New detecting method?

[g-sani]

http://iospress.metapress.com/content/q767074h6n070577/

I found this page accidently and I thought lets have a look because it is something coming from a University and I tried to read the concept but I couldn't.
Do you have to pay for it? This is what I understood.
May be I am wrong.

[Seden]

By typing in the title on Google, I found enough of the article here via Google Books that explains the tests with a schematic and graphs of the results. Wow, very interesting and nice to have a new idea for our hobby.

SWR take this very seriously.

Randy

[epitopios]

to g-sani
the article says:
A new type of magnetic field detection system, which can operate at a frequency below 1 kHz, is proposed and developed. The system consists of a 40-turn-coil to generate the magnetic field and a magneto resistive sensor to detect both the amplitude and the phase signal of the magnetic field induced by eddy-current and magnetization of the samples. The magnetic field detection of ferro- and non-magnetic samples using the system is demonstrated and discussed.

accidentaly , last days I made a receiver 100Hz-11Khz
if you find a operator uder 1Khz , maybe I say maybe ....or if someone can give us a design????
να τα παντρέψουμε , τι λές Γιώργο ?
friendly , epitopios
σε Π.Μ.

[J_Player]

to g-sani
the article says:
A new type of magnetic field detection system, which can operate at a frequency below 1 kHz, is proposed and developed. The system consists of a 40-turn-coil to generate the magnetic field and a magneto resistive sensor to detect both the amplitude and the phase signal of the magnetic field induced by eddy-current and magnetization of the samples. The magnetic field detection of ferro- and non-magnetic samples using the system is demonstrated and discussed.

accidentaly , last days I made a receiver 100Hz-11Khz
if you find a operator uder 1Khz , maybe I say maybe ....or if someone can give us a design????
να τα παντρέψουμε , τι λές Γιώργο ?
friendly , epitopios
σε Π.Μ.Hi epitopios.

There is no circuit shematic showing components or values.
The designers from the Okayama University gave this vital information that explains the technique to discriminate metals:

[g-sani]

to g-sani
the article says:
A new type of magnetic field detection system, which can operate at a frequency below 1 kHz, is proposed and developed. The system consists of a 40-turn-coil to generate the magnetic field and a magneto resistive sensor to detect both the amplitude and the phase signal of the magnetic field induced by eddy-current and magnetization of the samples. The magnetic field detection of ferro- and non-magnetic samples using the system is demonstrated and discussed.

accidentaly , last days I made a receiver 100Hz-11Khz
if you find a operator uder 1Khz , maybe I say maybe ....or if someone can give us a design????
να τα παντρέψουμε , τι λές Γιώργο ?
friendly , epitopios
σε Π.Μ.

Well epitopios something like gold gun comes up to my mind.
I don't know, people involved in electronics can tell us more.
In Greece they say that 20Khz is allright for a receiver to be used for treasure hunting since there is transmition over here in this frequency.
The thing is you have to know what the meter is reading plus learning to read the audio signal is important as well.
VLF transmitters are not an easy subject when to be used for treasure hunting.
Many years back I used a AL718 and I was suprised to see that it was
responding in a known target(50kilos) of copper wire from 50mts away.
Then it was many VLF stations in use for Navy but now there are not.
I have it always in my mind as a problem to be solved in order to use my AL707 properly but I always hold back until I can see something serious as a solution.Okm sells 10Watts VLF Txs for big money.
I believe that 50W is a must for long range detection when using a receiver.
Any possible help in that is welcome.

[WM6]

I believe that 50W is a must for long range detection when using a receiver.


.

50W? Do you intend to sense gold from home on other hemisphere?

0.3W can be here far enough to reach way deeper than signals from former navy stations.

Secret is not in Tx electronic and its Watts but in proper build Tx antenna for ULF/VLF band.

[Fred]

Secret is not in Tx electronic and its Watts but in proper build Tx antenna for ULF/VLF band.
Maybe this is why you need more power with inefficient antennas (ferrite), or gigantic military stations far away :D

[Seden]

WM6 is right. If you used a large ferrtie bar antenna and mounted it on a tripod with a 1 watt transmitter you would have all you need to use your AL707. So easy at 20 khz to make a simple OP-AMP signal generator and feed it into a audio power amp IC. Couldn't cost more than $25USD.

Randy

[J_Player]

WM6 is right. If you used a large ferrtie bar antenna and mounted it on a tripod with a 1 watt transmitter you would have all you need to use your AL707. So easy at 20 khz to make a simple OP-AMP signal generator and feed it into a audio power amp IC. Couldn't cost more than $25USD.

Randy
Hi Randy,
What kind of ferrite, and what size do you recommend?
what size wire, and how many turns?

I am sure the oscillator can be adjusted to whatever inductance and response the coil assembly would produce.

Best wishes,
J_P

[mikebg]

Low power transmitter in catalog of Geonics Ltd.
The TX27 is a portable VLF transmitter supplying a VLF field for surveying with either the EM16
or the EM16/16R if remote broadcasts are weak, intermittent or poorly coupled with the target.
For EM16 surveys, the TX27 antenna consists of a long (typically 1 km) grounded wire.
PRIMARY FIELD SOURCE: Grounded wire or 500 x 500 m loop, current adjustable, 0 to 2 A
OPERATING FREQUENCY: 18.6 kHz
POWER SUPPLY: 120/220 V, 350 W motor generator
DIMENSIONS: Transmitter and loop; Shipping: 89 x 29 x 39 cm
Generator; Shipping: 50 x 27 x 36 cm
WEIGHTS: Transmitter and loop; Shipping: 32.5 kg
Generator; Shipping: 17 kg

[epitopios]

WM6 is right. If you used a large ferrtie bar antenna and mounted it on a tripod with a 1 watt transmitter you would have all you need to use your AL707. So easy at 20 khz to make a simple OP-AMP signal generator and feed it into a audio power amp IC. Couldn't cost more than $25USD.

Randy

οκ , but we will have a signal distortion or not ??

[J_Player]

Low power transmitter in catalog of Geonics Ltd.
The TX27 is a portable VLF transmitter supplying a VLF field for surveying with either the EM16
or the EM16/16R if remote broadcasts are weak, intermittent or poorly coupled with the target.
For EM16 surveys, the TX27 antenna consists of a long (typically 1 km) grounded wire.
PRIMARY FIELD SOURCE: Grounded wire or 500 x 500 m loop, current adjustable, 0 to 2 A
OPERATING FREQUENCY: 18.6 kHz
POWER SUPPLY: 120/220 V, 350 W motor generator
DIMENSIONS: Transmitter and loop; Shipping: 89 x 29 x 39 cm
Generator; Shipping: 50 x 27 x 36 cm
WEIGHTS: Transmitter and loop; Shipping: 32.5 kg
Generator; Shipping: 17 kgHi mikebg,
Geonics Ltd. has some very nice geophysical testing instruments in their catalog along with their logging systems. These could be very useful for mapping both shallow data and data from much deeper in the ground. I like the products they show. They have a particularly interesting arrangement of their PI metal detectors that use a focusing coil and digital data loggers that log multiple sample readings taken at various delays along the decay curve. These look like good tools to use for geological surveys.

I think epitopios is looking for a hand-held transmitter that tells him the direction where a metal object is buried at some distance, rather than a large loop placed on the ground. He is probably interested only in locating shallow metallic items (less than 5 m deep) without performing a survey, by simply holding a detector that will indicate which direction the metal is located.

Best wishes,
J_P

[g-sani]

50W? Do you intend to sense gold from home on other hemisphere?

0.3W can be here far enough to reach way deeper than signals from former navy stations.

Secret is not in Tx electronic and its Watts but in proper build Tx antenna for ULF/VLF band.

0.3W?
Why nobody did it then?
What I know is high power and very long aerials because of the longer wavelength.
If low power could be used then they would do it.Well as far as I know.
The thing is which one would be best for treasure hunting whith a receiver to go on target?
1. Sending the frequency into the ground using a probe?
2. Air transmision using a special aerial? What type of?

[g-sani]

Hi J_P
Don't you think that 5m depth is enough?
I think it is.
The best for me is a handheld device for a radius of 200 meters.
I know I am asking too much.:D

[WM6]

οκ , but we will have a signal distortion or not ??



Probably yes, but nothing bad if you use as TX very simple and cheap so called self-modulated transmitter. Find one schematic on web and as previous say you do not need more than 0.3W of power output signal to cover your actually search field and much much more. Simple try and you will see.

Antenna have to be resonate on selected VLF/ULF frequency and adjusted by impedance to transmitter output or on feeding cable (if you use cable to feed antenna it have to be adjusted by impedance on both side - at minimum reflected standing wave).

g-sani mentioned here good enough schematic for receiver, so called "gold gun" and Qiaozhi posted somewhere on forum. Basically it only have to be adapted to our TX frequency or vice versa and maybe need some mods. And again antenna is crucial part here too.

Main thing here, if electronic Tx and Rx stages was correctly build, come antenna. Antenna implementation can be different, regarding one needs and tendency, wound on ferrite rod too - even not so effective. Best solution for sure are wire antenna as pointed mikebg, but we need such gigantic antenna only for communication with other earth hemisphere and not for our limited search field. To cover our limited search field even ferrite antenna can be fully sufficient.

Practically two main type of antennas are applicable. Vertical stacked and circular radiated 1/4 wavelength antenna and directed frame (quad, triangle or circular) antenna. Vertical antenna can be put in the middle of our search field while directive antenna is usually placed on the edge of search field (higher-better, but especially vertical antenna have to be grounded).

Building of directive antenna on quad (circle or triangle) shape (1.5x1.5m) is well known from coil winding. We use coil calculator to determine Nr. of turns and inductance for given frequency and wire diameter. After about 100 windings we tighten coil, remove a bit of isolation from wire, measure inductance and recalculate coil data again. At the end antenna must resonate at Tx frequency. Then we need only to adjust antenna input to Tx output. Check this by put antenna at the virtually same position (nonmetallic carrier, radiating orientation and height) as it will be placed latter in search field.

Vertical stacked antenna can be build in such way: We use about 1.5m length rigid plastic tube with outer diameter of about 10cm and about 1.5m Alu tube OD 1cm. Then we use coil calculator and calculate coil for 4th upper harmonic of our Tx frequency (with coil inner diameter of 10 cm an length of 15cm). Mean if our Tx is working on 10kHz we calculate coil for 40kHz. Calculated Nr. of turns we divide per 15 which give our data of turns for each of 15 section windings. Then we wind 15 section of turns on plastic tube of about 9cm apart each other. One end of windings we connect to Alu tube which is stacked as extension of plastic tube other end to hot wire of Tx output. First (mean lower) of 15 winding sections have to be wounded with about 15 inter-windings connections for latter antenna tuning. This antenna is needed to be re-tuned on every search field cause of different grounding soil characteristic. Although once fitted on location comfortable for hunting, this antenna not suit best for less experienced.

[WM6]

0.3W?
Why nobody did it then?



Who is nobody, OKM?
Yes 0.3W is far enough.

Why OKM sell more Watts? Maybe for human vanity, you know, - "more power - more money" for OKM. And here ineffective "more power" is cheap for producer. But at the same time more power not mean more findings. Not at least by excessive power you can be quickly not only out of target but out of law too by strong widely disturbing interference. Not negligible too: by 50W of transmit power you need to bring with heavy bus accumulator to assure one day search.

This field is dedicated to art of sensitivity and harmony (resonance) not to question of power.

And probably they build antennas of very low quality - which are easy to produce but low effective antennas and try by excessive power to substitute this drawback, which is wrong approach but very profitable for producer of such things.

[g-sani]

Who is nobody, OKM?
Yes 0.3W is far enough.

Why OKM sell more Watts? Maybe for human vanity, you know, - "more power more money" for OKM. And here ineffective "more power" is cheap for producer. But at the same time more power not mean more findings.

And probably they build antenna of very low quality - low effective antenna.

No I am not talking only about OKM WM6.
First I thought the ones they make feed the signal straight into the ground.Somebody else told me that you just put the aerial on the ground.This is how it looks in the photo anyway.Check the last line of the characteristics.Only 10 meters? Is it "maximal sphere of action" the effective range or something else?

Features of the Control Unit

Operating Temperature: 0 °C – 50 °C
Storage Temperature -20 °C – 60 °C
Air Humidity: 5 % – 75 %
Waterproof: No
Dimensions: 25H x 22W x 17D cm
Weight: about 7.4 kg
Frequency Range: 7 kHz - 60 kHz
Amplified Output Power: 10 W
Internal Battery: 24 V
Operating Time: (full charged battery) about 3 h
Charging Time: about 10 h
Maximal Sphere of Action: about 10 m

[WM6]

Check the last line of the characteristics.Only 10 meters? Is it "maximal sphere of action" the effective range or something else?

Frequency Range: 7 kHz - 60 kHz

Maximal Sphere of Action: about 10 m



Yes, low effective antenna, nothing else. Maybe without such antenna only by resistive end you can reach the same "Sphere of action". Those antenna act only as TX output load to prevent Tx damage not as real and effective VLF/ULF antenna..

It is understandable that no one can build effective resonate antenna for wide Tx range of 7Khz to 60kHz. Practically impossible.

And why one need such wide frequency range? This is not working on VLF/IB or BFO principle where are some differences in detecting between frequencies. Here not, except partially in the immediate vicinity of target, but we are asking for some remote detecting. Here you need only one frequency say between 10-30kHz and resonate Tx and Rx antennas to selected frequency and as good as possible directivity of Rx antenna.

[J_Player]

Hi J_P
Don't you think that 5m depth is enough?
I think it is.
The best for me is a handheld device for a radius of 200 meters.
I know I am asking too much.Yes,
I think less than 5 m deep is what most treasure hunters are usually looking for unless they suspect there is a worthwhile treasure deeper. Many treasure hunters would be happy to have a detector that can locate a buried treasure 2 m deep from a radius of 200m.

There are geophysical instruments that can locate metal things at this depth and also over 5 m. But these are not hand-held locators that you can put in your backpack and expect them to point the direction of a buried treasure. They are used to perform surveys of an area that is plotted so the data shown on maps can be analyzed by a geologist to determine what is under the ground. VLF signals that geologists use are transmitted from large VLF beacons all over the world. They receive these beacon signals between 1-30 KHz, and can collect data up to 25 m deep in the ground, and sometimes deeper when holding a loop receiver antenna in their hand to pick up the distant transmitter signal.

But if you are looking for shallow anomalies at less than 5 meters, then you can raise the frequency up to 150KHz for better resolution in your survey. The large military VLF transmitters do not use ground probes for a transmitter antenna. They have a large arrays of antennas in the air. Geologists use ground probes to measure the ground resistivity and induced polarization, which are electrical measurements, not RF. The idea that you can get efficient wave propagation in the ground by using ground probes does not sound correct to me.

In order to use a small portable transmitter, I agree with WM6, that a small air core loop will probably work the best. From what I can see WM6 is very knowledgeable in how to make an efficient VLF transmitter, and probably understands the near field propagation and ground absorption better than someone who tells you it can be done best with putting probes in the ground.

Best wishes,
J_P

[J_Player]

Hi J_P
Don't you think that 5m depth is enough?
I think it is.
The best for me is a handheld device for a radius of 200 meters.
I know I am asking too much.Yes,
I think less than 5 m deep is what most treasure hunters are usually looking for unless they suspect there is a worthwhile treasure deeper. Many treasure hunters would be happy to have a detector that can locate a buried treasure 2 m deep from a radius of 200m.

There are geophysical instruments that can locate metal things at this depth and also over 5 m. But these are not hand-held locators that you can put in your backpack and expect them to point the direction of a buried treasure. They are used to perform surveys of an area that is plotted so the data shown on maps can be analyzed by a geologist to determine what is under the ground. VLF signals that geologists use are transmitted from large VLF beacons all over the world. They receive these beacon signals between 1-30 KHz, and can collect data up to 25 m deep in the ground, and sometimes deeper.

But if you are looking for shallow anomalies at less than 5 meters, then you can raise the frequency up to 150KHz for better resolution in your survey.
The large VLF transmitters do not use ground probes for a transmitter antenna. They have a large arrays of antennas in the air. Geologists use ground probes to measure the ground resistivity and induced polarization, which are electrical measurements, not RF. The idea that you can get efficient wave propagation in the ground by using ground probes does not sound correct to me. When geologists do want to transmit their own VLF signal, they lay a cable down on the ground in the form of a large loop maybe 1km diameter, then use their hand-held receivers to survey the area around the loop.

In order to use a small portable transmitter, I agree with WM6, that a small air core loop will probably work the best. From what I can see WM6 is very knowledgeable in how to make an efficient VLF transmitter, and probably understands the near field propagation and ground absorption better than someone who tells you it can be done best with putting probes in the ground.

Best wishes,
J_P

[g-sani]

Thank you J_P, I can undrestand that WM6 knows better the subject.
So what do you think it is best to use whith my gold gun?
Is it a necessity to transmit in exactly the same frequency as we receive?
Do you know if there is anything ready to be used in the market?

[g-sani]

Yes, low effective antenna, nothing else. Maybe without such antenna only by resistive end you can reach the same "Sphere of action". Those antenna act only as TX output load to prevent Tx damage not as real and effective VLF/ULF antenna..

It is understandable that no one can build effective resonate antenna for wide Tx range of 7Khz to 60kHz. Practically impossible.

And why one need such wide frequency range? This is not working on VLF/IB or BFO principle where are some differences in detecting between frequencies. Here not, except partially in the immediate vicinity of target, but we are asking for some remote detecting. Here you need only one frequency say between 10-30kHz and resonate Tx and Rx antennas to selected frequency and as good as possible directivity of Rx antenna.

I know that my gold gun AL707 receives in 19.6khz and also in another two lower freqs but how can I accurately measure the frequency myself WM6?
I think I have to verify the receiving frequencies myself first before I will see about the transmiter.
Thanks for helping.

[J_Player]

Thank you J_P, I can undrestand that WM6 knows better the subject.
So what do you think it is best to use whith my gold gun?
Is it a necessity to transmit in exactly the same frequency as we receive?
Do you know if there is anything ready to be used in the market?Hi g-sani,
I have never used any hand-held detector on the market that was able to locate buried metals for me at a long range more than about 1/2 meter, or maybe up to 2 meters for very large metal things when using a VLF loop. I only hear stories that other people say there are locators that can find buried metals at long range.

I have no way to know if a Gold Gun is best for you to use. If you can find a gold gun, then you could check to see if it is locating buried metals for you. If you find it helps you to find buried treasure, then you will know whether you should use it or not.

From what I understand, the gold gun is a receiver without a transmitter. I have no idea of what RF or electronic principle it uses to locate buried metal. But if it is only receiving RF, then it could be looking for the strongest signal strength, or it could be looking for some specific kind of modulation or interference at the frequency it is tuned to. I have no way of knowing because I don't know what the circuit electronics are designed to detect.

One thing I can tell you that if it is an RF receiver with added signal processing circuitry and no transmitter, then it is designed to receive RF signals from a distance, not from a transmitter at close distance from the receiver. If you were use a small transmitter at your hunting site, then the signal coming from this transmitter will be broadcasting RF in the near field, whose propagation properties are not the same as transmitters far in the distance. You will find that the field strength and radiated power pattern does not follow the math formulas that are used to determine what that signal will be if it came from a distant transmitter. But at least any modulation you send from a nearby transmitter will be preserved in the near field area.

If you want to know more about how to actually build a transmitter and receiver, I would recommend that WM6 is very knowledgeable about this, and probably has more experience and knowledge than most people in this forum.

Best wishes,
J_P

[g-sani]

Hi J_P
Once many years back a friend of mine gave me a gold gun al718 for a month to see if it can detect anything or not.
There was a single page inside its box roughly explaining its operation.
All I paid attention then it was a part saying that if the pistol like detector was pointed to a precious burried target goes silent.
I discovered some guns from the 2nd world war once from about 50 meters and some other time it was 5 or 6 bullets spread close to each other but only 15cm deep.I was surprised to see that it was easy to go on target.
The gold gun has a digital voltmeter giving different readings as you sweep it from side to side apart from the amplified audio signal in the speaker.
I didn't use it many times to say the truth but I could tell whith the experience I had those days that this pistol could detect something.
This is how and why I got my goldgun later on from a shop that was closing down in States.I bought it for much less money than what Accurate Locators used to sell it.
I discovered later on that probably this type of lrl doesn't work any more since most of the VLF stations arround Greece closed down.
Some other users here in Greece say that there are some emmisions in certain days but thats not a solution for me.
Even accurate locators made a Tx later and started selling it again until it was for some reason discontinued.
So I am in position now looking for a Tx to duplicate the emf fields of the old days that don't exist now.
But the truth is I always leave it behind J_P because I can not reach to a right conclusion of what is best to do.

I can put photos down of the cct or the pistol itself but I think somebody put some already in the forum under some other thread.

[WM6]

I know that my gold gun AL707 receives in 19.6khz and also in another two lower freqs but how can I accurately measure the frequency myself WM6?
I think I have to verify the receiving frequencies myself first before I will see about the transmiter.



I don't know what of instruments do you have in your lab.

If you start from "Gold gun" which is real for you, you need first to measure all of (as you say) three frequencies of your AL707. Do not believe to producers data it may vary, but because of ferrite antenna ("widest" Q) real data can be inside of acceptable tolerances.

There are some way to measure antenna resonance but first rule have to be that we may not to over-burden input LC circuit by direct measure instrument connection in a way to change his resonate frequency.

So we will try to measure without to over-lasting antenna circuit. Maybe you have or can lent some sort of reliable audio signal generator or signal generator for general use. If so, you first wind your testing transmit antenna from about 10 turns (1mm Cul) 10cm in diameter (or 10 turns on ferrite rods) and connect such testing antenna together with serial connected 1k pot (trim to middle position) to generator output. Put generator output on unloaded (max peak to peak output) square signal (typically 15vpp). Now you have your testing measurement transmitter ready.

Put your AL707 "ON" and approximate it to test antenna at about 20cm. Now you start to gradually change generator frequency from 0Hz to about 35kHz and watch for react from AL707 speaker or led. If you catch signal, try to establish his maximum. Frequency at which signal reach his peak is resonate frequency of selected frequency position of your AL707. Try the same way to establish other two frequency. In case of strongest signal from receivers speaker you can use attenuator on signal generator to get weak signal or put AL707 so apart from TX antenna to get weak signal from speaker. By weak signal we can more accurate establish peak and by this more accurate resonate frequency too.

In case of no signal from AL707 you can first regulate serial pot to lower resistivity of about 100E, more approximate test antenna to AL707 and at the end try to open it and measure signal at amplification stage by mV-meter or scope. To prevent possible damage hope that this would not be needed.

After you establish all three of antenna circuit resonate frequencies your next step is transmitter adopted to middle of three frequencies (or on one of his lower harmonics).

Here may you suggest to buy very usable testing instrument Portable frequency counter with possible use as field strength meter. You can search for it on eBay under name "GE FC-1 Portable Frequency Counter 10Hz - 2.6GHz". Usable to detect in-depended of transmitter and receiver resonate frequency of TX antenna and cheap.

[J_Player]

Hi J_P
Once many years back a friend of mine gave me a gold gun al718 for a month to see if it can detect anything or not.
There was a single page inside its box roughly explaining its operation.
All I paid attention then it was a part saying that if the pistol like detector was pointed to a precious burried target goes silent.
I discovered some guns from the 2nd world war once from about 50 meters and some other time it was 5 or 6 bullets spread close to each other but only 15cm deep.I was surprised to see that it was easy to go on target.
The gold gun has a digital voltmeter giving different readings as you sweep it from side to side apart from the amplified audio signal in the speaker.
I didn't use it many times to say the truth but I could tell whith the experience I had those days that this pistol could detect something.
This is how and why I got my goldgun later on from a shop that was closing down in States.I bought it for much less money than what Accurate Locators used to sell it.
I discovered later on that probably this type of lrl doesn't work any more since most of the VLF stations arround Greece closed down.
Some other users here in Greece say that there are some emmisions in certain days but thats not a solution for me.
Even accurate locators made a Tx later and started selling it again until it was for some reason discontinued.
So I am in position now looking for a Tx to duplicate the emf fields of the old days that don't exist now.
But the truth is I always leave it behind J_P because I can not reach to a right conclusion of what is best to do.

I can put photos down of the cct or the pistol itself but I think somebody put some already in the forum under some other thread.Hi g-sani,
The way you describe the performance of the gold gun sounds similar to a radio direction finder. It sounds like it works by tuning the VLF signal from a distant transmitter that is no longer transmitting. How it can detect buried guns, I don't know. But if it needs a VLF signal to work, then this would explain why there were VLF transmitters manufactured to make a new VLF transmission after the VLF transmitter was shut down.

From what you posted, I would think you first need to determine what frequency the gold gun is tuned to (I think I remember it is somewhere around 60KHz). You may be able to send an email to the company that sold the transmitters, and ask what frequency they are. Then you could build a transmitter that sends a VLF signal at this frequency to put near your treasure hunting area. I think WM6 can give some good information on how to do this.

Best wishes,
J_P

[Qiaozhi]

The Gold Gun has 3 ranges:


9.5KHz for long distance and weak EM fields.
26.7-27KHz for USA.
19.2KHz England, Philippines, Greece and USSR.

Or so they claim. :rolleyes:

[WM6]

If you were use a small transmitter at your hunting site, then the signal coming from this transmitter will be broadcasting RF in the near field, whose propagation properties are not the same as transmitters far in the distance.



Yes, but huge changing in propagation (like changing wave polarization etc) are in first line characteristic of very high frequency band as UHF not in VLF/ULF band. By local small transmitter we find some others aspect of problem. We are searching for weak source of reflected signal and at the same time we have in vicinity relative strong source of transmitted signal at the same frequency which cover weak target signal and disturb successive search . This is why I repeated that 0.3W is far enough and even too much for successive search. This is why we need as much as possible directive RX antenna to suppress direct TX signal in combination with some tricks and searching skill.

If we compare UHF and ULF frequency band from reflectivity view UHF are better to detect especially small target in air because of its directivity and worse to detect something underground because of his weak penetration ability, on other side ULF are weak on directivity and so worse to detect something in air but way better to detect something underground because of his excellent penetration ability in soil. Theoretically ULF radar can detect invisible objects (objects behind of hills or behinds of horizon) which UHF radar cannot. This is why ULF can reach targets on unusual way and why we speak about importance of RX sensitivity and Rx antenna directivity.

[g-sani]

I don't know what of instruments do you have in your lab.

If you start from "Gold gun" which is real for you, you need first to measure all of (as you say) three frequencies of your AL707. Do not believe to producers data it may vary, but because of ferrite antenna ("widest" Q) real data can be inside of acceptable tolerances.

There are some way to measure antenna resonance but first rule have to be that we may not to over-burden input LC circuit by direct measure instrument connection in a way to change his resonate frequency.

So we will try to measure without to over-lasting antenna circuit. Maybe you have or can lent some sort of reliable audio signal generator or signal generator for general use. If so, you first wind your testing transmit antenna from about 10 turns (1mm Cul) 10cm in diameter (or 10 turns on ferrite rods) and connect such testing antenna together with serial connected 1k pot (trim to middle position) to generator output. Put generator output on unloaded (max peak to peak output) square signal (typically 15vpp). Now you have your testing measurement transmitter ready.

Put your AL707 "ON" and approximate it to test antenna at about 20cm. Now you start to gradually change generator frequency from 0Hz to about 35kHz and watch for react from AL707 speaker or led. If you catch signal, try to establish his maximum. Frequency at which signal reach his peak is resonate frequency of selected frequency position of your AL707. Try the same way to establish other two frequency. In case of strongest signal from receivers speaker you can use attenuator on signal generator to get weak signal or put AL707 so apart from TX antenna to get weak signal from speaker. By weak signal we can more accurate establish peak and by this more accurate resonate frequency too.

In case of no signal from AL707 you can first regulate serial pot to lower resistivity of about 100E, more approximate test antenna to AL707 and at the end try to open it and measure signal at amplification stage by mV-meter or scope. To prevent possible damage hope that this would not be needed.

After you establish all three of antenna circuit resonate frequencies your next step is transmitter adopted to middle of three frequencies (or on one of his lower harmonics).

Here may you suggest to buy very usable testing instrument Portable frequency counter with possible use as field strength meter. You can search for it on eBay under name "GE FC-1 Portable Frequency Counter 10Hz - 2.6GHz". Usable to detect in-depended of transmitter and receiver resonate frequency of TX antenna and cheap.

Thank you very much for your help WM6.
The only thing that I have to ask you to explain me better is:

....After you establish all three of antenna circuit resonate frequencies your next step is transmitter adopted to middle of three frequencies (or on one of his lower harmonics). ....

Do you mean that if the lower freq. is 9khz and the higher is 10khz then the Tx must be adopted at 9.5Khz?

[J_Player]

Thank you very much for your help WM6.
The only thing that I have to ask you to explain me better is:

....After you establish all three of antenna circuit resonate frequencies your next step is transmitter adopted to middle of three frequencies (or on one of his lower harmonics). ....

Do you mean that if the lower freq. is 9khz and the higher is 10khz then the Tx must be adopted at 9.5Khz?Hi g-sani,
Look what Qiaozhi posted:

The Gold Gun has 3 ranges:


9.5KHz for long distance and weak EM fields.
26.7-27KHz for USA.
19.2KHz England, Philippines, Greece and USSR.

From this information, you need only one frequency for Greece to find the same VLF frequency you saw before.
19.2 KHz is the oscillator you want. This is much simpler than to build a variable frequency oscillator, and the antenna can be tuned for this frequency so it will send a strong signal at low power. Of course, you will want to make adjustments to find the exact tuning that gives good reception at your gold gun. See the WM6 post for this.

You could also build a transmitter that sends all 3 frequencies if you think this will help.

Best wishes,
J_P

[WM6]

Do you mean that if the lower freq. is 9khz and the higher is 10khz then the Tx must be adopted at 9.5Khz?



No, calculated middle frequency will be out of RX antenna resonance. We use real resonate frequency - one of three.

Exactly as J_P explain to you.

[g-sani]

ok I think I got it right this time.

[J_Player]

Yes, but huge changing in propagation (like changing wave polarization etc) are in first line characteristic of very high frequency band as UHF not in VLF/ULF band. By local small transmitter we find some others aspect of problem. We are searching for weak source of reflected signal and at the same time we have in vicinity relative strong source of transmitted signal at the same frequency which cover weak target signal and disturb successive search . This is why I repeated that 0.3W is far enough and even too much for successive search. This is why we need as much as possible directive RX antenna to suppress direct TX signal in combination with some tricks and searching skill.

If we compare UHF and ULF frequency band from reflectivity view UHF are better to detect especially small target in air because of its directivity and worse to detect something underground because of his weak penetration ability, on other side ULF are weak on directivity and so worse to detect something in air but way better to detect something underground because of his excellent penetration ability in soil. Theoretically ULF radar can detect invisible objects (objects behind of hills or behinds of horizon) which UHF radar cannot. This is why ULF can reach targets on unusual way and why we speak about importance of RX sensitivity and Rx antenna directivity.Hi WM6,
What you say about ULF radar is very interesting. ULF has a very large wavelength (many km) which makes it hard to image any small object from interference/reflection in the way microwave radar can. But the ground penetration is excellent for very large things. If you wanted to use RF to detect things in the ground, then VLF would be more suitable because the wavelength is shorter to allow better resolution of the buried object. As you increase the frequency, the resolution improves but the ground penetration is less. So a treasure hunter is looking for a frequency between the low and high that will have good ground penetration to maybe 1 meter, and good resolution to be able to locate where the anomaly is.

We know geologists use frequencies usually between 10-30KHz to map large rock fractures and ore deposits as well as fault lines. But they cannot find a buried coin 10 cm deep. Their signals are long wavelength that detect up to 25m deep in the ground or more.

But if we raise the frequency to 100 KHz, then the wave becomes shorter and will only penetrate to maybe 10 meters deep. At 250KHz, we expect even less depth, but better resolution of shallow targets.

My question is what is the best frequency you would consider for as treasure hunter who only wants to see to 1-2 meters depth maximum?
From the charts I look at, it seems that this may be very close to the lower AM broadcast band of 550 KHz.

Do you think an AM radio or modified AM radio at below 550 KHz could be used for looking at LF/VLF interference under the ground?
Also, is there a way to use these frequencies as a VLF radar?

Best wishes,
J_P

[WM6]

What you say about ULF radar is very interesting. ULF has a very large wavelength (many km) which makes it hard to image any small object from interference/reflection in the way microwave radar can. But the ground penetration is excellent for very large things. If you wanted to use RF to detect things in the ground, then VLF would be more suitable because the wavelength is shorter to allow better resolution of the buried object. As you increase the frequency, the resolution improves but the ground penetration is less. So a treasure hunter is looking for a frequency between the low and high that will have good ground penetration to maybe 1 meter, and good resolution to be able to locate where the anomaly is.

We know geologists use frequencies usually between 10-30KHz to map large rock fractures and ore deposits as well as fault lines. But they cannot find a buried coin 10 cm deep. Their signals are long wavelength that detect up to 25m deep in the ground or more.

But if we raise the frequency to 100 KHz, then the wave becomes shorter and will only penetrate to maybe 10 meters deep. At 250KHz, we expect even less depth, but better resolution of shallow targets.

My question is what is the best frequency you would consider for as treasure hunter who only wants to see to 1-2 meters depth maximum?
From the charts I look at, it seems that this may be very close to the lower AM broadcast band of 550 KHz.

Do you think an AM radio or modified AM radio at below 550 KHz could be used for looking at LF/VLF interference under the ground?
Also, is there a way to use these frequencies as a VLF radar?



As you say in this field we can find a lot of question and research possibilities that can lead to one of (for amateur) rare ways to get something like real RDL (Reasonable Distance Locator). Principle are simple, realisation not so.

To reach long distances it is allways better to use lower frequencies, because as we go higher more dissipation on earth surface occured. This is not only reason to go at lower frequencies, we amateur are limited by our experimetation to rare authorized frequencies for such experiments or we are out of law. So, for us, relative safe are EM wave experiments inside upper spectrum of audio frequencies, say abuot 20kHz.

For "about 20 kHz" frequencies we need only weak transmitter to reach huge distance because of very low surface dissipation. On other side weak transmitter do not push our very weak tracked signals "back to underground" from our antenna and cover it and false its direction by its own signal strenght. Distance propagation of those wavelenght not mean that we can detect something at miles and kilometers, as babbling scammers propaganda. No, we can discuss only about meters, provided that we build our devices so, that it is possible. Nor detection of single coin from distance of a meter or so is impossible under some circumstances (at first of coin orientation against directed Rx antenna). But at first we can locate by this method different underground metalic deposits and not small golden nuggets.

Additional hint: such "about 20 kHz" weak transmitter equipped with well build and tunned stacked vertical antenna we can put even in our backyard and search in circle on radiated terrain kilometers away from home equipped only with a receiver. In this case transmitter have to be weak as discussed yet and well adjusted to antenna to prevent disturb our neighbors by radiated harmonic interferences.

In general VLF wave are not less reflective from the same target (if we neglect diffraction) as UHF wave but are more dispersive in reflection so we get by multiple factor weaker signal from VLF reflection as by same ULF propagation. Reason more for sensitive receiver and extremly directive Rx antenna.

[Krzysztof]

Hi, WM6, J_player.
I have some ideas for discussion:
1. Tx antenna should be the characteristics of a vertical magnetic. For example, a low power 10mW may be an antenna coil structure feryt of basketball (max Q) upright position (at the high power nature ferytu turn into a piece of wire). Maybe some other magnetic antenna Slit (but size - it could be a bad idea) . I think that 1/4 lambda antenna or coil, has a large vertical leaf levels of radiation, and we do not want to receive the signal reflected from the surface only goal.
2. Can benefit from the popular timers 36kHz quartz and pure analog generator to minimize the distortion and
harmonics. Rx side, you can think of crystal ladder filter with the same X-tals
3. I think that AM 500 kHz bandwidth makes for great Skin effect (more superficial than deep). In addition, A3 gives random modulation signal strength at measurement. Any modulation of A1, A2, A3, A3A is amplitude modulation, which forces a large measure of time - averaging.
4. How about an antenna Tx / Rx Framework 1m x 1m placed horizontally 20cm above ground level to eliminate the capacity of the soil (detuning) and reduced mutual visibility (direct reception)
5. Do you not think that we are moving close to the technology 50 years ago and described by Mikebg in this forum?
Vy 73 Chris

[WM6]

Hi Krzysztof,

thanks, I think your ideas are worth to be seen.

Can you go a little further according your ideas and post here some graphic presentation of your ideas and maybe some schematic or diagrams?

Yes, we are talking about an old radio communication technology as mikebg rediscover it too, but if it work all is ok.

It work if proper builded and used, and, as we can see, even used by modern army in different way.

[Geo]

Hi, WM6, J_player.
I have some ideas for discussion:
1. Tx antenna should be the characteristics of a vertical magnetic. For example, a low power 10mW may be an antenna coil structure feryt of basketball (max Q) upright position (at the high power nature ferytu turn into a piece of wire). Maybe some other magnetic antenna Slit (but size - it could be a bad idea) . I think that 1/4 lambda antenna or coil, has a large vertical leaf levels of radiation, and we do not want to receive the signal reflected from the surface only goal.
2. Can benefit from the popular timers 36kHz quartz and pure analog generator to minimize the distortion and
harmonics. Rx side, you can think of crystal ladder filter with the same X-tals
3. I think that AM 500 kHz bandwidth makes for great Skin effect (more superficial than deep). In addition, A3 gives random modulation signal strength at measurement. Any modulation of A1, A2, A3, A3A is amplitude modulation, which forces a large measure of time - averaging.
4. How about an antenna Tx / Rx Framework 1m x 1m placed horizontally 20cm above ground level to eliminate the capacity of the soil (detuning) and reduced mutual visibility (direct reception)
5. Do you not think that we are moving close to the technology 50 years ago and described by Mikebg in this forum?
Vy 73 Chris

Hi Chris.
Do you mean something like the photo???

Regards

[Krzysztof]

Hi all.
Modest note attached.

Unchecked idea is to use my Fluxgate magnetometer as an Rx!
Always treated the VLF and the other as EMI, now you look at it differently.
Tx antenna gives the issue a magnetic field, propagated in the ground, when it is sufficiently stronger than the earths magnetic field in conjunction with GPS and "Vumate" or "Snuffler" we are better than many well-known German company.:rolleyes:
Who else will join the storm drain?
Vy 73 Chris

[Krzysztof]

Hi Geo.
It looks like a mini two-box.
And I think the 2 antennas with a vertical magnetic polarity, the land
component preferably disperses component magnetic field the electromagnetic field.
Maybe someone is thinking of something better than the ferites
antenna.
Vy 73 Chris

[WM6]

Hi Geo,

you are main developer here. Are you done some test?


Yes Krzysztof, it is more clear to me now, what you suggest.
Except draving Ad.4: did you imagine RX or TX coils as a fixed scaning or mobile?

[g-sani]

It seems to me that many of you here know the tips to build an LRL using rf (Tx and a Receiver to go on target)
This theory is already proved that it works and all you electronics should have one ready in your home for your treasure hunting expeditions.
Instead of that you are looking for other ways of building LRLs when you never had any treasure discovered yet.
Forgive me but I don't understand you.
I remember Esteban said that it is working and I think also he put a very old pfoto somewhere of people using it back in the late '30s.
Well I will put it down again.
I used to owe once something like that and I said it before in some other thread that it was working allright.Some people don't believe me but what can I do about that.
I said to Geo that sometime I will give him the Rx(which I still have) to see if we can make a suitable Tx so to make it work again.
You see we placed it once underneath a tree and we took the Rx and went a bit far from the transmiter while trying to spot a target.It was raining heavily some hours before and water drops was coming down from the leaves.The result was a short circuit at the Tx and it stopped working.We sent it for service but...
They sent us a different LRL back telling us that they could not repair the Tx.I loved that LRL and I was upset when we received back a different one.
Anyway, this one works as well but now you have to be a bit of a dowser to go on target.
To tell you the truth I wouldn't mind of paying some money again for such an LRL and if anybody knows anything in the market please let me know.
Does anybody knows if MAGNACAST™ 5000 FORWARD GAUSS Metal Detector™ works on the same principle?

http://www.vernellelectronics.com/productinfo.htm#5000

[mikebg]

AL707 and AL718 are very primitive and imperfect compared to EM16 of Geonics, because they have no a second ferrite rod antenna for reference signal. The operating principle of EM16 is described in patent US3500175.

[WM6]

Instead of that you are looking for other ways of building LRLs when you never had any treasure discovered yet.
Forgive me but I don't understand you.


When, in disgrace with fortune and men's eyes,
I all alone beweep my outcast state
And trouble deaf heaven with my bootless cries
And look upon myself and curse my fate,
Wishing me like to one more rich in hope,
Featured like him, like him with friends possess'd,
Desiring this man's art and that man's scope,
With what I most enjoy contented least;
Yet in these thoughts myself almost despising,
Haply I think on thee, and then my state,
Like to the lark at break of day arising
From sullen earth, sings hymns at heaven's gate;
For thy sweet LRL remember'd such wealth brings
That then I scorn to change my state with kings.

Willy Shake (S.29)

[Seden]

MikeBG,

This is true. What I would rather use is an active antenna to pick up the reference signal and compare the phase of the ref. signal with the signal from the horizontal loop over the treasure or ore. Another idea that I've seen in Magnetotelluric patents is to observe spectrum in the audio range when you are over ore deposits. For treasure you would use higher frequencies to see the smaller objects. In lieu of that you could use a white noise generator to do the same with much better S/N for the same spectrum signature of different metals or ores.

Randy

[Krzysztof]

Hi of all.
I don't think so , that we're to clear forums as well bids of unfamiliar utilization present techniques not abnegating sie the old man vets. Yourselves ain't dowser , Respect those regular people whereas not swindler.
I not know gold gun , I think not , everybody they've entrance into nich as well wherefore bids of unfamiliar coinage DIY.
J_Player g_Sani.
To be sure best antenna is not they've big storing magnetically clearing switch pawn as well least radiation electricians over world ; 60 years before the communication was done ex antenna underground on figures 2 probes tributary margin ex generator engine-room undersized frequency communication (besieged troops ).
Wherefore coinage ex signal electric ex generator Tx until world is not worst.
J_Player.
Zone LF this dubious coinage. Exemplary transmitter Monte Carlo (225kHz, 200kW) premises (interference) transmitter Warsaw (227kHz, 1MW) heard on Nand France free past distances upwards of 1000km to automotive receiver wireless.
Wave worldly-minded superficial is not large what prompts breaking signal aims.
Yesterday wrong frequency quartz ex timepieces duty be 32768Hz.
I don't think so , that Tx generator to quartz 32kHz at least on often Tx clearing us ex the rubs and worries of life of stability.
WM6.
Account spool Rx clear mobil until scaning. Spool blanket 1m x 1m will correspondent , not refutes of utilization spools on the lines of MD average 30 - 40 cm , whereas depths yet never mind.
Receiver tenderheartedness 1 mikroVolt ex strait zones ex such quartz on strained serial duty be gross on hand.
Yourselves deal to spring coinage ex Rx on figures gradiometers fluxgate ( tenderheartedness some nT/m )- this so-so promisingly.
At least once EMI will be utilization. ;)
Bids until tendering your coinage.
Best regards. Vy 73! Chris.

[J_Player]

It seems to me that many of you here know the tips to build an LRL using rf (Tx and a Receiver to go on target)
This theory is already proved that it works and all you electronics should have one ready in your home for your treasure hunting expeditions.
Instead of that you are looking for other ways of building LRLs when you never had any treasure discovered yet.
Forgive me but I don't understand you.
I remember Esteban said that it is working and I think also he put a very old pfoto somewhere of people using it back in the late '30s.
Well I will put it down again.
I used to owe once something like that and I said it before in some other thread that it was working allright.Some people don't believe me but what can I do about that.
I said to Geo that sometime I will give him the Rx(which I still have) to see if we can make a suitable Tx so to make it work again.
You see we placed it once underneath a tree and we took the Rx and went a bit far from the transmiter while trying to spot a target.It was raining heavily some hours before and water drops was coming down from the leaves.The result was a short circuit at the Tx and it stopped working.We sent it for service but...
They sent us a different LRL back telling us that they could not repair the Tx.I loved that LRL and I was upset when we received back a different one.
Anyway, this one works as well but now you have to be a bit of a dowser to go on target.
To tell you the truth I wouldn't mind of paying some money again for such an LRL and if anybody knows anything in the market please let me know.
Does anybody knows if MAGNACAST™ 5000 FORWARD GAUSS Metal Detector™ works on the same principle?

http://www.vernellelectronics.com/productinfo.htm#5000Hi g-sani,
The Magnacast 5000 is said to be an AM transmitter using a loop antenna to send a signal to one side. Then a second small receiver loop is held in the hand to locate the hidden metal. I heard no information to show that the Magnacast 5000 works, or not works. You can only know by trying it to see. Forward Gauss does not mean anything. No electronics engineer or scientist has ever heard of forward gauss. It does not exist. This is only a word made by the manufacturer to make it sound like it is new technology. Also, I do not believe you will find multiplexing circuits inside this detector like the manufacturer claims. But I don't know for sure.

I would not spend money for this detector unless you see it finds hidden treasures first. The other detectors built by VR Electornics are believed to fail for finding treasure. Even Dell Winders said "...operating conditions deteriorated affecting the reliability of the instrument making it impractical for my use in 1988".

You can read more about the Magnacast 5000 here, where Dell Winders posts false information and tries to hide the truth about forward Gauss: http://www.geotech1.com/forums/showthread.php?t=13089

Best wishes,
J_P

[Geo]

Hi Geo,

you are main developer here. Are you done some test?


Yes Krzysztof, it is more clear to me now, what you suggest.
Except draving Ad.4: did you imagine RX or TX coils as a fixed scaning or mobile?


Hi WM6,

I made it before 2... 3 years. I tested but i had problems. It had the ability to detect a big object at 30m but it was very sensitive North horizon, at distance between me and detector and from trees.
So i let it at the side :lol:.
Maybe at lower frequency to work better .... who knows.
I don't remember sure, but i think that it worked at about 800Khz.

Regards:)

[Krzysztof]

Hi Geo.
It issues me, that secret sticks (lie) in (to) in antenna with vertical magnetic polarization.
So as vertical feryt, we search something better.:p
And f max< 32kHz.
Vy73 Chris.

[WM6]

Hi WM6,

I made it before 2... 3 years. I tested but i had problems. It had the ability to detect a big object at 30m but it was very sensitive North horizon, at distance between me and detector and from trees.
So i let it at the side :lol:.
Maybe at lower frequency to work better .... who knows.
I don't remember sure, but i think that it worked at about 800Khz.



Geo, are you tried to put your ferrite antenna in RFI protective housing made from can of beer (one side open) and connected to ground of oscillator?

[g-sani]

Hi g-sani,
The Magnacast 5000 is said to be an AM transmitter using a loop antenna to send a signal to one side. Then a second small receiver loop is held in the hand to locate the hidden metal. I heard no information to show that the Magnacast 5000 works, or not works. You can only know by trying it to see. Forward Gauss does not mean anything. No electronics engineer or scientist has ever heard of forward gauss. It does not exist. This is only a word made by the manufacturer to make it sound like it is new technology. Also, I do not believe you will find multiplexing circuits inside this detector like the manufacturer claims. But I don't know for sure.

I would not spend money for this detector unless you see it finds hidden treasures first. The other detectors built by VR Electornics are believed to fail for finding treasure. Even Dell Winders said "...operating conditions deteriorated affecting the reliability of the instrument making it impractical for my use in 1988".

You can read more about the Magnacast 5000 here, where Dell Winders posts false information and tries to hide the truth about forward Gauss: http://www.geotech1.com/forums/showthread.php?t=13089

Best wishes,
J_P

This is what I thought to be J_P.The rest of their detectors have nothing special to show.
Of course the same thing applies here.Try it yourself to get knowing the truth, as always.
Regards, g-sani

[g-sani]

When, in disgrace with fortune and men's eyes,
I all alone beweep my outcast state
And trouble deaf heaven with my bootless cries
And look upon myself and curse my fate,
Wishing me like to one more rich in hope,
Featured like him, like him with friends possess'd,
Desiring this man's art and that man's scope,
With what I most enjoy contented least;
Yet in these thoughts myself almost despising,
Haply I think on thee, and then my state,
Like to the lark at break of day arising
From sullen earth, sings hymns at heaven's gate;
For thy sweet LRL remember'd such wealth brings
That then I scorn to change my state with kings.

Willy Shake (S.29)


Nice poetry WM6 but I never herad of Willy Shake.
Was it a treasure hunter as well? :lol:
Not a dowser anyway!

[WM6]

Nice poetry WM6 but I never herad of Willy Shake.
Was it a treasure hunter as well? :lol:
Not a dowser anyway!

You do not know this old rocker? Probably you are too young.

Yes I think it was a biggest dowser ever, look at the penultimate verse.

[Geo]

Hi Geo.
It issues me, that secret sticks (lie) in (to) in antenna with vertical magnetic polarization.
So as vertical feryt, we search something better.:p
And f max< 32kHz.
Vy73 Chris.

I don't understand what you are saying about!!!

[Geo]

Geo, are you tried to put your ferrite antenna in RFI protective housing made from can of beer (one side open) and connected to ground of oscillator?

Hi WM6,
No... i did not tried to make anything with ferrite. The only that i did was a replacing of ferrite with a simple bigger coil, with the same problems....

Regards:)

[g-sani]

You do not know this old rocker? Probably you are too young.

Yes I think it was a biggest dowser ever, look at the penultimate verse.

Yes,I think he must have been lucky at least once discovering treasure so he knows how sweet it is. :lol: :lol: :lol: :lol:

[Krzysztof]

Hi Geo.
Forgive my English, I have different translators, none technical.
To new idea the best magnetic aerial is needed to Tx, for good irradiating the area. Best if only the entire energy went to one's grave as the magnetic component, Tx Energy radiated by the area is completely unnecessary and harmful.
I am looking for something better than the ferrite vertical antenna in my memory and good books. I want energy fields 10 - 100 miliwat of the radiation. And ferrite will already be then too weak.
He is staying to bury to the earth frame antenna. Other idea of the antenna, can stick 2 probes to the earth, and made Tx in the B class push-pull. GND connect with 3rd probe.
A few attempts I will make in spring.:cool:
Best regards Chris.

[Seden]

Chris,

You are correct, the ground antenna is the best of all. This is something I will be working with as well. In my books on VLF, a top loaded vertical with a big capacity hat would be 2nd best but you still have to supply lots of ground radials for it to be efficient. I have been talking to another Amatuer Radio Operator on 1853.5 KC for 25 years using Single Sideband so I know from first hand experience what makes a good LF antenna.

The ground antenna does not work as good at the upper end where I work(L.F.). Ground Antennas work good below 50KC. Make sure you space your ground rods as far from pole to pole as you plan to walk around.

Randy

[g-sani]

..Other idea of the antenna, can stick 2 probes to the earth, and made Tx in the B class push-pull. GND connect with 3rd probe.
A few attempts I will make in spring.:cool:
Best regards Chris.


I believe thats more comfortable for the treasure hunter.
And from one point of view is more practical even for the electronics engineer while having a major problem solved.
When it comes to the gold gun sold whith a transmiter the electronics designer prefered sending the signal direct into the earth using probes.
;) ;)

[J_Player]

... the ground antenna is the best of all. This is something I will be working with as well. In my books on VLF, a top loaded vertical with a big capacity hat would be 2nd best but you still have to supply lots of ground radials for it to be efficient. I have been talking to another Amatuer Radio Operator on 1853.5 KC for 25 years using Single Sideband so I know from first hand experience what makes a good LF antenna.

The ground antenna does not work as good at the upper end where I work(L.F.). Ground Antennas work good below 50KC. Make sure you space your ground rods as far from pole to pole as you plan to walk around.

Randy Hi Randy,
If a person wanted to build a ground antenna to operate at 30 KHz, what actual hardware materials and sizes do you recommend he should he use for this antenna?

Would the apparatus for a treasure hunter's portable field antenna be significantly different than what you would recommend for a permanent installation used in communications?

Best wishes,
J_P

[WM6]

When it comes to the gold gun sold whith a transmiter the electronics designer prefered sending the signal direct into the earth using probes.

;) ;)

g-sani, antenna have to be in resonance to be effective. By such design with two to TX wired probe, you never reach resonance and antenna efficiency is very very low (except in way to burn transmitter).

Properly grounded and resonate tunned antenna on ULF/VLF band is at the same time ground and air antenna and with way better propagation, because we are speaking here about wave reflection and not about eddy current induction.

[Seden]

JP,

In the reports I've read from the Amatuer Op's in Europe operating at 73K.C.'s, a ground rod as short as 18" seems to work out well and you can resonate and impedance match a ground antenna by the way. A Google search using 73khz amatuer band will get you lot's of hits.

For a permanent home setup I much prefer the 8' copper rods used for grounding home electrical systems to give me more cross sectional area which decreases the resistance obviously and less susceptible to variations in soil conductivity via drying out in the summer heat.

Works for me.

Randy

[WM6]

seems to work out well and you can resonate and impedance match a ground antenna by the way.



Randy, those "impedance match" work with resistive component of soil. Nothing to do with resonance of antenna (Q are practically nonexistent). This is only additional antenna load that maybe help to not burn TX output transistor.

[Seden]

WM6,

You may be right as so far I have never made one, just read about the Amatuer's experiences.

Well then it's top loaded vertical with MANY ground radials and a large capacity hat. Yeah it can be done in the field with some guy wires,maybe buy the portible antenna setup the military uses that are sold to Amatuer Ops for field day operation.

Randy-WD6ELU

[mikebg]

Hi Geo.
It looks like a mini two-box.
And I think the 2 antennas with a vertical magnetic polarity, the land
component preferably disperses component magnetic field the electromagnetic field.
Maybe someone is thinking of something better than the ferites
antenna.
Vy 73 Chris
Chris, this is done 50 years ago for prospecting. For induction balance and to suppress GND signal from soil surface, ferrite rods are not exactly perpendicular.

[Geo]

Hi Geo.
Forgive my English, I have different translators, none technical.
To new idea the best magnetic aerial is needed to Tx, for good irradiating the area. Best if only the entire energy went to one's grave as the magnetic component, Tx Energy radiated by the area is completely unnecessary and harmful.
I am looking for something better than the ferrite vertical antenna in my memory and good books. I want energy fields 10 - 100 miliwat of the radiation. And ferrite will already be then too weak.
He is staying to bury to the earth frame antenna. Other idea of the antenna, can stick 2 probes to the earth, and made Tx in the B class push-pull. GND connect with 3rd probe.
A few attempts I will make in spring.:cool:
Best regards Chris.

Hi Chris.
The idea of the probes to the ground is not good if you want to use the detector as mobile detector and not as "constant".
For vertical antenna a simple spiral antenna is a good solution. I worked with a similar one

Regards:)

[WM6]

Chris, this is done 50 years ago for prospecting. For induction balance and to suppress GND signal from soil surface, ferrite rods are not exactly perpendicular.



Hi mikebg, those are aldest model, newest are some different:

"Transmitter and receiver dipole orientations of the EM38-DD and DUALEM-1S (instruments are oriented parallel to the surface). The loops of wire form a solenoid and a dipole is created when current passes through the wire. The EM38-DD (top) has its transmitter and receiver dipoles oriented in horizontal–horizontal (H–H) and vertical–vertical (V–V) modes. The DUALEM-1S (bottom) also uses a V–V and a vertical–horizontal (V–H) mode for the dipoles in its transmitter and receiver."

The 4 most common types of EMI instruments, are the EM38, EM31, EM34 and EM39. Although they all operate the same, they vary in the depth to which they read within the soil profile. All operate in both the vertical and horizontal mode (this determines the depth to which they read). A summary of this is given below:

EM38 - vertical mode (1.5m) horizontal mode (0.7m)
EM31 - vertical mode (6.0m) horizontal mode (3.0m)
EM34 - 6.0m to 60.0m
EM39 - used for logging down boreholes.

These depths are only indicative, as the depth of penetration of the electrical signal will be determined by the uniformity, or non-uniformity, of the soil. If the soil is very conductive near the surface then the signal will be dissipated and will not read to a greater depth.

[Krzysztof]

Inventors hello to all.
My humble figure.
Sed.Probes the ground in a triangle to have a concentric radiation underground.
Geo. I think that each antenna will sow the ground surface wave. Im only interested in measuring the electromagnetic wave Reflected from the underground treasure with a very sensitive receiver. Narrowband = 100Hz max. Low noise. Sensitive = 1mikroVolt. There may be a vertical antenna ferite.
Micebg. I know the history of art, now I go to do already without fear.Do private mini-VLF radio station located in a fixed location and look at neighborhood.
I look forward to constructive criticism.8)
Best regards

[Geo]

Hi Chris
I agree that the treasure will influence the radiated energy (it will grow her or it will minimize). This will become perceptible with receiver above the treasure. However how we will take a "line" with the receiver from the point where we found itself, up to the point of treasure???

Regards:)

[Krzysztof]

Hi Geo.
It does not interest line of completely.
I. it touches it only Tx as lighting lamp Signal grows over purpose according to statistic schedule Gaus. Good narrow receiver wanted only.
It touches it technical colleges it LRL but it not twig, I am technocrat only. :(

Best regards Chris

[mikebg]

WM6,
The device in posting # 64 is model APEX MKI. It is like Geonics
EM15, designed by Vaino Ronka.
Chris,
1. Target signal at metal detecting seems as modulated TX signal with frequency spectrum from 0,1Hz to maximum 6Hz. That means we need RX having bandwidth no more than 12Hz. More bandwidth means more noise. There are sensitive metal detectors operating with bandwidth 4Hz only. We need automatic digital filtering to achieve stabile narrow band receiving. Bandwidth 100Hz means 5 times more noise relative to bandwidth 4 Hz.
2. The modulation index of target signal is very small because RX receives two large signals AIR and GND having the same frequency. If you wish to detect target signal 1uV, but AIR and GND signals are 10mV, then the modulation index is 0.0001. We need suitable automation to increase the modulation index by suppressing AIR and GND signals. However if you swing search head one or two times pro seconde, the GND signal will be modulated by frequency 1 or 2Hz. This is in target spectrum.:frown:
3. We need reference signal for synchronous demodulation. For example, Vaino Ronka uses AIR signal from second RX antenna as reference signal. To demodulate weak signals,we should use GND signal as reference.
4. Your TX antenna is absolutely inefficient becase has only one small turn. Read for TX antennas and loop used in metal detecting in site www.geonics.com (http://www.geonics.com)

[WM6]

The device in posting # 64 is model APEX MKI. It is like Geonics EM15, designed by Vaino Ronka.



Thank you mikebg, APEX is not known to me. I think it was EM15.



However if you swing search head one or two times pro seconde, the GND signal will be modulated by frequency 1 or 2Hz. This is in target spectrum.:frown:



Not only ULF modulation because of swinging, but because of handshaking too, a lot of parasitic modulations that suppress target signal.

[Seden]

Chris,

Go to Google and type in TURAM system. In this you transmit the signal into the ground via ground rods and you have 2 separate coils for the receiver that goes into a phase detector. The coils are separated just like a two box detector and so when you the lead coil passes over the ore body or treasure chest you will get a phase difference. This saves having to have to separate receivers,one to get the air signal for reference and the other for the ground signal. The air signal is ALWAYS the reference as the ground signal is where you are looking for a change due to whatever's buried that's big enough to change the phase in the ground signal.

Randy

[Krzysztof]

Hi Mikebg.
You are absolutely right. I have past experience in the construction of an amateur on the 4MHz filter ladder with 100Hz bandwidth and less. At 32kHz easily get smaller bandwidth, the more crystals are exactly the same watch. What about modulation A2 ?
Vaino Ronk AIR uses second RX signal from antenna as reference signal , a brilliant idea + todays software that gives a strong instrument.
I hoped to check the simplest method. Lighting treasure chest only to the GND, a simple receiver - preferably with a vertical antenna ferite. Then I have a minimum of receipt by the AIR and directional reception of the order. SPECTRUM LAB is the program straight from the VLF.
Ideally, it was simple, easy and fun, small and cheap. Perpetium mobile not yet.8)
Is this a useful?
http://www.stormwise.com/page28.htm
Best regards

[Krzysztof]

Hi Seden.
Do you have a good illustrated examples to seek treasures TURAM system? With Google is a lot of rubbish and a narrow scientific publications for money.:frown:
Turam is perfect for the geology of ore. Engineering phase is interesting that the resolution can be obtained. There is a lot of redundant data - You will need a smart program.
If it were available for advanced amateurs will be interesting to face this.:rolleyes:
It affects everything VLF, I found something similar:
http://www.eos.ubc.ca/ubcgif/iag/foundations/method-summ_files/vlf-notes.htm
Consider the last sentence!
Best regards. Chris

[Seden]

Chris,

That was an excellent article on the VLF system and yes the last sentence was interesting. So now we're back to an inductive antenna if I read that correctly. In "Mining Geophysics" TURAM is used strictly for Ore bodies but that's what the book is all about.

As I mentioned earlier in this book a HORIZONTAL ~24" Ferrite bar mounted on a tripod as well as a 15'per side wire loop were used for VLF type of exploration. I would try the large diameter 24" ferrite as they can handle some wattage (as I have experimented on 183.5 K.C. with successfully). The ferrite bars are not prone to saturation as easily as a ferrite torroid which can be verified with the formulas.

For the reference signal here in the US I would use the little 400 MHZ transmitter-receiver boards that are so inexpensive.

Randy

[Krzysztof]

Hi Seden.
In me there is no kimberlit or black sand or pebbles gold. :angry:
For the moment I'm finishing 3 version of the gradiometer to the residues after the war and archaeological surprises. :rolleyes:
Little transaiwer 400MHz is why?
VLF At small slip.:(
Best regards Chris.

[epitopios]

I believe thats more comfortable for the treasure hunter.
And from one point of view is more practical even for the electronics engineer while having a major problem solved.
When it comes to the gold gun sold whith a transmiter the electronics designer prefered sending the signal direct into the earth using probes.
;) ;)

watch at this:
20.3 kHz
ICV, Tavolara, ITALY, 20kW ERP (or 100kW?).
Oct./99 1015 received by DG4BAS in msk


the nearest strong radio signal for you and me !!!

maybe it will help you !!!!
friendly , epitopios

[WM6]

watch at this:
20.3 kHz
ICV, Tavolara, ITALY, 20kW ERP (or 100kW?).
Oct./99 1015 received by DG4BAS in msk


the nearest strong radio signal for you and me !!!

maybe it will help you !!!!
friendly , epitopios


Some different data:

ICV 20.27kHz Tavolara (Italia)

ICV 20.76kHz Tavolara (Italia)

[g-sani]

watch at this:
20.3 kHz
ICV, Tavolara, ITALY, 20kW ERP (or 100kW?).
Oct./99 1015 received by DG4BAS in msk


the nearest strong radio signal for you and me !!!

maybe it will help you !!!!
friendly , epitopios


Thanks for the tip epitopios but is it a time table of transmition of this station?
I believe that they only transmit certain hours.

[Ernie]

Dear who ever

Re: This is a LRL/Remote sensing thread. Your article relates to a SAMPLE NOTHING TO DO WITH REMOTE SENSING. Could you please take this dissussion elsewhere via Carl

kind regards and happy prospecting

Ian (ERNIE) Parker

[WM6]

Dear who ever

a SAMPLE NOTHING TO DO WITH REMOTE SENSING.

Ian (ERNIE) Parker

Hi Ernie which SAMPLE?

Who assessed what LRL is and what LRL is not, and under which criteria?

Have you met Mr hung today?

Happy long range locating to you.

[Ernie]

FROM THE THREAD LINK - A new type of magnetic field detection system, which can operate at a frequency below 1 kHz, is proposed and developed. The system consists of a 40-turn-coil to generate the magnetic field and a magneto resistive sensor to detect both the amplitude and the phase signal of the magnetic field induced by eddy-current and magnetization of the samples. The magnetic field detection of ferro- and non-magnetic samples using the system is demonstrated and discussed.

There you go my special needs buddy, SAMPLE, come on now you say it, SAMPLE. WELL DONE, these tests are carried out in a uni lab, no long distance across location. Because these are done in a class room with a SAMPLE.

If you do not understand what a SAMPLE is please reply back and i will spend some more time with my special needs buddy.
kind regards and happy prospecting

Ian (Ernie) Parker


Keywords

[Krzysztof]

Honourable ERNIE.
The experts on this forum express in majority with electronics of, geophysics, interdisciplinary.
They are here surely and followers LRL, though they have not psychophysical abilities - no became Rockefeler.
Colleague is here also, which examples about "gold gun" and LRL numbered several thousand fasts.
I ask, do not go with this road, to to enlarge the quantity of fasts have protested for several days only - derange discussion.:(
You are in subject of new ideas and new technologies - propose something interesting also - nobody will mock you.
You in library will find out, that the method the geophysics (in this VLF) the using advanced techniques of looking for deposit the kimberlit of, gold, of iron ... they are for geologists commonplaceness.
Here interested they look for straight lines of methods the chests of treasure would find - every giving effect method is admissible.
Nobody likes paying for miraculous black cases but fraud (new LRL).
Boast with your construction we - invite.:)
Best regards Chris

[Seden]

Well said Chris! We are not fools but men of experience sharing together our knowledge.

Randy

[g-sani]

I agree that sometimes we take different paths in our search of a new detecting method.
Then we realise that everything is related and then we leave that aside and we focus again to what the thread is suppose to be.
I believe it is a common thing happening in all forums but it is also a good thing that somebody is there to remind us where we are or where we were suppose to be.:D

[gold24h]

From my understanding the gold gun is a receiver that measure signal strength,the signal strength showing on the meter.Metal long time burried objects would absorb low frec. raidio transmission,so when you point the gun towards the treasure you would have a drop or null in signal strength,that is how it works,i hear it works great for large objects or natural gold and silver deposits but not very well on small targets like a coin.I beleive it works but needs to be modified for smaller targets.

[g-sani]

I will tell you an example of something that I know for sure to get an idea.
I believe that the gold gun has the ability to separate between different materials.Sound compared to meter readings can give you discrimination.
There are people that mastered it through practice.The designer and the maker just put down the idea and they never bothered testing it properly.
Here is an example of what has been found out from some users and I can verify it as well.
Whenever you point the Goldgun to a place that pieces of ceramics are burried you will have always the same sound coming out of it.
It is like having a very hot piece of metal putting it inside a pan full of water.You hear a sound that lasts as long as it takes for the metal to cool down and it has always the same characteristics.
It starts loud and sharp and it goes off gradually, usually it takes 1-2secs for the whole sound to dissapear.;)

[gold24h]

Very interesting,i wonder if the ceramic had metalic glazes on it,a lot of the glaze used on ceramics is made up of metalic oxides.I beleive a similer device that works like the gold gun could be built,maybe by using a transmitter for the background signal would make a very good machine.The transmitter would need to be away from the search area.

[ALEX.356]

Dear G-Sani ,
kindly clarify about ceramics. What quantity are you talking about.
In kgs.
Clays [not glazed] contain 8% Fe2O4 Iron oxide. Which is a lot.
But for the gold gun to respond it must be a big mass of them [ I suppose].

Kind regards,

ALEX.356.

[g-sani]

Dear G-Sani ,
kindly clarify about ceramics. What quantity are you talking about.
In kgs.
Clays [not glazed] contain 8% Fe2O4 Iron oxide. Which is a lot.
But for the gold gun to respond it must be a big mass of them [ I suppose].

Kind regards,

ALEX.356.

Yes it was a big mass of them but don't be sily I can not talk for their weight in kilos.
Because some of these places I have checked them a long time ago whith my old pulse detector which suffered from these pieces of ceramics showing them as a target(SUPERSCAN MKI) I can tell you this.
It is pieces of ancient ceramics from broken vases and also tiles from ancient houses they are in all different sizes(the biggest are about 20*20 cms) but also in different depths and in most cases they cover an area of a few square meters.
I don't think the GG can detect small objects but I know for sure that it can detect big ones.Well where I live somebody needs to use a transmitter now since the VLF transmitions from nearby stations are stopped.It is one station(ICV) transmitting from Italy but then not always.
To tell you the truth I am not using my gg any more but I am in search of the right way and the right transmitter to provide the neccessary signal to the area in search.
People in electronics say that it can be made easily but their opinions differ in many things such as the aerial to be used etc etc.....

[wam]

Hi, I just tried Hot Wheels Radar Gun.
I got it for $2 from Sunday market. It is a “toy” to measure speed of slot cars or other toys. The super thing is that it operates at 10.525GHz, it has digital display showing 3 digits representing speed. For curiosity I checked it on 50c coin. When I have moved speed gun slowly over the coin it displayed number over 30 for a second. It does it every time up to about 80 cm distance in the air.
Then I have placed coin underground about 10 cm and moved speed gun about 5 cm above ground – it was the same result when passing over the coin. It works.
I see some of them on ebay for around $30 (used one must be much less).
Did one make some experiments with this toy – like modified reflecting part or so.
I checked the wire with signal from the head with oscilloscope and it goes up and down while object displaces location in the front but the number is produced only when DC level varies fast enough – so it is possible to sense object even in static condition if CRO or DC volt meter is connected to wire “SIG” from PCB.
I will make more testing – any comments?

[Locator]

Επιτοπιε μ'αρεσε το αβαταρ σου..σωστος!!!

I like the avatar of you epitopios:)

[Ernie]

Hi, I just tried Hot Wheels Radar Gun.
I got it for $2 from Sunday market. It is a “toy” to measure speed of slot cars or other toys. The super thing is that it operates at 10.525GHz, it has digital display showing 3 digits representing speed. For curiosity I checked it on 50c coin. When I have moved speed gun slowly over the coin it displayed number over 30 for a second. It does it every time up to about 80 cm distance in the air.
Then I have placed coin underground about 10 cm and moved speed gun about 5 cm above ground – it was the same result when passing over the coin. It works.
I see some of them on ebay for around $30 (used one must be much less).
Did one make some experiments with this toy – like modified reflecting part or so.
I checked the wire with signal from the head with oscilloscope and it goes up and down while object displaces location in the front but the number is produced only when DC level varies fast enough – so it is possible to sense object even in static condition if CRO or DC volt meter is connected to wire “SIG” from PCB.
I will make more testing – any comments?


Hi WARM Try going to Colorado gold sticks thread 14 You might find the answer there - happy prospecting - Ernie

[Black Cloud]

Hi WM6, et al. I have an EMFAD which was designed to receive 44-142khz from the "submarine" tx's, and we all know that the old Loran and Omega stations have shut down, leaving the 3 here in the USA, which transmit at around 24khz. Fine. So, first I had the EMFAD receiver altered (caps) to receive a very selective 24khz signal, and then I had a small tx built (North Country Radio) that supposedly puts out 1 watt. I have attached a 12 mtr x 4 sides loop antenna (18 guage copper stranded wire) to it but it does not produce enough power to give steady constant results on my imagry. The side closest to the tx is always much stronger, so not a reliable image is produced when I do my grid survey. Any ideas? I would have thought that the tx in Cutler, Me would have been strong enough to reach down here in south Texas, but it doesn't seem to be. TIA for any advice.
Also, the manufacturer uses similar tx in his new model, the "PRO" and he advised me on the antenna design.

[g-sani]

Επιτοπιε μ'αρεσε το αβαταρ σου..σωστος!!!

I like the avatar of you epitopios:)

I think he is proud to be Greek as well. ;)

[WM6]

Hi WM6, et al. I have an EMFAD which was designed to receive 44-142khz from the "submarine" tx's, and we all know that the old Loran and Omega stations have shut down, leaving the 3 here in the USA, which transmit at around 24khz. Fine. So, first I had the EMFAD receiver altered (caps) to receive a very selective 24khz signal, and then I had a small tx built (North Country Radio) that supposedly puts out 1 watt. I have attached a 12 mtr x 4 sides loop antenna (18 guage copper stranded wire) to it but it does not produce enough power to give steady constant results on my imagry. The side closest to the tx is always much stronger, so not a reliable image is produced when I do my grid survey. Any ideas? I would have thought that the tx in Cutler, Me would have been strong enough to reach down here in south Texas, but it doesn't seem to be. TIA for any advice.
Also, the manufacturer uses similar tx in his new model, the "PRO" and he advised me on the antenna design.

Hi Black Cloud,

this is one of possible solution of problem discussed in this topic:

http://www.geotech1.com/forums/showpost.php?p=119121&postcount=6