Question about tgsl

[kt315]

thank you. same situation is not just in your country. we have that but maybe in slightly easy form.
in reality i do not understand why russian tsar period coins are archeology if they have not relation to modern Lietuva.

[waleed]

Hello everyone..well I'm really upset cuz I don't have much time for this project..I will take it slowly, anyway so far I have finished the pcd only and bought all the components..well wish me a good luck

[waltr]

Hello everyone..well I'm really upset cuz I don't have much time for this project..I will take it slowly, anyway so far I have finished the pcd only and bought all the components..well wish me a good luck

PCB look good. Take your time building and checking stages as you build.
The TGSL 101 pdf is pretty good to help show what each section does.

The hardest part is building, shielding and tuning (nulling) the coil.

[waleed]

PCB look good. Take your time building and checking stages as you build.
The TGSL 101 pdf is pretty good to help show what each section does.

The hardest part is building, shielding and tuning (nulling) the coil.

Hey waltr..yeah I know shielding and nulling would be hard but I have oscilloscope and the basic of nulling and so on..I will post pictures when I finish building and the the coils..

Anyway would you recommend building the DD coils or the concentric coils?

[waltr]

Hey waltr..yeah I know shielding and nulling would be hard but I have oscilloscope and the basic of nulling and so on..I will post pictures when I finish building and the the coils..

Anyway would you recommend building the DD coils or the concentric coils?

I have used both DD and concentric on my HH2 PI detector. I like the DD for fields to get more area per sweep but not as deep. The concentric goes a little deeper but does not cover as much area, sensitive only under the RX coil. So I use the DD when targets may not be deep, parks and sport fields and the concentric in woods and for relics.
Others have described the same performance of DD verse concentric with the TGSL.

I have only built and used a DD on my TGSL (very recent build) so far but plan on also building a concentric.
Not sure which are easier to build. The DD seems more straight forward which is why I started with the DD.

I am currently working on my second DD coil for the TGSL. The first one was shielded with aluminum foil and never nulled as deep plus I had a hard time getting the correct phase shift plus detection distance was not as good as other have obtained. The second DD was wound using a 'mechacical turns counter' (I messed up counting the turns) and shielded with Graphite power mixed with Polyurethane 1:1 plus a thin drain wire. This is nulling very well with the correct phase shift. The in Air distance is improved to what others have gotten. Should have this new coil finished in a couple of days.

Dbowers has good documents on building both.
https://sites.google.com/site/dbcoilshells/home

[waleed]

I have used both DD and concentric on my HH2 PI detector. I like the DD for fields to get more area per sweep but not as deep. The concentric goes a little deeper but does not cover as much area, sensitive only under the RX coil. So I use the DD when targets may not be deep, parks and sport fields and the concentric in woods and for relics.
Others have described the same performance of DD verse concentric with the TGSL.

I have only built and used a DD on my TGSL (very recent build) so far but plan on also building a concentric.
Not sure which are easier to build. The DD seems more straight forward which is why I started with the DD.

I am currently working on my second DD coil for the TGSL. The first one was shielded with aluminum foil and never nulled as deep plus I had a hard time getting the correct phase shift plus detection distance was not as good as other have obtained. The second DD was wound using a 'mechacical turns counter' (I messed up counting the turns) and shielded with Graphite power mixed with Polyurethane 1:1 plus a thin drain wire. This is nulling very well with the correct phase shift. The in Air distance is improved to what others have gotten. Should have this new coil finished in a couple of days.

Dbowers has good documents on building both.
https://sites.google.com/site/dbcoilshells/home

Thank you waltr for the info..well maybe I will first build the concentric then..I read everything about building the concentric coils and I think I would not have any problem about building it..but the thing that I would worry about is the nulling..I know there should be RX and TX/BX but when I null it how would I play with the small loop wire between TX and BX to get the deep null? Like moving it around or reducing the number of turns ?

[waltr]

Thank you waltr for the info..well maybe I will first build the concentric then..I read everything about building the concentric coils and I think I would not have any problem about building it..but the thing that I would worry about is the nulling..I know there should be RX and TX/BX but when I null it how would I play with the small loop wire between TX and BX to get the deep null? Like moving it around or reducing the number of turns ?

If you get real close on the number of turns on the Bucking coil then the little extra wire off the bucking coil is just moved around to finish nulling.

DBowers shows this detail in his concentric coil build PDF. There is a loose extra wind to move around.

[waleed]

If you get real close on the number of turns on the Bucking coil then the little extra wire off the bucking coil is just moved around to finish nulling.

DBowers shows this detail in his concentric coil build PDF. There is a loose extra wind to move around.

Oki and I read that pdf file by Dbowers, but another question I would ask and I always think about it. That if I made a bigger coils and with the same inductance and resonance for the original coil, so would that bigger coil be deeper from the original?

[dbanner]

Oki and I read that pdf file by Dbowers, but another question I would ask and I always think about it. That if I made a bigger coils and with the same inductance and resonance for the original coil, so would that bigger coil be deeper from the original?

The short answer is no. The coil size seems to be optimized at somewhere around 8 to 10 inches in diameter, beyond this the ground effects become more pronounced and there is little advantage to depth.
I would strongly suggest you build the DD coil type first, as it is way easier to setup and null. The concentric coil seems easy only on paper, but it is difficult to get it right without much experience.

Make a DD coil first, then you can test your circuit and have a play with all the features to get a good sense of the TGSL operation and how to set the GB trimmer etc, etc. Then you can have a go at the concentric later on when you understand the principles involved in nulling and the final phase offset.

The DD coil goes just as deep as the concentric, it all depends on how much care you put into the construction and proper shielding of your search coil.

Tesoro has a stock widescan coil (DD). So the tgsl works great with either.

[waltr]

Good answer dbanner

[waleed]

Thank you for the useful reply..I will post when I finish the board and make some tests..

[dbanner]

Good answer dbanner

Sometimes, on rare ocassions, I do get it right.

[ripsdevala]

Anyone know how to add gain pot connection? Need to reduce gain for high mineralised soil... Beeping everywhere

[dbanner]

Anyone know how to add gain pot connection? Need to reduce gain for high mineralised soil... Beeping everywhere

Yes. You can put threshold pot here as in pic. I did this mod and it worked very well. I had more control over the sensitivity. It is just the same with the pantera and silver sabre schemes. So now the first pot is called SENS and the new pot is called THRESH.

[ripsdevala]

Yes. You can put threshold pot here as in pic. I did this mod and it worked very well. I had more control over the sensitivity. It is just the same with the pantera and silver sabre schemes. So now the first pot is called SENS and the new pot is called THRESH.

Thanks a lot dbanner

Will add to the neglected board.