RELIC HAWK

[Max]

Hi,
I will try!I were thinking that the frequency is set buy number of windings.Now I get your idea.
Thanks

Hi,
yes it's so... but if you change the shape of boundle you change inductance... so also frequency.

But just few hundreds Hz most of the times.

Kind regards,
Max

[tiktak]

Hi,

Hi,
Max.
But if so there is no metter what is exact frequency.In this case.
What shel i try to fix the phase shift?

[Max]

Hi,
Max.
But if so there is no metter what is exact frequency.In this case.
What shel i try to fix the phase shift?

Hi,
no... well... if you made on a particular shape former... you already know wich would be the end frequency once on the housing... just little variations.

That's like TGS coils... you use a particular former... and not change much the shape of the halve... that way you get about the frequency required every time you made a new one.

Sure, if you change much the shape you'll change also frequency more and more... usually is not a big problem once you have exact number of turns and shape of former... you need just little adjustments to get it work.

About phase shift... in the near of absolute nulling (zero) you'll get many different angles; things start to complicate when you need a particular phase shift between tx and rx but to reach it you outnull the coil too much: too residual voltage is a bad sideeffect cause then, due to hi amplification and ground effect, you could experience saturation of op amp chain...no good.

The best is find a good null (low residual voltage) and required phase shift: that coil is the PERFECT coil for VLF, cause have everything needed to deal good with mineralization and disc issues.

Sometimes some coils are not easy to null good at right phase... then one will simply discard them and make others... no easy solution: due mainly to thickness of bundles and lateral flux chaining.

Kind regards,
Max

[Fred]

BTW,to get a better nulling i had the idea to make a coil with wires passing inside of each other.This way a "perfect" nulling could be achieved.
What do you think ?
Regards,
Fred.

[Max]

BTW,to get a better nulling i had the idea to make a coil with wires passing inside of each other.This way a "perfect" nulling could be achieved.
What do you think ?
Regards,
Fred.

Hi,
I think it's the way of Nexus' coils... but seems hard to do... cause make chained windings is not so easy without some particular former I think...

Also it could be easy with round coils... but on DD is even more complicated.

Anyway, the idea is interesting... who knows... maybe in the future someone will find some good strategy to wind easy this way.

Kind regards,
Max

[Fred]

Hi,
I think it's the way of Nexus' coils... but seems hard to do... cause make chained windings is not so easy without some particular former I think...

Also it could be easy with round coils... but on DD is even more complicated.

Anyway, the idea is interesting... who knows... maybe in the future someone will find some good strategy to wind easy this way.

Kind regards,
Max

Hi Max, doesn´t look so dificult :just wind the first coil the usual way.Then Put it perpendicular and tape it to the board ,then wind the other coil passing your new wire inside it.As long as the coil holding your new wire is small enought to pass inside, that is almost the same work than doing separate coils..i think
Regards,
Fred.

[Max]

Hi Max, doesn´t look so dificult :just wind the first coil the usual way.Then Put it perpendicular and tape it to the board ,then wind the other coil passing your new wire inside it.As long as the coil holding your new wire is small enought to pass inside, that is almost the same work than doing separate coils..i think
Regards,
Fred.

Hi,
yes, that's the way I thought too... using a small reel that will pass inside the first coil...

additional problems are at shielding... you e.g. shield first coil before wound second, but then you'll have to shield second when both are chained... tricky but possible.

I think it will require some 3-4 the time I usually do simple coils.

Kind regards,
Max

[Fred]

Hi,
yes, that's the way I thought too... using a small reel that will pass inside the first coil...

additional problems are at shielding... you e.g. shield first coil before wound second, but then you'll have to shield second when both are chained... tricky but possible.

I think it will require some 3-4 the time I usually do simple coils.

Kind regards,
Max

Ok Max,
That would be interesting to try.I use copper tape for shielding, so again not too dificult to tape it . can be done befor or after winding i suppose...the question is if it will really improve it or not.
One more experiment for Winter days
Regards,
Fred.

[Eugene52]

RELIC HAWK

Around the end of this year or at the begining of the new year my goal is to finish this Relic Hawk circuit and post oscilloscope photos of all test points. The Relic Hawk oscillator circuit is a strange design and has me a little confused , maybe it is not so stable and thats why minelab discontinued it !!! I will succeed in completing this project , I always do and will enjoy the challenge.....................Eugene

[Max]

last schematic revision (2.0) , reposted here

Hi,
here is again last schematic revision 2.0.

It works. I think no mistakes anymore on this...

Kind regards,
Max

[Fred]

I will post the last version of PCB today. It would be great if ivconic could make it, as he owns the original coil and with oscilloscope, could tell how it works with it.
Nights are becoming longer and soon i will continue mine.Probably when hours change
Regards,
Fred.

[Max]

I will post the last version of PCB today. It would be great if ivconic could make it, as he owns the original coil and with oscilloscope, could tell how it works with it.
Nights are becoming longer and soon i will continue mine.Probably when hours change
Regards,
Fred.

Hi,
I've put aside some TGS stuff I'm doing at now to focus again on RH, that's indeed a good project I think.

Now connected the board again and watching at scope seems everything like last time I checked it.

I have to say to people who wanna try the pcb design that extra care is needed on decoupling capacitors. I added them on bottom side using a flying strategy like in some old RF stuff... the ones where components are suspended by solder joints... in doing that I was really careful not to add a closed ground loop, truly essential when going for good performances and lowest noise.

I think the more people will join RH thread... the more will gain a good device soon, cause just minor refinements required.

Kind regards,
Max

[Fred]

Here is last RH PCB for Sprint layout 5.
I don´t think there is much difference from this one and the last one posted here,but i am not sure.
Regards,
Fred.

[aft_72005]

Hi Max and Fred
I am hope help you. Other circuit, it had nice draw.
Best regards.

[Eugene52]

RELIC HAWK

AFT_72005 , Nice schematic you posted . Dated today !! Where did you find this one , and is it correct ????................ regards.........................Eugene