797743484.html

[Qiaozhi]

I bought one of these on Amazon in January. Very good value for money.
https://www.amazon.co.uk/Capacitance...t-items&sr=1-1

[windaube]

I bought one of these on Amazon in January. Very good value for money.
https://www.amazon.co.uk/Capacitance...t-items&sr=1-1

he seems to be really good !

i was trying to make pcb but i ran out of iron perchloride

so I recreated the pcb with "dip trace", an official pcb and a pcb with the 2 ton mod (experimental)
I ordered 5 pcb of each model
I'm ready 100% soon

[windaube]

Hey

I have two quick questions:
1 - I have seen people use grafiit paint in coil enclosures, It's a good idea ?
2 - to finish the coils I saw the epoxy resin, is there another method? I think of expensive foam

thank you so much

[Carl-NC]

Hey

I have two quick questions:
1 - I have seen people use grafiit paint in coil enclosures, It's a good idea ?
2 - to finish the coils I saw the epoxy resin, is there another method? I think of expensive foam

thank you so much

1. Graphite paint is fine for VLF, many manufacturers do this. For PI, you either need multiple coats of graphite or a better paint, like nickel or copper.

2. Depends on the coil. For mono and concentric the foam will work fine. For DD in a spider shell, you probably need epoxy to prevent falsing. DD in a solid shell will probably be OK with foam.

[windaube]

1. Graphite paint is fine for VLF, many manufacturers do this. For PI, you either need multiple coats of graphite or a better paint, like nickel or copper.

2. Depends on the coil. For mono and concentric the foam will work fine. For DD in a spider shell, you probably need epoxy to prevent falsing. DD in a solid shell will probably be OK with foam.

thank you so much

I will use resin to be sure!

I received the measuring device and .... nothing is going well

for RX coil 107 turns = 26ohms - 5.9mh ( normally 6.5 so 0.6mh less)
for TX coil 98 turns = 24.3 ohms 4.6mh ( normally 6.0 so 1.4mh less)

There is a solution ? I have to start over but with a lot more turn ?