King Cobra PCB

[koohyar]

mr KT315 plz answer me thanks

[koohyar]

Hi Friends
I want to make this metal detector
But first I want to know what is the final authority?
For a gold coin with a diameter of 2 cm
And a copper plate 10 x 10 cm
And a copper 20 × 20 cm

Do you think the ultimate power to 3 meters?
Thanks

hellllllllllllllllllo
Anyone hears my voice?
Is there anyone here?
plz help me

[sinclairuser]

the more i see these finished cobras the more i am captivated by them!, KT315 you have done an excellent job.
after i completed my last project i decided to build another MD, after researching the IDX pro, TSGL and the KING COBRA i have decided on the COBRA
am i right in thinking you dont do full kits?, if so thats ok.
but how much are the boards?.
thankyou aly.

[koohyar]

power of GMT king cobra

Hi Friends
I want to make this metal detector
But first I want to know what is the final authority?
For a gold coin with a diameter of 2 cm
And a copper plate 10 x 10 cm
And a copper 20 × 20 cm

Do you think the ultimate power to 3 meters?
Thanks

[calebsone]

hey kt i found my mistake after i watched your video on youtube about the momentary switch i bought the reverse of the 2 the mode is momentary not the notch i feel very silly for not reading it correctly ordering the right ones now

[kt315]

TX pic you may see in my #358 post. it is very clear enough sinusoidal signal. seems you have some limiting via feedback circuit that fixing the TX signal on some level. this is D2 D1 R1 C6 Q2 R10, accordingly its transmission. check them all. specially check Zener diode D2 and its polarity position at the board again.

best regards

[calebsone]

ok so the rx looks right on the o-scope but the tx looks flat on top of the wave also the discrimination and notch amp looks very wild could the 393 be whats wrong? only asking because it seems like its not gb-ing right i have to max it for mm and mL positions to detect and mid to min for mr to detect but it is detecting at 10in or more but still something cant be right

[calebsone]

ok the 308 in the u 11 spot was bad so i changed it but the tx is still not functioning right i think the 7660 may have got too much current because the 7808 did for sure ill let you know after i change the 7660 and 2907

[calebsone]

ok heres the almost done king cobra i still need some help with the function of it so tonight ill o-scope it and post pics its depth is very low so i think theres something im missing kt were should i measure from

[calebsone]

thanks I just noticed that they were but I dont think thats my problem I used the pn2222a ebc so im thinking its the amps 308s and 442s I found a shop with new old stock they are from the 80s or 70s and I dont know how they were stored thanks again

[kt315]

data sheets are different, you are right. P2N2222 pins position (C-B-E case) is not same like PN2222A has. you can use MPS2222A, MPS3904, 2N3904, 2SC9014 (all are in E-B-C case). either to set P2N2222 opposited 180 grad (I look Motorola's data sheet).

[calebsone]

now before I pull all my 308s and 442s because they are the old ceramic type I just have to ask in the parts list q9 and q10 are they pn2222a or p2n2222a because the data sheets are different I just wanted to know sorry if its a dumb question

[kt315]

DIP8 SO8 board

bought at ebay and just received those adapter boards http://www.ebay.com/itm/180952961067...84.m1497.l2649
now can use NE5534 in SO8 and opamps from trash electronics PCB's.

good luck

[bernte_one]

hello herpes

i think it would be easier to change tx and rx caps to get the right induction / frequency relation (shift)

why not present your project in detektorforum too?

next days i will start to assemble my king cobra

i have some older tesoro coils here also a concentric from the stingray i think it will fit good

kind regards

[kt315]

the wire is same for TX and RX, 0,29 mm diameter. good luck.