Cable locator

[Davor]

Funfinder, many of your points are very legitimate, and as for the usability... think of large caches of bronze age.

Some meters deep - by unreliable longwave-ground waves or better by the vertical magnetical component of them?

Highly unprobable. Especially in regions with hills or mountains and even more questionable if the site is full with all kind of junk.

30kHz wave has 10km wavelength, hence Mt. Everest is of little significance. Ground waves are attenuated proportional to distance and frequency, so they are not very well known in SW and above, but they are very real in LF. Ground wave field is deformed around conductive objects (and non-conductive voids) and that's it. It can't get any simpler than that.

[bernte_one]

hello

i am on the way to build one
just waiting for my new sprint layout 6
so that i can adapt the pictures from the book to a layout file

the theory is good described in the book also some basical formulas for for calculating L, C and F with examples
i think its not wrong to look left and right

at moment too many mosquito for detecting
so why not spent some hours for proof a concept

[Funfinder]

@ Qiaozhi

> This has nothing to do with LRLs.


Please stop criticizing or correcting me - and how can you say it has nothing to do?

LRL is not LRL - of course! We have the complete nonworking pseudo-esoterical random-beep or ideomotoric swivel around crap - BUT:
we also have those passive longwave ferrite antenna magnetic-anomalies PDK stuff incl. Mineoro and OKM which also are commercial products.
So commercial product means nothing as long as its not really proven tested under what circumstances and how serious it works or not.

Both are using: long wave, ferrite antenna for magnetic field reception, some kind of meter to detect anomalies
simple spoken: its completly the same technic priniciple !

And pipe also is not pipe. If the pipe is metal, 30cm diameter and 1m deep a good metal-detecor will find it much better.

But if the pipe is made of concrete and for sewer, 50cm diameter and 5m deep those "radio-detectors" for shure won't find it.
And buried cables also can vary alot.

Where are the proven tests for those oh so nice radio-pseudo-detectors?

I have the data here from the Leica_Digicat_500i_550i_UserManual_780598.pdf

Page 74 transmitter:
induction mode 150m / 490ft
connection mode 250m / 820ft

depth:
Power mode: cable gets feeded with EM-signal directly - up to 3m (for shure only at non mineralized soil)
Radio mode: some radio station is used - up to 2m (perhaps just for 2m thick iron-pipes or 2m large concrete tunnels)
Transmitter mode: if the transmitter is close nearby - up to 3m (same situation as radio mode - huge objects are needed for such depth)

This means if the transmitter is on, the detector will locate the stuff around 150m "wireless" or 250m if the pipe has direct contact to the transmitters antenna.
perhaps this transmitter uses some 200mW or something.
But this is a huge difference as some very weak far away radio stations.





@ Davor
> think of large caches of bronze age.

Nice picture , but the reality looks different. There are no bronze age caches buried every 50 meters and 3m deep.
They are more likely extremly seldom and buried just 50cm-1m down.
And I have a big problem with the usual describtion of "ground wave":

The transmitter is aerial and not ground, and if a little 10cm ferrite antenna receives a small magnetical part of the 10km large longwave-lenght
then first it receives this signal not in ground but still in air (just close to the ground) and second there is a very huge chance for all kind of distortions.

You also know that radio-waves are sensitive to all kind of reflections, they can add to themselves or they can be very weak if there is a shadowing object
like a mountain and the thinking that radio waves will go directly through hills and mountains, water, see and buildings also is wrong.


Of course the principle works for detection, but only if the field strenght is good enough.
The strenght of this german time pulse signal not just is much too weak outside of Germany but also it uses special modulation which makes
detection even more critical as if it would be a signal that always provides the same EM-field strenght.


> Ground wave field is deformed around conductive objects (and non-conductive voids) and that's it.

Yes, and thats the problem - it will also be deformed by mineralized soil, changes of humidity, thickness of the soil until bedrock, inside a wood, near rivers and of course by close to the surface conductive other metal objects. AND: when the ferrite antenna's angle slighty shifts or the ground distance changes while walking the signal-level also will change.

Seen from the principle this is like magnetometer because it doesn't matter if some longwave signal produces a magnetical field strengh or the earths magnetical poles.

And there is a high chance for errors if that LW-receiver does not use 2 different ferrite-antenna circuits - same with a simple magnetometer - the magnetical field may
change, but this can have alot reasons.

[Funfinder]

Here you can see the EMFAD circuit, also such a LW-detector. Seems its not complete, some info including the antenna is missing.
I would say this is a simple AMP & signal compare circuit. The 'voltage detector circuit' signalizes if the batteries are still full enough.

http://www.geotech1.com/forums/showt...627#post175627

L1 (seems to be the only one and probably the ferrite-coil) has written 7 - 26n or 26m - 7r - perhaps it means 26milli-Henry inductivity.
Its together with C6, 10nF which works for the longwave range. But wheres the ready analyzed signal output - by speaker or whatever?

[Qiaozhi]

LRL is not LRL - of course! We have the complete nonworking pseudo-esoterical random-beep or ideomotoric swivel around crap - BUT: we also have those passive longwave ferrite antenna magnetic-anomalies PDK stuff incl. Mineoro and OKM which also are commercial products.
So commercial product means nothing as long as its not really proven tested under what circumstances and how serious it works or not.

Both are using: long wave, ferrite antenna for magnetic field reception, some kind of meter to detect anomalies
simple spoken: its completly the same technic priniciple !

I think you're getting a little confused here.

The "nonworking pseudo-esoterical random-beep or ideomotoric swivel around crap" (as you put it) is exactly that. I agree! And ... by referring to LRLs, I was also including the "passive longwave ferrite antenna magnetic-anomalies PDK stuff". Why do you think we don't discuss these devices here on Geotech? All the LRL stuff is over on the Long Range Locators Forum.

The book that is being referred to in this thread has absolutely nothing to do with LRLs of any kind, whether it is the swivel or anomaly type. The techniques that are investigated in the book are perfectly legitimate scientifically tested methods, and not based on wishful thinking, self-deception and selective memory.

Here is a machine translation from the website ->
--------------------------------------------------
It is little known that some remarkably good tracking services provide settle with LF / low tracking devices. Even with a small level DCF77 receiver, metal pipes can be track, even when they are at a depth of several meters. Also foundations, in particular armoured, as well as cables and bunker can detect. Depending on conductivity of the surrounding soil, also more difficult objects can with the slightly more complex integrated devices determines how galleries and other spaces are.

Various inductive measurement allow to examine the ground surface metallic body. Special techniques and applications can be for efficient search of cables and pipes, resulting, for example, you can selectively pursuing only certain objects.
The book "Positioning technology in the LF / VLF range" provides an overview of the different detection methods in the specified frequency range and shows the possibilities and limits. While the above reports and findings relate to a large number of locations, which were carried out with self construction equipment in different performance classes from different people.
First of all, the reader is given an overview on the different detection methods. Then explains the corresponding equipment on the basis of block and function diagrams. Special attention finds thereby the sensor coil as main body in the signal.
The passive procedures are different elaborate reception beacon in the Center. Special Schaltungsapplikationen bring a considerable increase of the detection sensitivity to be pointed. These include systems with the ability to compensate for reading or different differential measuring systems with the aid of two or four sensor coils.
In the active process distinction is the aforementioned LF VLF location using own broadcasting of different inductive techniques of positioning. While for the first grouping during the detection process, the transmitter is firmly placed with its antenna and the receiver is led to the finding of objects over the area to be examined, the inductive detection equipment usually consist of a combined mobile arrangement.
Also come for the selective pipe and cable search, depending on local conditions, various active methods in question. Carefully run the theoretical previews to the cable finding include also facts and formulas that are relevant for the other thematic areas referred to in this book.
A not insignificant part of the book is devoted to the practical implementation of the location. It also limits the applicability and the advantages of different methods are pointed out. Some sketches show the signal behaviour of the sensor at various distances and angles to the object, as well as a sensor coil guided tour through the object.
A valuable aid for the subsequent signal evaluation in locating practice is also the knowledge of the interrelationships of certain errors and their impact on the detection sensitivity.
Described and shown on devices with the UAP system or in the compact and extended form with the new UO system can be built up. The latter provides the basis for the newly created modular LF / VLF positioning system of the author.
From a wealth of options of electrical connections, the author at the end of the book presents a small, but powerful tracking device with an operating frequency of 77.5 kHz. As more detailed construction description a device system shows consisting of receiver and generator specifically for sensitive selective cable search.
The book is intended as a theoretical basis for further planned circuit publications of LF / VLF tracking devices on the basis of the UO Board System. It provides the necessary background knowledge for efficient use of used locating equipment the homebrewers as well as the operator of a finished device.
--------------------------------------------------

Although this part: "From a wealth of options of electrical connections, the author at the end of the book presents a small, but powerful tracking device with an operating frequency of 77.5 kHz." does sound like it could be a PDK (anomaly detector), the author goes on to say: " As more detailed construction description a device system shows consisting of receiver and generator specifically for sensitive selective cable search.", which I think clarifies the statement.

Maybe bernte_one can confirm or deny this, as he has a copy of the book.

[Davor]

Seen from the principle this is like magnetometer because it doesn't matter if some longwave signal produces a magnetical field strengh or the earths magnetical poles.

This is a very good analogy, except that Earth static magnetic field is not affected by coloured metals, and LF is. The rest of reasoning is pretty much the same.
As for wave/field conundrum, to speak about wave phenomena like reflection you need object of a wavelength size, and by metal detecting in VLF/LF you apparently don't. There is only one phenomenon that deals with travelling waves and and sub-wavelength distractions on it's path: scattering. It happens even with minute change of phase due to sub-wavelength differences in medium. This analogy may help you understand ground wave as well. EM waves will travel through any medium that supports both E and H components in any ratio.

[Davor]

Although this part: "From a wealth of options of electrical connections, the author at the end of the book presents a small, but powerful tracking device with an operating frequency of 77.5 kHz." does sound like it could be a PDK (anomaly detector), the author goes on to say: " As more detailed construction description a device system shows consisting of receiver and generator specifically for sensitive selective cable search.", which I think clarifies the statement.

There is nothing LRL related in this book. Only hard facts, and working principles. If by any chance some device was condemned as LRL, but working on this principle, it was unjustly classified.

First and foremost, a wave consists of two components, E and H. They are mutually orthogonal. Separate wave components may be detected by short (<< lambda) electric or magnetic "dipoles". A short magnetic dipole is a ferrite rod, or a small loop. To make it completely separated from E field it must be well shielded, or working in a balanced mode. Friese chosen balanced mode (FKK approach ). Over an unobstructed homogeneous terrain, a ferrite antenna would have a minimum for detection of near surface (ground) wave when pointed vertically. Any conductive object, or void, shall act as a wave scattering point, and thus perform as a new field source of minute amplitude. Because it is close by, it will ruin the minimum reception as you approach to the buried object, yet right on top of it the minimum reception conditions will happen again, hence a sharp notch. That's the reason these detectors are designed as hanging contraptions to maintain vertical orientation, very similar to certain magnetometers.





The other option is a gradiometer configuration, where difference between two sensors indicate a buried object (or void). There is no notch on top of the object, but pairing two sensors, and observing their difference will create it.





I'm struggling with my German so I still have no idea what is meant by "sensitive selective cable search" other than "lost in translation". There is a method of actively exciting the cable at it's end, so perhaps it is the "selective" part. I'm not sure. Anyway, this is a very legitimate method, and if any device classified as LRL follows this path, it is classified wrong. Any abrupt change in soil permeability, permittivity, or conductivity can serve as a scattering point, so if someone calls it "anomaly" does not automatically mean the device sensing it is a LRL.

[Qiaozhi]

There is nothing LRL related in this book. Only hard facts, and working principles. If by any chance some device was condemned as LRL, but working on this principle, it was unjustly classified.

Thanks Davor.
Perhaps Funfinder will now understand that the book has nothing to do with swivel-handled devices or PDKs.

[ivconic]

Ah so welche art von scheiße ist dass!?


P.S.

[bernte_one]

ivconic thats great right humor at the right point

@funfinder dont take the things too serious its some science but mostly hobby
and hobby is for fun

@davor
if you have some problems with translation on the book i can help you i will translate it better than google translator

[Qiaozhi]

Ah so welche art von scheiße ist dass!?


P.S.

I'm going to try a second time to order the book. Then I can see for myself what kind of scheiße it is.

[Funfinder]

@ Qiaozhi
> Perhaps Funfinder will now understand that the book has nothing to do with swivel-handled devices or PDKs


Not the book and not the dowsing or pure fantasy locators, but the EM-field anomaly detection.
And of course those detectors or technique we are talking here is not long range but pretty short range.

Qiaozhi, you as the inventor of this "fake demonstration LRL" detector should know what it detects.

But if a person like Morgan tells that his PDK works if some TV radio stations are transmitting some EM-field-power and if we
hear that those Mineoro and PDK detectors lose completly the signal if the target is very close than the similarity is obvious.

And of course it's not completly like a magnetometer, its an EM-field distortion meter, tuned to some strong enough frequency source
likely in the longwave range so also noble metal will create inductivity-distortions.

A further difference is that those PDKs are used horizontally and register even very weak changes of the magnetical component of the
tuned longwave while those "real working" pipe locators are used vertically with the coil very close to the ground and they need a
much higher signal-change until they start with the signal-output.

With some skill it would be pretty simple to modify such a "real working long wave induction field pipe etc. locator" into one of those pseudoworking PDKs.
And if using the gradiometer design it even would work directional. The only difference is that those PDKs have both ferrite coils directly at one and the same ferrite core.


But why bother with this stuff?
First I wanna see useful test-results and which of those locators is the most sensitive and under what conditions and then I am interested,
because it doesn't bring any benefit if in theory everything looks very fascinating and shiny and in real its totally bullsh*t.

For deeper buried live wires or for wires where its possible to inject some signal into one end this technology of course will work much better as an usual metal detector,
like a electrostatic-detector works better to detect sparks or high-voltage, but this is not of interest for me:

the big question is: does it detect better cavity, ground differences like fundaments and deep buried metal objects as a detector with large coil?!

If you check out the attached pdf the software for the EMFAD looks pretty the same as for one of those computerized magnetometer scanners.
Cavity is blue, metal is red and the usual ground is green - this is the common setup.

So it is also the question, concerning cavity and deep metal: is one of those overpriced magnetometer-treasure-detectors more sensitive and reliable -
as example one of those expensive OKM magnetometer detectors, or is the long-wave better (because it also detects noble metal objects much better).

btw. also noble metal objects will distort the earth-magnetical field so they are detectable by sensitive magnetometers, but with very bad signals.


Well, perhaps the cable locator technology is the fantastic solution for large and very deep stuff, especially because it is much easier to handle than a 1m coil.

We will find it out here in this thread, hopefully...


And if somebody here has plans to built such a detector let me know how you wanna realize the signal output.
LCD display could be a little bit too complex. So perhaps by a sound signal that changes or by a row of bright LEDs near the handle.


Most of the time, same with magnetometers, such detectors only make sense if you collect and save the data from a large area
- per instance by walking 10m rows 10 times to get a signal-strenght-picture of a 10x10m square - that way the walls of bunkers can became visible.


Without such screen-output and data-processing-computer technology only huge differences of the signal on your way from A to B
will lead to "finds". Same with those vertical holdable "cheapo"-magnetometers who will tell you if you run over a large iron-object
but they will not show you the weak differences of the field below or cavity.

[Funfinder]

@ Davor

thx for the pix.
In what context was this "sensitive selective cable search" - perhaps I can help you to translate the meaning etc.



> EM waves will travel through any medium that supports both E and H components in any ratio.

Interesting stuff, just the "support" sometimes is highly complex. And it is not just a wave, this is a common misconception,
it is an oscillating electron-field-materie-wave-package, thats why light can be reflected by mirrors but also can go through glass.

A pure wave in the universe, which is vacuum empty, would have no medium to "ride" on it.
Same with acoustic vibrations, those are not transportable if there is no air or other "interacting-substance".


For our longwaves and the usual ground conditions we will find that those also will not penetrate everything.

Simple test:
Walk with your longwave radio into the cellar or drive with the car into some tunnel and check out the LW or AM reception-quality - if you have any at all.

by the way the ground is for longwaves also the electrical ground, thats why a good longwave to shortwave radio antenna should be grounded
to get the most highest selectivity and sensitivity.


Aus Wiki:
Mittelwelle oder Langwelle Die Bodenwelle ist bei Mittel- und Langwellensendern von großer Bedeutung. Langwellensender haben eine Bodenwellenreichweite bei durchschnittlicher Bodenleitfähigkeit von bis zu 1000 Kilometern, Mittelwellensender eine solche von 250 Kilometern, wobei der exakte Wert von der elektrischen Leitfähigkeit des Erdbodens (ein Boden mit hoher elektrischer Leitfähigkeit wie Meerwasser ergibt eine größere Bodenwellenreichweite als ein solcher mit schlechter elektrischer Leitfähigkeit wie Wüstensand), der Sendeleistung und der Art der Sendeantenne abhängt. Die Raumwelle wird in diesen Frequenzbereichen tagsüber von der Ionosphäre absorbiert. In den Nachtstunden findet eine Reflexion an der Ionosphäre statt. Hierdurch erhöht sich die Reichweite beachtlich. Aus diesem Grund kann man in den Abendstunden mehr Sender im Lang- und Mittelwellenbereich empfangen, als am Tage. Allerdings kann es auch zu Verzerrungen kommen, wenn Boden- und Raumwelle mit gleicher Intensität am Empfänger eintreffen. Man bezeichnet dies als Nahschwund.



The important stuff translated:
The groundwave for longwave spreads over 1000km and for AM (= called "middle wave" in german) 250km if the ground is good enough (the sand in desert or the rocks of mountains is not good, saltwater is pretty good). In daytime the "spacewave" of LW and AM gets absorbed by the ionosphere. If ground and spacewave don't match (by reflections, self deleting by phase-shifts etc.), distortions will occure.

50% of the transmitted energy from LW to SW spreads over ground-waves (but only if the ground is good enough for this task).

[Davor]

A pure wave in the universe, which is vacuum empty, would have no medium to "ride" on it.
Same with acoustic vibrations, those are not transportable if there is no air or other "interacting-substance".

Even the Universe is filled with ions, and they don't hinder the visibility of distant stars. The characteristic impedance of any medium, including free space is Zo = |E|/|H| and for free space it is somewhat below 400ohm. Soil has both some extra permeability and permittivity, hence a different Z, but also conductivity that causes losses. That's as simple as that. Reflections, diffraction etc. are not unlike for optics, only the wavelengths are much longer.
Unlike eddy current detection of common detectors, we have bulk object that causes local phase difference, or anomaly (if you insist).

As I said before, EM fields are for real, and instruments utilising them are also for real. It is only a perceptual problem that wrong people using terribly wrong instruments not related to physics are using the same terminology, and apparently some people instantly become jumpy whenever a term "anomaly" is utilised.

Thanks for offering assistance in interpreting the book, but I think the detail I didn't understand was not there to understand at all. It was a kind of summary that draws it's own conclusions that George quoted, yet neither it exists as such in a book, nor it can be traced by it's meaning in a book. It was just an odd interpretation.

[Funfinder]

thanx Davor for the info that this book issue is solved.


And pure scientifical seen this whole atomic energy particle stuff of course can be a very fascinating topic,
seems that you are also interested in such things.
Besides the ions the universe also is full with very thin gas-clouds (aka dark materie) and radiation of all kind incl.
this background noise where they say it is a remaining of the big bang.

Though for mankind always the practical aspect is more of interest - people are happy with their smart-phones
or when the sun is shining and don't care about the scientific or technical details.

Therefore we must confess that those "radio-receiver-detectors" are not really of high-interest in the
usual treasure-hunter scene, but perhaps this could be changed by improved technology and genious developments.

If such a detector would not just being fixed to one small and weak frequency-band but grabs the whole short-wave radio spectrums EM field
per instance, a much higher detection-contrast-factor could be realized. With such receivers even free energy is available, they simply soak
up a very large frequency-range from the EM fields energy (with large antennas) and convert them into voltage by diodes and capacitors.

Davor, so you have already this radio-detector-book - do you?
If so, are you planing to built such a circuit and experiment with it?

In your hands it could lead to some interesting results concerning the real useful working metal-detection possibilities.
Perhaps you may find out and document what is the minimum long wave EM-field-strenght etc. such a detector needs to find buried metal objects
on a real useful and practically seen acceptable level. Does it work with AM, too, or only with long-wave, and what is the difference? Such questions.

by the way the completly vertically coil position of such detectors may not lead to good detection results if the wave was diffracted as it happens
with FM (UKW) at regions with mountains - and this applies not just for ultra-short waves.

Some years ago I found a sketch with the best ferrite coil position for best AM radio reception gain - no idea where it is now.
here is some info: http://de.wikipedia.org/wiki/Ferritantenne

If the end shows to the transmitter (horizontal ferrite showing to the radio-transmitter antenna) the signal is minimal.
But if the ferrite-antennas position is 90° to the sender and 90° to the polarization, it is maximum.

This means that such a long-wave anomaly (distortion) detector with vertical hanging ferrite antenna only works correct
for long wave stations that uses a horizontal antenna (which is common because of the huge wavelenght).
AM-radio stations (MW) often use vertical antennas thats why the radio-receiver all have horizontal positioned ferrite antennas.

But if the longwaves have no problems with huge angle diffractions and the transmitting antenna is horizontal
and the land is flat without hills or mountains it should work with vertical ferrite-antenna.


So good luck and keep us informed about your radio-metal-detector experiments!
It's really interesting!

PS - for technical inspiration - below one of my BNC-jack-moded world-receivers so its usable with RG-58 or thicker coax cables
which are attached to roof- and other large or amp'd antennas incl. grounded shielding.