Problems with my new TGSL

[Qiaozhi]

salut seb meme problème pour moi
faut que je trouve le temps de t appeler, mais en ce moment je part tot et rentre tard et du coup je n ose pas t appeler je viens de refaire une autre bobine, et ma foie j ai eu de meilleurs résultats sans blindage que avec je me demande si ce fameux adhésif alu n ai pas trop gros chose bizarre aussi mon pot disc discrimine une pince coupante sur la position zéro et des que je monte un peut le pot il me la prend je viens de vérifier toutes mes tentions j ai -6,27 volts la ou je devrait avoir -5v pour ce qui est du rejet de la ferrite impossible

Please make your posts in English so that others can follow the discussion.

[KRISEMA]

to forgive me qiaozhi, hello seb same problem for me, is necessary that I find the time of t' to call, but in this moment I early leave and return late and of the blow I n' do not dare t' to call I have just remade another reel, and j' had better results without shielding that with I wonder whether this famous adhesive aluminum n' do not have too large odd thing also my pot disc discriminates cutting pliers on position zero and as soon as I assemble one can the pot it takes it to me I have just checked all my try J have -6,27 volts it or I should have -5v as regards the rejection of impossible fer

[golfnut]

If when you adjust overlap for a decent null and the phase difference between Tx and Rx isnt 20degrees - is there a fix for that?

Steve

[dfbowers]

If when you adjust overlap for a decent null and the phase difference between Tx and Rx isnt 20degrees - is there a fix for that?

Steve

Steve,

I think If your resonant frequencies are off, it may be difficult to adjust to 20 degrees.
Maybe try adding or subtracting RX tuning caps.

Don

[golfnut]

Hi Don, I scoped mine last night and I was close to 180 out. (I had added a small cap to the 100pF to help geb...)

I reversed the rx coil and was getting a big double hit , took cap off. Still get a double with close targets in air - but good single tone in ground targets.

about 25 degree lag on Rx null leakage.

(Also disconnected iron channel - all metal too troublesome on uk sites hundreds of tractor bits - often bith tones - lots of digging iron.)


I used to get uk 20p 5" deep in heavy soil - from 2" above soil
now I get
uk 20p 5" deep in heavy soil - from 5" above soil

No iron falses, (as its off) good non-Fe geb. I can pump without falses.

Tomorrow having a go on a site with a Saxon Settlement in adjacent field - with Celtic silver finds. I will show if I get anything. Its a bit fished out - but who knows

Also no oscillation - I think the 180 was part of reason for osillation. Also I had in the past reduced the gain of post mix amp 1Megs.

Also my preamp has 330R and 15k - same gain - lower noise

Thx Don

[Dr Vel]

I bought an IGSL-TGSL board off ebay missing a few parts which I have installed by studying the schematic. There are a few trimmers which I cannot find information on as to what procedure is used to set them. TR1 to TR5, only TR3 being mentioned - set for nice TX sine. TR1,2 are connected from their opamp minus inputs to ground (U4 pins 6 and 10); GEB to Ferrous and GEB to non ferrous. Also TR4,5, Disc and Iron threshold. First, am I correct all 5 are trimmers on the board not external pots, and how do I set them? My other question is it came with 4 single turn pots. Would it make for a better MD if the external pots P1 and P2 were nice 10 turn types instead of using the single turn ones? Or is this overkill and not needed.