COIN HAWK PROTEL SCHEMATIC

[Qiaozhi]

The frequency of the Colpitts oscillator can be calculated using:
f = 1 / sqrt( 2pi * L * C ) where C = 1 / ((1 / C1) + (1 / C2))

Oops!
Nobody spotted my deliberate mistake then?
Of course the equation should be:
f = 1 / ( 2pi * sqrt [L * C])
The calculations were correct, but I just lost the ability to tpye.
Bloody dyslexic keyboard.

[Sean_Goddard]

Geo, nothing special about this design, but I was hoping someone would "prove" it worked as a design as it's my first attempt at a VLF beeper. Als othe high power output oscillator should give it the edge over both the machines you quoted....I hope

I would make a PCB for it but I'm working on an ultra low noise version at the moment. Results are good and I hope ot go commercial with it. Obviously the CH would have been a flop..

[Geo]

Hi Sean_Goddard. I understand you. Simple i believe that it is something between Classic III and tessoro. Maybe good or very good but not special. Never mind...you have designed a detector and i have never designed anything , maybe i am not able to say anything about you...... but i can't. Always i say my opinion ????/
Good luck with the ultra low noise version
My regards

[Qiaozhi]

Geo, nothing special about this design, but I was hoping someone would "prove" it worked as a design as it's my first attempt at a VLF beeper. Als othe high power output oscillator should give it the edge over both the machines you quoted....I hope

I would make a PCB for it but I'm working on an ultra low noise version at the moment. Results are good and I hope ot go commercial with it. Obviously the CH would have been a flop..

In reality TX power is much less important than you would imagine. Even doubling the output power will cause little improvement, if any. In fact, it's quite likely to cause other problems at the receiver.
Your work on an ultra low noise version has a greater chance of success.

[Sean_Goddard]

Thanks for your kind words guys. Geo your opinion is ALWAYS appreciated, and I enjoy reading your posts on this forum. You always raise good points, many of which get the rest of us thinking. This is good .

Qiaozhi, I hear you and agree. Too much signal can saturate the ground, but I am trying to find a way to put out the maximum possible and then cut it back, in other words I am putting out enough to saturate the ground matrix and then back it off a little. In my new design I am doing this dynamically. I have a new way of measuring ground effect by doing this. i ca17.nnot say too much but I think you will work out what I am doing.

I think to double the depth, you have to square the power output, but I have an idea. Background noise (earth signal) levels are around the -127dBm level. So far using ultra low noise components, designing the front end amplifier carefully I can get a signal meaningful signal at around -118dBm. This means VERY good depth, but I am having to use a LOT of DSP power to do this. In the analog domain I can achieve around -105dBm (6dB down is around 4cm depth in real life) so to transmit 0dBm signal, will get you around 105/6=17.5inches (in air) of course the ground signal masks a lot of this, BUT, what if you could determine exactly what the ground signal level is and apply this to the incoming target signal, like antinoise headphones which cut out the outside noise and you hear only the music)? THIS is what I am close to cracking and I hope will give me exceptional performance in a new design.

My only worry is that after coming up with the CH and it not working, how ewell will this main machine do.. Does not look promising does it??

[ivconic]

Many questions opened...


Many questions opened now.....
Look, frequency is not main problem, i know how to adjust it.....Main problem is that CH acts very bad....Even with coil disconnected it produces sound,but not continous.....beep,beep,....pause...beep,beep,...p ause.....It reacts on threshold pot...also on few other pots...but different,no rule....
No mistakes in pcb...I even made another,one-sided pcb (15x15cm...Huh!) just to make things easier to see,check and follow...while in experimenting "phase"....It is so easy to trace any possible mistake now,on this pcb.....No mistakes....respecting schematic. Everything acts abnormal???
Of course no detection at all. Voltages are good, as expected to be. No i do not have osci. right now, i will provide in few days.
I have 2 DPulse to finish,and few other detectors in next 10 days, than i'll come back to this subject.Schematic looks interestin enough for coinshooter, but honestly, i wanted to make it "sweet&easy" .....it turned to a nightmare....
I am passionate coin collector,therefore i wanted good coinshooter just for my needs....what to say? I'll stick to CL3 for now...
regards!

[Geo]

Hi Ivconic. Anker A50 or ss60 is a very good detector. It have a small problem with ground balance and is a difficult project to construct but it is a very good detector (more..more sensitive than CL3, and very nice sound). When you will receive your new oscilloscope try it (if you have time). Ohh first finish the 1266 to tell us about it
Regards

[Qiaozhi]

I think to double the depth, you have to square the power output, but I have an idea.

Actually I believe it's much worse than that, and could be as much as 64x.

[ivconic]

...


I also noticed that square signal can help a bit in depth...I experimented with XR2206 f.generator driving VLF TX output. It was nice that i could easilly switch on any shape of signal with XR2206, so i noticed a bit better depth at square signal....Why is that so....i do not know?
There are things which should be experimented in "vivo"...cose many things put in simulator can misslead reallity....But best is to do both!

O.K. Geo...deal!
Regards!

[strujas]

PCB

Hello to everyone,, I made a pcb this is two layer board,,I have fixed eror around Q6,,,Here you can take a pcb and schematic,,if someone find some eror please to notice me ...I wish success to all of you in building this MD>..
Dimension of board is
X= 10cm
Y=9cm

[sisco]

I use PROTEL for design PCB and make PCB with this method :

http://www.dcc.uchile.cl/~peortega/ae/

and with this method making two layer PCB difficult for me.

can tell me what program use to design PCB.

thank

[strujas]

I am using Protel DXP 2004 ,,two layer board is more simple for making ,,you just need to use auto routing,,for one layer board I am working handly ,becouse if you set protel auto routing to one layer for complexly devices he cant do it ,,then I must to reconstruct everything manualy and thats really complicated..

[sisco]

I too (use Altum DXP 2004)


how you can convert pcb to pdf format ?

[strujas]

after you finsihed with routing ,,go to fabrication output final,,,when is new window opened go to print,,,,then chose for printer instead your printer adobe acrobat ,,,after that you just have to save file..
you need to instal full adobe acrobat.......

[sisco]

thank strujas

i use adobe reader ver 6 .this ver cann't make pdf printer.

i download in internet and use veryPDF mini EMF printer and this program can

make printer but after open final windows in DXP and print by veryPDF printer

convert to emf format .

which version of adobe reader can make printer ?