ElectroMagneticFieldAnomalyDetectors and nuts...

[ivconic]

Hi to all, and everybody are welcome here!
This is supposed to be a thread about a very interesting
effort to detect remote objects in the ground or at the
long distance.
No "mumble-jumble" involved.
I was "hooked" to start this thread by FrancoItaly's and
Esteban post's in the other thread:
"FrancoItaly:
Hi All
Look for theese link:
http://www.vlf.it/kurt/elf.html
http://www.vlf.it/Schumann/schumann.htm
http://www.vlf.it/below150/below150.htm
http://www.vlf.it/parmigiani-frozen/frlight.htm
A Ulf receiver with an E-field antenna it’s very similar to an
ion detector, it can receive Schumann frequency, it may be that
ground battery troubles Schumann signals?"

"Esteban:
Here a lot of interesting projects:
http://www.vlf.it/"
I would add that everybody look at GISCO EMFAD products first, on the .net
Look for GISCO EMFAD UG12 for example.
It is the fact that there are a "net" of distant VLF radio stations spread
all over the world.
"Electro Magnetic Field Anomaly Detector or EMFAD measures variations
in VLF radio electromagnetic field data caused by anomalies in the subsoil."
The system it self is receiving frequency range 44-142 kHz.
What can amateur like my self do about it?
Since this is a TECH forum, and since i am a TECH "freak", i simply can not
stand aside.I am too curious and want to build some device and try mentioned
principle.
For the first step i'll choose to make a receiver which is about to receive
those freqs. That receiver should have a very narrow angle of rx.It just
need to include a highly directional "antena". It will be only a first step.
.................
It is a start.
Waiting for reply...

[J_Player]

Hi Ivconic,

I agree, Franco showed us a fascinating study. I can't help much with designing a suitable reciever, but I am interested to see what you find at these frequencies that you are interested. I would hope that maybe you can find a way to demodulate some of these signals and see if they carry man-made information, or maybe only geophysical signals,

I will be waiting anxiously to see what you discover when you complete your reciever. Best of luck

[ivconic]

Yes, it is a good question.The truth is that it will need much more than just
an receiver.But as an amateur I can start from it, just for begining.In next 2-3 days I will prepare and post some simple schematics...
regards

[J_Player]

If you are highly skilled at building radio equipment then I would sugget that you build a sensitive reciever for the frequency bands that you are interested in, I would think the signal should be shielded and sent to a high-impedance amplifier, similar to the way the ion detector handled the signal. When you have the amplified signal, then you can add any stages you want to demodulate it or process the signal in other ways. It might be good to make provisions that will allow to adjust the bandwidth of the signall recieved as well as the frequency. I really don't have a clue for what kind of signal processing would be interesting to try.

I still think it would be good to attach an oscilloscope to the reciever so see the full spectrum of what you are picking up. If you have access to a small battery powered scope, then it would be good to connect it into the amplifier output and see what changes when you move the reciever to different locations.

[FrancoItaly]

HI All,

I have already explored VLF range from 500 Hz to 50 Khz with a self made receiver. It was formed by 2 orthogonal ferrite coils, a preamplifier stage, a VCF stage for tuning, a CC amplifier/rectifier stage and a push/retuning circuit similar to metal detectors with a meter/audio stage. I have noticed nothing of interesting as perhaps it was a B-field receiver and I think that only E-field can help us.

I intend to use the same VCF and retuning circuit with and high impedance stage in the range 3/30 Hz, with the purpose of avoiding 50 hz power line influence. I think it’s possible to measuring phase difference between 2 adiacent places by using a CD4046 as motion detector, it’s sufficient to use a time constant of many seconds in the low pass filter that drives VCO.

[ivconic]

I was busy last week....but since promised some ideas
here is a primer on main part of vlf/ulf receiver....
For the end i sugest a simple 10.7 IF from some radio
.....for example u can use some based on CA3089 or even
better on MC3357 or similar...3361,3371,3362,3359.....
even a simple transistor design would do a job.Further
analyze can be obtained,taking a part of signal from
later stage....(i am preparing some schematic on that).
For antena I would sugest a loopstick or even better
special design i am preparing and gonna post it soon.
You may experiment by winding 600-100 wind. of Cul 0.5mmm
on ferrite core, 30-45cm long and 3-6cm thick.
This is just an idea,I am very busy these days and off
.net so here is a little something just for a start.
regards....

[ivconic]

I have been tested UG 12/4 last few days.The aparatus seems to be
very usefull! I read manual many times and understood almost everything
,but one thing only.How to determine depth of the object.In the manual
that part was very "poor" covered! My friend Strujas scaned a gold coin (10gr)
from the surface of the ground. Gained result was more than good.Picture
in 2D and 3D is very clear and right.All measures of the presented
position of the coin were exact right!!! The only thing we can not
distinguish on the sight is depth of a coin.If i use recommended method
of how to determine depth,i get nonsence results like 1.07 meters or
simillar !!!!
As claims:" The approximate depth of an anomaly/object is determined by
means of calculating the so-called half value of a signal(geophysical
expression).......
And the "drag&click" method is explained further. When i used that
method the result was nonsence, like i said.
After all i noticed much more reliable method how to distinguish
relative depth.Simply an "eye" method.On the displayed 3D image,i can
see exact position and measures of a choosen profile respective to
the ground surface.Using presented measures i can find very relative
depth with 10-20% error, which in some cases is not a problem.But in
scanned image of some large area, error could be enormous!!!!
Therefore i am asking if someone already has such experience and can
explain me more, how to determine exact depth of a small object,scanned
with UG12/4.
Right now i am not in position to post some pictures here,but if somebody
interested i may do that in next few days.(i am using an ancient P-I now
without any possibilities to grab images from EMFAD Scan software, my dear
P-IV is at home and i am not!)
I would like to spread and grow this thread now, since, at last i discovered
a very usefull device for long(deep) range locating after so many years of
wasting time with trivial projects!!!!
waiting for some tips......

[ivconic]

I was absent a few days....a bit disapointed.....a low traffic here this days....
LRL threads are much more interesting(fairy tales are always...)
A real stuff is not...i guess.....well...that's life !
best regards!

[okantex]

Hi Ivconic,
what happened to your ULF .did you build it?
and I want to ask you something
is this emfad a magnometer?
it's software results look like okm's ,GEM's and accuratelocators'S imagers.
and for software ,you can download accurate locator's software from tehir page free.

[okantex]

and here info for dept determination.maybe it would be useful for you.
http://www.accuratelocators.com/pinpointer_card.html

[ivconic]

I am working on it,but it will take much time to be finished,cose there are a lot of problems to solve.
I am not satisfied with comercial models,to much questions unanswered yet...
We will see....
Thanks for the link.
When gain some progress i will post here everything...
regards