TESORO GOLDEN SABRE

[Op04]

Hi,
If making tgsl is hard then try to build eldorado first, I suggest. Tgsl coil also work for eldorado. Goodluck. Oh ya making coil, nulling, cap resonace also ground balance, is hard part. Took time, many reading! Almost forgot JFET type is crucial. If possible, I took KT advice buying after market coil will help a lot.

[cristiano.sar]

Yesterday morning I just balanced my coil and it worked perfectly and glued it with fast glue to the casing to keep it in place. Although, at night, I put resin on it and today I connected it to the detector and it just keeps beeping. Maybe the resin unbalanced the coil (moved the coils inside the box) or may be due to the resin is not fully dried yet and it influences the balance?
Next time I will probably not use resin this way.





Thanks.

[kt315]

you did BIG mistake. you vastly increased weight of coil by resin. now your coil is just a garbage.

[mostafalesnar91]

1.4*20ms=28. 1/28=0.035*1000=35khz

why??
shouldn't it show 14.5khz???
20us time/div false or true???
5 vol/div tx false or true??
10 mv vol/div rx false or true???

[mostafalesnar91]

1.4*20ms=28. 1/28=0.035*1000=35khz

why??
shouldn't it show 14.5khz???
20us time/div false or true???
5 vol/div tx false or true??
10 mv vol/div rx false or true???
[ATTACH]58099[/ATTACH]

[kt315]

[ATTACH]58100[/ATTACH]

do you see "8" coil there like Cx in this pic?

[mostafalesnar91]

no

[mostafalesnar91]

Yesterday morning I just balanced my coil and it worked perfectly and glued it with fast glue to the casing to keep it in place. Although, at night, I put resin on it and today I connected it to the detector and it just keeps beeping. Maybe the resin unbalanced the coil (moved the coils inside the box) or may be due to the resin is not fully dried yet and it influences the balance?
Next time I will probably not use resin this way.

[ATTACH]58097[/ATTACH]

[ATTACH]58098[/ATTACH]

Thanks.

My friend, you are telling me how you balanced the coil, I want a complete explanation, please help me
What was the frequency and inductance of your tx?
What was the frequency and inductance of your rx? How did you null?? Tell me from beginning to end
How did you adjust the scope??
What did you set the time/div to??
How many did you set the volt/div tx and rx to??
How does this shift happen under what conditions??
No matter what I do, I can't get 20 degree phase difference through lm358 pin 5!!

[kt315]

What was the frequency and inductance of your tx?

FIRST RULE. inductance TX under the frequency. you must get 12-14 kHz. no inductance itself for self -!! JUST for frequency.
do it.

[mostafalesnar91]

What was the frequency and inductance of your tx?

FIRST RULE. inductance TX under the frequency. you must get 12-14 kHz. no inductance itself for self -!! JUST for frequency.
do it.

with multimeter 14.5 but with scope up 30khz on 5v and 20us

[cristiano.sar]

My friend, you are telling me how you balanced the coil, I want a complete explanation, please help me
What was the frequency and inductance of your tx?
What was the frequency and inductance of your rx? How did you null?? Tell me from beginning to end
How did you adjust the scope??
What did you set the time/div to??
How many did you set the volt/div tx and rx to??
How does this shift happen under what conditions??
No matter what I do, I can't get 20 degree phase difference through lm358 pin 5!!

I'm not good at electronics, but what I did was:
1 - Ensure TX coil oscillation is around 14.5khz
2 - Fix the TX coil firmly to the casing
3 - Put the ground balance pot at middle.
4 - Put the coils in an electric quiet place and away from the ground.
5 - Connect pin 1 of TX to channel A, at 5v/div, 20us
6 - Connect pin 7 of LF353 to channel B, at 0.1v/div, 20us
7 - Move or deform slightly the RX coil until you get the desired result

About the coils inductance I don't remember exactly but they are very near the documentation specifications.

That's more or less what worked for me.
Thanks.

[waltr]

Tell me something, preference with inductance or frequency
Which of these two must be correct? Why didn't you say anything about u103 lm358 pin 5? This IC is responsible for adjusting the 20 degree shift spectrum. Of course, I tried it, but this is my test results.
[ATTACH]58093[/ATTACH]
[ATTACH]58094[/ATTACH]

U103 a & b are the integrators after the sampling switches. These are AC coupled so not a good place to do null measurements.

Some people measure with scope are TX & RX coils. Here the RX signal will be very near Zero when coils are nulled. I and others measure at output of RX pre-amp, U101a. Here the signal may not be zero. All the coils I have build for the TGSL have small but non-zero at output of U101a since this amp does have a gain of about 50.
More important than zero amplitude is the 20? phase difference as described in the document you posted.
If my memory is correct I was getting 10's of mVpp at U101a-7. The TGSL works very well with these coils.

[mostafalesnar91]

thank you guys

[mostafalesnar91]

Tx ind=5.83 freq=14.46
Rx ind=6.36 freq=13.86
The shift does not happen at all, just by moving the rx, the wave amplitude shortens and lengthens. That's it

[Op04]

Which coil are you using? Is it on post #6142 ? From appearance that looks ok among your coil. (You can shield it later, many shield material can be use, I don't like foil and copper I use another). From that #6142 coil
1.What inductance for tx and rx, resistance value each coil?
2.Can you moving rx and tx about 2-3mm apart from that position on your photo?
3.That still movable right?? Sorry I not deep following your post.