RELIC HAWK

[Max]

Hi Max,

This is very interesting, thanks !
Nice that you have found it.It is not so easy.
I made a new modifications to the PCB , according to your founds : a ground plane.
This bring several vantages ,for the decoupling caps in particular.
I dont think we can consider anymore a single layer as an easy option anyway, but it still should be possible.
With this groundplane it will give more work to do the clearance hole for components, but many of them will be grounded on each side.I also could have removed some "copper side" traces, as they were not needed, but i didn´t , this was not really necessary and will still allow a single side design.

Let me know what you think about this,it looks confusing at first because of the different colours but if you remove layers you can see it better.Also print preview works well.

Your results looks good, 26cm with a not completely optimised design is nice.

Please continue the good work!
Keep dreaming

Regards,
Fred.

PS: updated for better GP

Hi Fred,
good news... I like the idea. I think would reduce problems there.

I've mounted the caps on bottom side... using a kind of mesh made by a rigid 0.5 tin plated copper wire... flying assembly! Ugly enough...but of course it works, that's important.

Used polyester caps 100nF 63V for everything... but ceramics are nice too there... used them cause have more rigid structure this way.

Made also some holes in PCB to hold screws etc to avoid pcb stay on the soldered mesh of wire.

Kind regards,
Max

[Max]

I am just a little upset today !!! So Thanks Fred and Max for your hard work and Dedication Here !!!! When this project is completed it will be better than the original !!! That is why this Relic Hawk is discontinued because it did have problems in the field. Remember what another member said here about a month ago , about the Relic Hawk working good only with only certain ground or surface condition's ??? Sometimes companies throw out models too fast , one after the other , without field testing enough !!!!!!!! And then you read about problems in the field . And that's why this " FORUM" has modification posting's all the time. And also people are alway's asking how to make their detector better !!!! And they are the one's that overpaid several hundred dollars for their detector and got very dissapointed when they were out in the field !!So all the metal detector manufacturers around the world "with their 10 models or more for each company" being manufactured .Why so many models ??? So the Detector manufacturers sould not Complain Here ever but "LEARN FROM US " !!!! . I am sick and tired of Detector companies that mislead Everyone and say "TOP OF THE LINE". Top of the line in what catagory?? I am not here to slander anyone . So Carl is welcome to delete this post if needed . Many people work hard for a living and when they go out and spend $600.00 or $700.00 for that advertised "Best Detector" and get only 60% depth of a "Real Top Of The Line Unit " , Yes, Something is definitely Wrong with the detector industry !!!!!!!!!!! This post is MY Opinion , Thanks for reading , .....................So to me "THE MAIN PURPOSE OF THIS FORUM IS TO BUILD A GREAT DETECTOR AT A REASONABLE PRICE OR FIX THE DETECTOR THAT WAS OVER PRICED by SEVERAL HUNDRED DOLLARS"!!!!!!!!!.............Eugene.

Hi Eugene,
don't know about why ML retired the RelicHawk, maybe you are right on soil conditions effects... I know it was very powerful and stable device in average/low mineralized soil.

I think the problem with so many models is that big companies wanna sell as much as they can... so they do same way e.g. food industry do: a single company can make 20 different kind of peanuts butter just to fit , with each "recipe" and "taste" , every market hole, even the smallest, otherwise someone else will fill that empty hole instead of that company.

Same stuff: why most manifacturers made VLFs, PIs for military, TH, industry etc etc... so much and different stuff ??? They wanna cover every needs from fancy to the more sophisticated, and lock on the market in a top position. That's capitalism essence I think.

Now , the problem is... with peanut butter one would spend 1-2$ more to try the different taste of some particular preparation... then maybe one could drop all in the trash can if the taste is worse... but with MDs.... that costs thousand dollars is a real shame one spend so much money for a bad taste.

That's why I suggest people here trying stuff before buy on dealer's test gardens... cause after buy discoveries are almost always delusions and troublesome situations...

I also don't like bad advertising on products... top of the line, best ever... and similar stuff: for me ads should provide useful informations... but as with other products, ads are made following marketing principles... not technical issues... and from this fact problems grows till disappointed users just sell devices and found another hobby!

Paradoxes...but the fact is also for one that leave... others will arrive and buy... and all manifacturers well know that and play with customers.

Kind regards,
Max

[nakky]

Hi Max,U13 point 1 f to U3 point 5 f thats oke but U13 point 11 f/4 were dit this going to?Grt Nakky.

[Max]

Hi Max,U13 point 1 f to U3 point 5 f thats oke but U13 point 11 f/4 were dit this going to?Grt Nakky.

Hi Nakky,
it goes to pin9 of U12 (4053, multiplexer).

It's 1.25Khz audio tone used by audio stage.

Kind regards,
Max

[Max]

Hi,
another little mistake found: 27K for 22K at unity gain inverter.

Changed to 22K.

Kind regards,
Max

[nakky]

Thanks Max,yes I can see that line in schematic,but f/4 make me confused.Grt Nakky.

[Max]

Thanks Max,yes I can see that line in schematic,but f/4 make me confused.Grt Nakky.

Hi,
very easy: the 4024 is 7-bit ripple counter, at pin11 you are at output of second stage... so you divide frequency by 2*2 = 4, then RH uses that frequency for audio part.

Kind regards,
Max

[nakky]

Very easy for you but not for me.Grt Nakky.

[nakky]

I don't understand it but try to copy it.Grt Nakky.

[Fred]

Hi,
another little mistake found: 27K for 22K at unity gain inverter.

Changed to 22K.

Kind regards,
Max

Ok, i mistaken with other resistor.Twice...
regards,
Fred.

[Max]

Hi,
still have lot of instability in disc mode: device gives always a beep beep at variable frequency when I turn geb pot...

Don't know what's going on but seems self oscillations present...

In all-metal it works somehow like described above... about stable and with medium detection range on 1eur

Kind regards,
Max

[Fred]

Hi,
still have lot of instability in disc mode: device gives always a beep beep at variable frequency when I turn geb pot...

Don't know what's going on but seems self oscillations present...

In all-metal it works somehow like described above... about stable and with medium detection range on 1eur

Kind regards,
Max

Hi Max,
the variable frequency thing is very strange.Are you sure the 4066 is good? i have seen problems with those Cmos, sometimes gates just works weird.
Could it be that you are amplifing an harmonic? when sound is variating, is that progressive or jump one octave?
I wish i have my IC´s...but it will still take a some days for them to arrive.
I think i will make a new PCB with the mods and ground plane.There is less than 50% comonents on mine,so it is still time.

Regards!
Fred.

[Max]

Hi Max,
the variable frequency thing is very strange.Are you sure the 4066 is good? i have seen problems with those Cmos, sometimes gates just works weird.
Could it be that you are amplifing an harmonic? when sound is variating, is that progressive or jump one octave?
I wish i have my IC´s...but it will still take a some days for them to arrive.
I think i will make a new PCB with the mods and ground plane.There is less than 50% comonents on mine,so it is still time.

Regards!
Fred.

Hi,
no I think 4066 are ok: all brand new parts , genuine motorola mc14066

I noticed that moving both fixed geb trimpot (when on fixed on the switch) or the manual pot I get same behaviour... device change the beep frequency from 1Hz to some 3-4Hz... rapid beeps.

I see it also on the scope... the output of U7 goes up and down. At first I had a thought about speaker influence... but it isn't... I disconnected the 16ohm speaker and found same story: output goes up and down, locked in self oscillations at extremely low frequency.

I found a 250Khz harmonic down the path but it's extremely low amplitude... so it's sure not involved in that.

Don't know what to try now... maybe I would better try with tarots...and the pendulum stuff... like remote sensing folks do everyday!

Kind regards,
Max

[amtech2005]

Relic Hawk

Max , I was digging through the Geotech Archives again yesterday , I read a few comment's that were made about minelab coil's and also transistor's. Just wanted to mention a few thing's . Did the standard 8 inch minelab coil have an exact 1.014 millihenry inductance for tx , not 1.0 millihenry ???? Also is capacitor measured on tx circuit 0.6 micro-farad's ??? And finally transistors were not BC series but 2 number's were mentioned a C33740-ph90 and TR51-ph7 ???? I am checking now what they are . If this help's Great !!! If not then it's Just some assorted garbage I read yesterday...........Have a Good week !!!!!!..........Eugene

[DIRCEU]

Hi,
still have lot of instability in disc mode: device gives always a beep beep at variable frequency when I turn geb pot...

Don't know what's going on but seems self oscillations present...

In all-metal it works somehow like described above... about stable and with medium detection range on 1eur

Kind regards,
Max

HI! MAX

What coil do you using on RH project??

Regards

DIRCEU