RELIC HAWK

[eclipse]

Question: Can I use normal inductor (bobine with 2 pins)
with 15mH inductance instead of the transformer?

[KingJL]

Hi,
I've made another discovery on RH clone...

That is: I can set it up to ignore ferrite rods and iron almost totally BUT in Disc mode only.... when I switch to all-metal it sings with everything... ferrite stuff included!

That's cause of phase shift... sure it is.

Now that's another puzzle... cause I expect that in all-metal I can get total ferrite ignoring... pure magnetic response... nothing conductive I mean but not! Dang ferrite gives sure some phase shifts there... I see it on scope.

So... still big troubles with coil and circuit...

Is the geb not working at all ? Look pretty strange or not ?

Max,
What is your oscillator frequency? You said it was low on the coil you made. The frequency has a great effect on the GB control. Example: at 5kHz the range of the phase shift for the GB control is 82 - 99 degrees (-8 to 9 around the 90 degree null); at 4.6K it is 89 - 105. If your frequency is below 4.5kHz you are above 90 degrees minimum setting and never be able to get below the 90 degree null point.

Before you determine that GB not working, I would get the frequency very close to the design target of 5kHz.

Regards,
J. L. King

[Fred]

Hi Max,

Is this result with the modified "F" point and did you try to configure the coil differently, to adjust shifting ?
regards!
Fred.

[eclipse]

I think there are still errors in version 1.8, MAX. According to me (and the schematic there) the generator should not work... Do you work on version newer than 1.8? Also there is written 26бр. which on bulgarian means 26 pcs x 100 nF - 2 capacitors on each IC? OMG sounds crazy, could it be

[Max]

another strange stuff...

Hi,
I've made another discovery on RH clone...

That is: I can set it up to ignore ferrite rods and iron almost totally BUT in Disc mode only.... when I switch to all-metal it sings with everything... ferrite stuff included!

That's cause of phase shift... sure it is.

Now that's another puzzle... cause I expect that in all-metal I can get total ferrite ignoring... pure magnetic response... nothing conductive I mean but not! Dang ferrite gives sure some phase shifts there... I see it on scope.

So... still big troubles with coil and circuit...

Is the geb not working at all ? Look pretty strange or not ?

And the trouble is now... how to simulate ground conditions without magnetic minerals (so no phase shifts) to be sure geb actually works ???

A puzzle into a puzzle...

Kind regards,
Max

[amtech2005]

RELIC HAWK

Hello Forum
Good news:19hours to release Minelab RH $200

http://cgi.ebay.com/MINELAB-Relic-HAwk_W0QQitemZ280241608644QQihZ018QQcategoryZ14955QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

We can have it to see real circuit schematic!!!if somebody of the forum live in USA and can buy it for me (carl?)and for us(the Forum) , i will send money via western Union.
Alexis

Alexmex , Did you know the buyer ? The winning price was $331.79. A very good price with a total 13 bids. It went to a German Technician. So if he knows this forum we will have good news to correct a bad schematic. If not , we will still have a corrected schematic and a great project to build !!! So a very,very good price considering the new mfg. list price was $1295.00 back around 2002 or so....just wanted to post the results before we all forgot!!!........Take care everyone.....Eugene

[Max]

However you want to do it, but the output at u6 pin 1 is at cmos compatible level, < +- 5.5V (actually it is about 5-6 vpp).

Regards,
J. L. King

Hi JL,
well as about maximum ratings it's true...4024 is 3-15V device but can run on 18V if required, with few limitation at inputs but you have to consider that a logic "zero" is anything below 2V and a logic "one" is anything above 3V... this is the typical situation for 4024 input levels...

So the direct connection will work only if the output voltage will exced both levels up and down, with voltage level from under 2V to over 3V typically.

Now , actually, this is possible but not forced by design... so if U6 pin 1 output voltage will change in way the above condition is not matched then it will not work. That's why is always better having a true level shifter there.

Kind regards,
Max

[KingJL]

You actually don't know which voltage there is at pin1 of U6... cause depends on TX coil voltage... but it's really difficault you get there a CMOS compatible level of voltages... so it's like playing dice there... sometimes could work... but it's unreliable unless you pay attention on that voltage... if don't use a level shifter etc

So, the actually made the easy way: used a comparator that acts as level shifter and it's triggered at zero crossing. This is a truly safe way of doing it.

However you want to do it, but the output at u6 pin 1 is at cmos compatible level, < +- 5.5V (actually it is about 5-6 vpp).

Regards,
J. L. King

[nakky]

Hi Max,Ivconics RH LIGHT from 4024/1 to lm393/7 to 4066/13.Grt Nakky.

[Max]

I agree. But since you are going to move the souce of 'f', why not source it from U6 pin 1? That way no changes to GEB or DISC will have an affect.

Regards,
J. L. King

Hi,
yes, good observation... but you probably forget a thing... I think ML put the line there cause of a reason:
do not interfere much with true signal path and give compatible signals where required

Let me explain... I think that if you bind the "f" there... so connect the pin1 of 4024 with pin1 of U6 you'll get troubles...

Why ? Simple, the 4024 expect a CMOS input level there.

You actually don't know which voltage there is at pin1 of U6... cause depends on TX coil voltage... but it's really difficault you get there a CMOS compatible level of voltages... so it's like playing dice there... sometimes could work... but it's unreliable unless you pay attention on that voltage... if don't use a level shifter etc

So, the actually made the easy way: used a comparator that acts as level shifter and it's triggered at zero crossing. This is a truly safe way of doing it.

Kind regards,
Max

[KingJL]

My conclusion is... people who made the bulgarian schematic on page1 know about the exact connection of the "f" line, so they followed that scheme. People who made the complete schematic probably don't know or mistaken about the "f" line connection... or intentionally faked schematic there. I don't belive ML could have made such a stupid mistake connecting the "f" at disc control signal.

What do you think ?

I agree. But since you are going to move the souce of 'f', why not source it from U6 pin 1? That way no changes to GEB or DISC will have an affect.

Regards,
J. L. King

[Max]

the &quot;f&quot; line...and detector behaviour

Hi,
this post to explain what I realized from getting the "f" from the geb control signal:

detector is more quiet...than before...

Also, before I made that change the movements on disc pot, even in all-metal mode, gave variations in random chatters and the like...

Now what I think:
have no sense to me using the disc path to get the "f" signal... cause the disc pot rotation change the phase of that signal respect to the transmit signal at TX coil, that's reference.
Have much more sense to me that the "f" is get from geb path, instead, cause once you tuned device on soil you'll not touch the knob anymore, unless you change soil (e.g. move far apart in the field, that require new geb fine tuning): this is expecially true when using disc mode... where you're expected to move the disc pot... thus resulting , as in schematic we follow, in a variation of the phase at every disc pot movement that could imbalance detector and cause erratic behaviour.

My conclusion is... people who made the bulgarian schematic on page1 know about the exact connection of the "f" line, so they followed that scheme. People who made the complete schematic probably don't know or mistaken about the "f" line connection... or intentionally faked schematic there. I don't belive ML could have made such a stupid mistake connecting the "f" at disc control signal.

What do you think ?

Kind regards,
Max

[Max]

I think that oscilator will be much stable if you use 2n4401 and 2n4403 instead bc237 and bc337
Regards

Hi,
thanks for the hints... I haven't them handy... but if could find some I will try.

Kind regards,
Max

[strujas]

I think that oscilator will be much stable if you use 2n4401 and 2n4403 instead bc237 and bc337
Regards

[Fred]

Hi,
I've spotted another difference between this (complete?) schematic and the bulgarian version called "relic hawk I", look at "f" point... that goes to pin1 of 4024...

don't you notice anything different ???

The 4024 gets its clock from geb/all-metal control signal, but in our RH schematic the "f" is at disc gate control signal...

So... someone could say... ok , it's always 5Khz there...

Sure... but I don't think is the same getting clock at 90° more or less ? Do you ?

In an extraordinary hi gain device...like THIS IS... that 90° could make lot of differences...

Kind regards,
Max

Well done Max,
This is an interesting difference,mostly with he discrimination problem .You just have to connect F to pin 6 instead of 5 of 4066.
BTW, the bulgarian version pin7 of 4066 is wrong, should be 8.
regards,
Fred.