Please Max gift pack

[metaldetector107]

Dear Max
I hope you are all ok.
please if you have time i need your help

1-my TGSL frequeny is 16.2 16.3 khzwith digital multimeter which has frequency meter as well.
2-the pin 12 of 4024 same frequency which should by have
3-detection depth not bad but dicrimantion changes which i think related to phase shift
4-i have made your last coil 30cm from page 105 i made a circule with 30cm and made it halve the 88t for tx
and 92t for rx.
5 please give me detail about deepest OO coil for coinshooting because it easer than
DD shape for me i dont understand DD well exept if you have printable diagram with exact measurement
thanks alot

[Max]

Dear Max
I hope you are all ok.
please if you have time i need your help

1-my TGSL frequeny is 16.2 16.3 khzwith digital multimeter which has frequency meter as well.
2-the pin 12 of 4024 same frequency which should by have
3-detection depth not bad but dicrimantion changes which i think related to phase shift
4-i have made your last coil 30cm from page 105 i made a circule with 30cm and made it halve the 88t for tx
and 92t for rx.
5 please give me detail about deepest OO coil for coinshooting because it easer than
DD shape for me i dont understand DD well exept if you have printable diagram with exact measurement
thanks alot

Hi,
thanks, I'm a bit busy these weeks, lot of stuff to do... lot of work...

1. uhm, not good I don't know if is multimeter bad reading or else. It's probable your coil and/or capacitors at oscillator must be changed to match exactly around 14.5Khz, say that anything between 14Khz and 14.75Khz is good.
2. pin 12 you need half the frequency(4024 act as frequency divider by 2 on first output), so if frequency at osc is 14khz you must read there 7khz; if not that could be related to frequency meter maybe unable to read real value but upper 2x harmonic of signal.
3. if depth is good you're probably right: coil phase is critical for any vlf, you need find right shift between rx and tx signal otherwise it will not work. On Tesoro's coils for tgs and similar you need around 200 degrees. If have no scope it's almost impossible know which phase shift you already have at coil. You can try nulling with meter but then you need make tests with different metals and ferrite, you ideally must null a small ferrite piece of few cms when ground balanced and soft iron when in disc mode, but then detect all coloured "wanted" metals like copper , brass , bronze, gold , silver etc
4. ok, you can try different coils, all similar but all need right phase shift for real good disc to work, my coil it's not an exception to that rule
5. OO coils for tgs/tgsl are not so easy to push to the limit. Are easy to do at average, just need to match inductance at tx for desired frequency (14-14.75Khz in tgs) then you need to add from 5% to 10% turns at RX and find good null and phase. The outperforming OO coils are like that, just are nulled very carefully and phased to angle required for optimal discrimination. You can get nice results with 8'' OO , easy enough for coinshooting, remember that sensitive area is exacly at overlapping in the center.

Kind regards,
Max

[metaldetector107]

Max gift pack

thanks alot Max
by the way i have sent u many MS but but your messate capacity is full
and Mr Ivconic doesnt respond to my messeges Y? i dont know my by cauz i have sent him too many messages anyway
Dear Max i have no choise than relaying on you
so please be patient with me
1- 8" OO is inner diameter?
2-is it as deep as your coil in page 105?
if not please send me printable DD coil diagram for coinshooting if possible
3-the voltage from the +pole of two 10uf capacitor are different i mean pin2 and pin 6 of LM358 why? please

i appriciate