directional detection

[Funfinder]

To find an object from a distance different detection-methods are possible:

- focusing or amplifying a radiating power source
- measurement of different field strenghts
- calculation of reliable data

And in our LRL case:
- analyzing the field around the object


The most important question is:
what kind of directional antenna works the best and
what kind signal does it detect, electric or magnetic.

electric: natural or/and artifical
(static energy, ion-storms, lightning / EM waves of all kind)

magnetic: natural or/and artifical
(earth magnetic field, magnetite / the magnetic of EM waves)


An AM-ferrite-coil works the best if it is horizontally positioned
and at a 90° angle to the vertically transmitting AM-antenna.

An FM-antenna (the same with satellite signals) must have the
same polarisation.

The usual metal detectors coils works like an electromagnet-wire
concerning the concentrated magnetical strengh in the middle
which then radiates up and below. This is also directional -
directly in front of the coils center (or in the middle) the best detection is possible.



Now lets see what scientifcially knowledge you can contribute.


This is another try to get here in this forum some real advance
concerning "how LRL work".

But it needs scientifical thinking methods and not "dreaming"!



Logically seen a certain antenna-design also leads to the
received kind of signal. Per instance with a telescopic-antenna
AM reception will be difficult.

If you see at the drawing there are squares with A-E and 1-9.

Each of this areas must have a different field-strengh if LRL detection
works! Because the buried metal doesn't radiate by it self, as long as
it is not radio-active and even then the x-rays could get stopped by the ground.

btw. another directional detection method is with reflecting shields like
satellite-dishes or metal pipes. As example you can built directional
WiFi antennas with peanut-cans. But such antennas only work for
very small wave-lenghts, UHF and upwards.



Standing at one of such squares with the pistol-detector represents
a special "field-situation" but starting at each of these points
the detector needs to have the possibility to locate the next
square with the higher energy-level.
Therefore the directional antenna design is crucial important.

A pure static-energy-or EM-field-strenght meter without
a correct directional antenna design always can only detect
or measure the actual situation but without further coordinates.
Of course such a device would be completly useless for long range,
cause any direction could be the right one.


So at least two different coils are needed where the received
energy level between both of them gets compared. Comprende?


So now please take a look at the different antenna-designs and tell me
what kind of signals will be detected!

[WM6]

Good Funfinder, Thanks.

If we go further in those "detecting transmitted signal" theory, there are 3 way of such detecting:

1.) detecting from target reflected signal,

2.) detecting target shadow of signal

3.) triggering target to resonance by TX signal and detecting resonating target

No one of mentioned method are capable to detect small metallic target as coins. First two only for bigger ore deposit in theory. Only a third method has been used in practice and applied in devices for detecting resonating things as underground cables and pipes.

[FrancoItaly]

Hi All

Any explanation must take into account the features of the phenomenon, i.e.the relationship with north/south direction and the fact that a single meter of B-field, E-field, infrared, EM in the full range of frequency, they cannot sense the phenomenon. A non shielded trasmitting coil (with RX coil or not) followed by a high gain stage it's very sensible to "sky/compass" effect. This effect is present in all locations regardless of the configuration of the territory. Not shielded coil means that it's sensible to E static fields and north/south direction makes us think of the Earth's magnetic field in some manner it influences the phenomenon.
I favour the atmospheric electric field with solar wind and/or cosmic rays. The very important thing is that the buried target doesn't emit anything but only it disturbs the surrounding environment and this disturb is directional that is for example a signal east-west direction 1 meter along and nothing for other directions. This is a true case of a brass bullet detected by a lrl and a MD. To understand the inner cause of the phenomenon is not so important, I think it would take very sophisticated instrumentation but it is important the way to detect it. The direction of max sensitivity not always it is east-west or north/south and the north/south direction is not equal to south/north direction. I think to a ground battery combined with south/north ionic channel or maybe the lines of force of the atmospheric electric field are curved towards the North.


Best Regards

[humhum]

Originally Posted by FrancoItaly

Hi All

Any explanation must take into account the features of the phenomenon, i.e.the relationship with north/south direction and the fact that a single meter of B-field, E-field, infrared, EM in the full range of frequency, they cannot sense the phenomenon. A non shielded trasmitting coil (with RX coil or not) followed by a high gain stage it's very sensible to "sky/compass" effect. This effect is present in all locations regardless of the configuration of the territory. Not shielded coil means that it's sensible to E static fields and north/south direction makes us think of the Earth's magnetic field in some manner it influences the phenomenon.
I favour the atmospheric electric field with solar wind and/or cosmic rays. The very important thing is that the buried target doesn't emit anything but only it disturbs the surrounding environment and this disturb is directional that is for example a signal east-west direction 1 meter along and nothing for other directions. This is a true case of a brass bullet detected by a lrl and a MD. To understand the inner cause of the phenomenon is not so important, I think it would take very sophisticated instrumentation but it is important the way to detect it. The direction of max sensitivity not always it is east-west or north/south and the north/south direction is not equal to south/north direction. I think to a ground battery combined with south/north ionic channel or maybe the lines of force of the atmospheric electric field are curved towards the North.


Best Regards

Very correct info and I agree with you Franco , plus I think that when Earth's magnetic field dissolution or impaired from buried metal, around this metal consists generation from all Transmitters frequency. Now this buried Metals is so like Magnet and Receive all freq. , because Earth's have very strong magnetic field .

[Funfinder]

Thanx everyone for your "realistic" interest.


Now I have created a second drawing for better illustrating the
following conclusions:


The starting point is the electronic circuit itself.

I'm shure we have already enough info that it is either based on electrostatic or on long wave reception in combination with at least "power-level" comparing circuits.

The solution ist very simple:

Instead of using a selective long-wave radio-receiver circuit that
concentrates on just one frequency it observers the magnetical
part of that waves over a large range which will give a 1000x times
higher sensitivity.

It's shure that the magnetical part of those VLF waves get detected!

1. because of the coil-antennas
2. because only the magnetical part interacts on a useful level
with the buried objects and penetrates the ground


Now let's compare it with the Two-Box detector:


Both coils are balanced and if the metal box gets enough
distance to one of the coils the induction starts, reduces the
orginal fields and creates imbalance.


Under "natural conditions" it will be the same.

The LRL passive receiver is balanced to the field-condition.
It doesn't need a transmitter because there are enough
long-wave-transmitting sources available "for free".

If those waves come across a location with buried metal object
they have to interact with it - this is a physical law.
The induction-process works on a steady and longtime basis.


The finetuned passive receiver will detect the same way as the receiver coil
of the two box if the "inductivity situation" of the ground changes -
no matter if it gets stronger or weaker.
And the directional antenna leads there, because if the left coil
starts to get more or less energy it is clear that the changing
field situation must be near the left side!





The metal object works like an antenna with shortcut,
it converts the power of a huge electromagentical spectrum
into it's own energy, it sucks away this free energy and
leaves the surrounded region with a slightly changed
field-condition.


The reason why some of those detectors are sensitive to
north south direction has to do with the magnetical receiver
circuits and the extreme sensitivity that is needed to
detect those very weak field-differences.


The picture below shows the real situation very well:

There are many different EM-fields interacting which makes
the whole thing very complicated.

Perhaps if buried metal object interacts with the electrostatic
force-field this field also disturbs the field lines of the
earth-magnetical field and of the magnetical pulses of all
kind of long-waves.


The crucial point is the receiver circuit itself!

As described already, it has to work on a huge frequency range.

From 5kHz to 100kHz it has to measure the magnetical power
level of this range like a voltmeter.

If such a receiver would be finetuned to 50,972 kHz and observers
only a spectrum of plus minus 5 Hertz the "magnetical induction difference" near a
buried metal object would be almost nothing - no way to detect it.



btw. it's a mistake to think that a buried metal object would
leave the surrounding EM-Fields untouched. It will change it like
a find close to a metal-detectors-coil, just on a much weaker level.

And the EM-fields are not just available above the ground!

Depending on the mineralization, moisture and consistence
ground can transmit EM-waves even better than air - we see this with seismic waves (an earthquake in the air would be harmless).

And ground is not always the huge minus-pole that swallows all electricity or EM-fields. If this would be the case no metal detector could work, because all radiation would be "shortcuted".


Now a good question:
Why such a magnetical long wave LRL-locator won't get confused
by different radio stations (see picture) or only is useful to find
the direction where the radio-station is located?

Answer:
Because it is not finetuned to one single radio-station,
but to a huge long-wave spectrum.

It is almost comparable with a little AM-Radio and the
white-noise level it has, depending if it is used inside
of cave, tunnel, cellar compared with a tower, rooftop or hill.
Or compared with antenna attached or not.

Such a radio will detect the location because it has a
different field-strengh level.




So what is really needed for such a detector?


- high inductive coil antennas, each at least 100 windings, the more the better and also the diameter must be not too small.
Those coils must be really fixed tight and strong.

- a nonselective but wideband long-wave passive receiver stage

- electronically very stable and high sensitive circuits for reliable
signal level comparation-tasks

- adjustable sensitivity for wide varying country, weather, ground and other EM-field strengts

- the possibility for fine-adjustment close to real outdoor conditons
(trimpots easy adjustable directly while already in nature)



Any questions?

Shure, there always will be more to discover, but personally I'm convinced
that if LRL works, it will only work reliable this way!

And it's pure logical, its like a gigantic high sensitive 2box-detector with moving receiver while the radiation comes from all sides naturally.

And I'm shure if we isolate the "passive receiver" circuits from many
of those homebrew LRLs we have the proof that they are using
a simple long-wave receiver with magnetical-antennas!
Even the ferrite coil antenna works on the same principle.


What really count's is to understand that this "phenomenon"
is not based on one tiny and weak frequency, but on the sum
of a huge range of a large long-wave EM-field-area.

For an usual metal-detector it would costs an unbelievable
huge amount of battery-power if it would receive and transmit
on 100 or more frequencies at the same time!

In nature this is different - the most of the usual long wave radiation
is pretty weak and the source very distant, but it multiplys extremly
if "melted together".

We see similar effects at the aurora borealis (the northern light) and its proven that sunstorms even can interupt completly powerful radio-communication. If those energy-fields are summing up they are really powerful and of course easy detectable, too.




A final word about how good will it work in practise:


2 factors are important:

- enough powerful free available long-wave radiation
- stable and sensitive enough receiver


Most of the time the second point will be the problem!
Some long waves are available everywhere, but will they
give enough detection contrast???

A very sensitive and stable receiver will have no problem,
but a homebrew DIY box will need a certain amount or power
of given LW-radiation or it will detect no difference or nothing at all.

And if there is snow or rain the EM-field gets weakend even more.

But such detectors may function good enough in the evening time
and if weather is good.



How to built it?

The easiest way would be modifying a high sensitive LW-radio.
It needs 2 high inductive magnetical-coil antennas and a little circuit
to see at what antenna is more or less energy at the moment
and while pointing the detector into different directions.

How to make such a receiver "unselective"?
Simple remove any "resonant circle" (coils, capacitors) that tunes the receiver to
a certain frequency. But I hope we can get more precise info
about this topic. The receiver also should stop somewhere at max.
200kHz because the magnetical energy of higher frequencies
has much more trouble to penetrate the ground.

And finally it is important to go outside to calibrate this receiver
because calibrated at home it will not work outside and vice versa.


Good luck!

[FrancoItaly]

Hi Funfinder
I don't agree with you, my lrl has no magnetic parts, only a small inductor (3 turns, diameter of 1 cm) and mainly a stylus antenna, only 20 cm works fine. A not shielded coil (PD pistol) means sensitivity to static charge and the working frequency seems to be unimportant and this seems to exclude RF emission. It's true that RF waves have B-component and E-component but I experienced the same behavior in many different places between them, close to the sea and in the mountains and it is unlikely that radio emissions cover evenly the territory. I think that the penomenon it's simply this: we move the lrl from from left to right and vice versa, the lrl sense a change of the E-field and this changes the amplitude of an oscillator or better a high gain amplifier in oscillating mode. If this oscillator is "hard" to "modulate" we sense only the sky/compass effect.

Best Regards