VLF MD (by Sascho - Varna)

[Max]

"..the problem is to couple the ultrasound to the ground..."

Indeed! This will be the main problem! In hospital, they used sort of gell...
On soil..????
Good point!

Hi,
I remember that Carl-NC already gave hints about this topic to Sharky: he suggested using some tons of PEANUT-BUTTER !

But Sharky was already under drugs at that time... so used gelled LSD instead!

Kind regards,
Max

[Max]

I just wanted to point on mistake he made cose testing coils without shields....

I am so so... yesterday i was under doppler, examined my liver. Well liver is fine, but i do have 2cm "rolling" stone in my gall-bladder, causing me a lot of pains. Damn. Need to wait for some time and than operate it. I was thinking to totally remove whole gall-bladder, not only stone. Further it will solve all problems. I can drink and eat what ever i want without extra precautions.
I will see...
But i am not telling this without reason;
while lying under doppler i payed attention on it and examined it carefully.
A strange idea occured to my mind; can we make diy doppler and try to use it in prospecting??? Ha?
Skin,organs and bones tissues are closely than many soils i do know. How come that tiny ultrasound can penetrate tissues and can not soil?
Is there anybody,ever tried or experimented with doppler so far?
This question can look pretty naive...but hey, what do i know? I never had any experiences with it so far...
Any experiences?

Hi,
I hope you will free of that rolling stone soon... to come back on prospecting man! And of, course, do great work on building stuff here... you are a number one constructor here ! (I use this term to distinguish you from sunday's homebrewers).

So , take it easy for now, and relax... and , of course, I offer my wishes for all good things about your health.

About ultrasound, well I was thinking at it from years now... maybe 15years... don't remember... but had a similar experience in a hospital, saw machine there and take lot of thoughts about expecially sensors (the thing they move above the gel stuff).

But I noticed really easy the problem at interface... ultrasound need perfect coupling with medium that need investigations... so you cannot use them as they are from e.g. some ultrasound diffusor out... on the air ... they will bounce back at soil... no good interface there for that frequencies.

Better would be some microwave thing... the kind used in GPR but seem complex issue for an homemade device.

Also GPRs require extra care and special handling ...logging etc... very professional but not for anyone.

I think ultrasound is not good for TH devices, too complex approach and results will be always under e.g. ability of GPRs.

Kind regards,
Max

[ivconic]

Thanks Max,
yes i did some "research" today and really; coupling with soil would be a huge problem. Usually soil is not consistent, number of small cavities.Big problem.
Maybe it can be done on leveled,consistent surfaces, cave walls etc..
Need to be explored..

[Leto]

Hi,
Leto.
Thanks.So I will try 19,5cm former TX=100w 50/25/25 and RX=100w wire 0,30 mm.
But still cant trace scheme and see where to place what.
Have you changed the places of TX points or they are like on scheme?
Pleace give one closer picture on finished PCB.
I am almost ready to begin soldering elements.
Can I replace LM2930-8 with 7808 arent they the same?
For transistors near TX I should use 2N2907 right?What about other 3?
And we have 1N4001 and 1N4148 for VCO and whats the other one 1N4001?
I still cant understand what change have you make from the look on the PCB that we have to make it work?You have mooved one resistor but which?
I have to now so I can make changes now?
How did you null this coil?
Thanks
Onece again EXELENT work!!!!
I cant understand why Sasho don't post here?
Maybe he isn't avelable now?
Last year he have helped here dayly.
I am curies how much diferent is nexus actuly?Maybe in some values.

LM2930-8 is LDO voltage regulator, you can replace it with ordinary but keep battery above 10 volts.
I used 9V regulator and 12V battery as I did not had 8v regulator.
Try with 3k resistor (on picture disconnected 3k3) in place and measure +- voltages in respect to ground.
About transistors read post#14, there are two 1N4001.. Pairs of red 470nF capacitators are connected in parallel to get two 1uF.
Nulling is simple but discrimination/GEB will not work if coils are not well nulled.
Try to use 10nF resonant cap across Tx output (see picture).. to get oscillation.
I'm leaving home and this forum for couple of weeks but I'm sure you will figure it out..
..and yes Tx points on PCB are not in same order as on shematics.

[ivconic]

Hey Leto, i envy you on such nice photos. Can you explain me how are you managing to take such nice and clean photos?
I do have Praktica 2.1mpix (older one), and it has possibility to make nice photos also. What do i need to settle to take such nice photos, to be posted here later...
Thanks in advance.

[tiktak]

hi

Hi,
Thanks Leto.
So I will also use BC107 and BC177 and BC517.
But still cant understand how did you null coils?
With the value of that missing cap?
And where you solder this 3K resistor?
I am almost ready with the PCB will finish and test soon.
Its sad that when you shield this TEST coil the device is not working,but its probaly something missing.I am shore that this will be very good machine!
This is one of the hidden sashos best designs.!
He told us that this is very similar to NEXUS there is some trik in coil that we still dont now but........with so many minds here this wont be secret for much longer.

See you soon

p.s.what is this 650mA scale?I see that you use scale from old multimeter I think?

[Unregistered]

To N@sko
Bobinite se ekranirat.Na mestata kadeto se presi4at ekranite se isolira.Sled tova se namira polojenieto im pri koeto ima minimalen signal v priemnata bobina.Kompensirastia kondensator ne e vklu4en.V tova polojenie se zalivat sas epoksidna smola.Sled vtwardawaneto i se kompensira dat4ika 4rez podbor na kondenzator mejdu oszilatora i priemnika.Pri tozi Q faktor
i niska 4estota dat4ika e mnogo stabilen vav wremato.Stabilnostta e po wisoka otkolkoto
pri kompesirane po faza i amplituda.Pi6a ti na balgarski za6toto sam mnogo zle s angliiskia.
Kato iskat da nau4at ne6to da u4at balgarski.Ne sme po prosti ot drugite. Pozdravi.
Sascho-bg

[ivconic]

"...Kato iskat da nau4at ne6to da u4at balgarski.Ne sme po prosti ot drugite..."

Ha,ha,ha,ha!!!

[gordianus]

ok

golegi

[Geo]

To N@sko
Bobinite se ekranirat.Na mestata kadeto se presi4at ekranite se isolira.Sled tova se namira polojenieto im pri koeto ima minimalen signal v priemnata bobina.Kompensirastia kondensator ne e vklu4en.V tova polojenie se zalivat sas epoksidna smola.Sled vtwardawaneto i se kompensira dat4ika 4rez podbor na kondenzator mejdu oszilatora i priemnika.Pri tozi Q faktor
i niska 4estota dat4ika e mnogo stabilen vav wremato.Stabilnostta e po wisoka otkolkoto
pri kompesirane po faza i amplituda.Pi6a ti na balgarski za6toto sam mnogo zle s angliiskia.
Kato iskat da nau4at ne6to da u4at balgarski.Ne sme po prosti ot drugite. Pozdravi.
Sascho-bg

Please can you translate it to English??

[gordianus]

pomos

golegi mislya da prava tazi grozdanka no kata gledam na shemata nesa napisani nakoyı elementi bihtelimi pratili dobrata shema blagodara [email protected] saso pomos

[Leto]

tiktak,
Take care on transistor pins - using 2N2907 for TX will need some twisting of terminals - check this twice!! Board is designed for TO220,225 TX transistor packs.
There is no missing cap -> I place resonant capacitators in the search-head near coils. 10nf is just proposed value you can fine-adjust it later.
If you succeeded with nulling TGS coils than this one will be easy. But making good balanced LC cross-coupled autotransformer coils is another story .. specially if you want durable results.
I shielded the new coils - very good results, still have to encapsulate them in the search-head and do the field-testing.

Ivconic,
I have one photo hint - you need more light on the subject. Maybe you should try it during daytime once - I'm sure your 2.1Mpix will then perform much better.

I wonder if this thread was a mistake? Not much usefull but for DOWNLOADING and some slavic gibberish. In my "free"-time last three months, lyin in bed, I designed many PCB boards like this one above: INCA, GSdip, newTSS+, SaschosPI, and few unfinished but all untested and there is great demand for new projects (and old), but PCBs remain secret - WHY?

[tiktak]

Hi,

Hi,
Leto.
Thanks.
I am shore that I will mess something so I will post tomorow pictures with labeled elemens and pins so it will be easyer for all.!
And with some revision from you the things will be clear.!
What are the results with this new coil?
What is this 10n resonant cap?I never herd such and I am almost shore that I wont be able to find it here.So how can I replace this?With normal 10n?

And one more thing where should I solder this 3k resistor,desoldered pin on last picture?

I have nulled TGS coil,but I now from the begining where to atach what and measure what.But here there are no data!So please tell me how you null?
Pin 7 5532?

[tiktak]

Hi,

Hi,
Leto.
Because you help me much and I now that you wanna now what sasho is telling to you with his last post here is translation:
To N@sko
Bobinite se ekranirat.Na mestata kadeto se presi4at ekranite se isolira.Sled tova se namira polojenieto im pri koeto ima minimalen signal v priemnata bobina.Kompensirastia kondensator ne e vklu4en.V tova polojenie se zalivat sas epoksidna smola.Sled vtwardawaneto i se kompensira dat4ika 4rez podbor na kondenzator mejdu oszilatora i priemnika.Pri tozi Q faktor
i niska 4estota dat4ika e mnogo stabilen vav wremato.Stabilnostta e po wisoka otkolkoto
pri kompesirane po faza i amplituda.Pi6a ti na balgarski za6toto sam mnogo zle s angliiskia.
Kato iskat da nau4at ne6to da u4at balgarski.Ne sme po prosti ot drugite. Pozdravi.
Sascho-bg

To N@sko
The windings have to be shielded.On the places where they cross should be isolated.Then they have to be placed such way that there is minimum signal in RX winding.The compensaiting capacitator is not inclouded at this time.In this position they have to be sealed with epoxy.Afther the epoxy is hardened the /indicator/ is compensated with right choice for capacitator between oscilator and reciver.With this Q factor
and low frequency the /indicator/ is very stabile in time.The stability is higher
than compensated for faze and amplitude.I write in Bulgarian because I am very bad with English.
If they wanna learn something they should learn Bulgaian.We arent more stupid than the others.Greetings.
Sascho-bg

[N@SKO]

Sasho blagodarq ti mnogo za informaciqta!
V na4aloto misleh da slagam potenciometur za fazata i amplitudata za6toto ma6inite ot tozi tip s koito sum rabotil bqha mnogo tempreraturno nestabilni.Kondenzatora v prevatelnata namotka nqma da go montiram
v glawata v takuv slu4ai.Za ekran smqtam da izpolzvam folio,no kak
da napravq vruzkata s masata?Vijdal sum napravena vruzka ot nqkolko namotki na kup v/u folioto i sled tova zalqti s kalai ili kakto pri magnuma
da namotaq celiq ekran s kalaidisan provodnik samo 4e neznam s kakva stupka?Kakvo e predlojenie za nai dobur ekran?
I posleden vuprosTrqbva li da slagam kondenzator(m/u kolektorite na tranzistorite) kakto Leto za da raboti generatora?Ili prosto e nujen kogato
usilvaneto na tranzistorite e po malko ot 200.Pozdravi.