lrl

[Fred]

he's just a provocateur

Mmmmh...Not "just" ... a demagogue maybe ?

[J_Player]

Hi,
yes... it's as you described, I asked Esteban many times about his LRL things... and never got a complete schematic to test nor accurate description of e.g. signal and receiver even theoretical and not plain schematics but the usual, almost always boring, vague description or some old picture of scientific amateur books... or moder mechanics stuff etc.

the unsaid about Esteban's LRLs and thus Alonso's one too is that they always thought that a critical tuned receiver design is the lead to LRL to work...

you can see that reading between the lines of such posts , where e.g. Esteban show pictures of an old quartz crystal nobody use today, or when talk about ferrite critically tuned MDs etc.

In the case of tape head amplifier I remember he's strategy was to build an antenna (something VHF stile, using aluminium) then put a ferrite toroidal core with coil in the antenna frame and then connecting the whole thing to the tape head amplifier and beep generator.

The basic idea of this approach is having a HUGE electrical separation (thus impedance) between the sensing coil and the antenna... and the reason is obvious to me: his antenna stuff is critically tuned ! so any change in impedance or load will disturb the critical tuning... read reasonance of the LC component in the antenna circuit

BUT BUT BUT

the question is: what the hell he's trying to detect in the VHF range from a buried target ??? and what's frequency he's looking for ???

never told us... but I guess it's a beacon in VHF , probably just up the end of broadcast band for FM (>110MHz) and looking for an AM signal, an e.g. VOR, NavAid and ILS for airplanes (http://en.wikipedia.org/wiki/VHF_omnidirectional_range)

BUT BUT BUT

we know that VHF is not suitable (usually) to detect underground stuff (unless we talk of e.g. low-res GPR)... so seems pure non-sense from him...

I strongly think that these guys are very passionate RF amateurs and built thousands of coils , receivers etc... using transistors and tubes maybe from the 60s! but this cannot explain their claims

the VHF reflection IS possibile but not by stuff underground so I think they are self-decepted or have illusions that the target acts OVER the soil, by their ion clouds or something to show and make RF reflection appears just over where the item is buried....

this could maybe explain why all their electronic LRLs have RF receivers inside that goes from LF to VHF and maybe even higher frequencies



regards
Max

Hi Max,
Before I get into details of the Esteban design, a simple answer to solve mesy64 request for circuit schematic help:
WM6 has already posted a circuit diagram you can use for the preamp:



As I said, this is only one of thousands of preamps you could use, and it looks like a good guess to me.
I doubt it will work, but who knows until you try it?
Now you have all the missing parts to the circuit so you can connect 6v batteries to a 5v regulator and wire the 5 volts to the circuit above and also to the + connection on the tape head amplifier and beeps generator.


About the Esteban circuits....
This particular circuit is not VHF. It is VLF. It seems to me Esteban used three different frequencies: AF which was usually 400 Hz for audio signals, VHF tuned just above the FM broadcast band, and VLF usually at 62 KHz.

The VLF is easy to understand because it penetrates into the ground and can be used to find anomalies when monitoring the RX in a survey mode. The choice of 62 KHz would seem to be a compromise to move the frequency as high as possible for locating smaller things while not losing too much depth penetration into the ground. But what Esteban answered when asked about this is he has used many frequencies between 15 KHz and 180 KHz. He said he found the best results at around 60 KHz because higher and lower frequencies would pick up too much aluminum, or would pick up too much stray noise.

The combination of VHF and AF is seemingly a different principle of operation. The only comprehensible theory I have read published here is that buried metals cause anomalies in the wave propagation near the surface at the VLF frequencies. By doing some weird mixing of audio and RF signals, Esteban said he could hear a "difference" in a 400 Hz audio sound he was tuning from a 110 MHz modified pocket radio. This "difference" in the sound may be referring to a tone change, or pitch change, or waveform change at the same pitch. This translates to phase shift, 400 Hz frequency shift, 400 Hz audio wave deformation, amplitude change, or possibly other things that changed in the circuit.
We don't know anything about it because we do not have the circuit to test and find out.
All we know is that he reported a change in the 400 Hz sound he heard on the modified FM radio.

Also to note about the 400 Hz sound he tuned... He did not use a transmitter to send the frequency of the pocket radio (110 MHz). This radio was picking up noise from his 400 Hz switching circuit nearby. This makes me think of broadband noise at the rise and fall of the 555 timer that makes a square wave for the 400 Hz. But we see this square wave is driving a LED and also runs through a few turns of a loop. A very strange circuit indeed. We can see he took care to tune to a dead spot on the band so there would be no broadcast interfering with 400 Hz the noise he picked up. This tells me this circuit does not depend on a VHF broadcast. He only used the receiver to pick up local noise from his audio oscillator and attached wiring. If I were to speculate, I would look at the broadband noise made by the audio circuit and examine it on a scope with an air probe to see how the noise changes when you point toward a buried object.

...Would you be, by any chance, a teacher, or an anarchist ?

Hi Fred,
In the past, I had a job where part of my work was to teach technical things to workers who would be operating machines that our company manufactured.
I don't like the idea of anarchy. I think it is good to have a governing structure.

Best wishes,
J_P

[Max]

Hi J_P
ok but the 400Hz he said could be explained in other ways still considering the option of the external (far) transmitter both LF range (62Khz) and also maybe in VHF (>110Mhz)

400Hz is a freq. tone used in some old BFO detectors

now suppose the theory of Esteban (or Alonso) is that they untune a little their local oscillator to get some freq. 400 above or less than the supposed external "carrier", means that if the carrier from beacon or time station is e.g. 62000 Hz they tune to 62400 Hz (a clear frequency with not much interference in LF band) then they put the directive antenna with ferrite in null position respect to the max receive edge (that's 90° offset)... I remember that many times he pointed that walking in straight lines using directional indications (e.g. north-south or the like), they will have a null signal or minimum they could balance electronically to reject

then now suppose the metallic mass of target buried could reflect incoming rf waves: there could be a local anomaly in waves propagation , an increase in signal entering receiver and thus mixing the received signal with local oscillator signal they could get the difference , so 400Hz

Now... all this supposed working ( ) if the transmitter has a VERY stable frequency (and e.g. time signals tx HAVE, like the one of NIST) , the local osc. has a VERY stable frequency (in the tens of ppm or less) they could really get exactly e.g. 400.00001Hz and not 401 or 400.1Hz from signals mixing and thus get a clear indication that the signal received is not from noise if too weak , I mean if they use BFO approach with very accurate frequencies on local and remote source they actually improve much S/N ratio on detection of small and weak signal above the background noise , maybe they use cascaded or active filters to catch that 400Hz and ignore all the rest

the fact he was talking of ppm variation of frequencies, stabilized by quartz crystals also let me think one criticality is frequency stability for BFO operations and I actually think that his real preamp uses an ultrastable local oscillator with integrated mixer (a transistor I think), then put the output mixed signal in input to the tape head amplifier: the tape head amplifiers have incredibly good S/N, 400Hz is within the working range, and they do not introduce much distortion in signal (so e.g. much frequency shifts) , then maybe the 400Hz signal drives the 555 some how to get some monostable interval e.g. 100mS to give the user a more solid detection , maybe cause reception of reflected waves could be tricky to detect e.g. walking and is too rapid to trigger consistent audio indication.

Just theory , of course, remainding what he wrote here... but I think his PDs are based all on these ideas...

but I don't think that stuff work

regards
Max

[mesy64]

HI
I want to make a receiver circuit waves in metals such as coins would be below the soil surface
When you search the forum I saw a number of circuit designs in this regard, but Esteban was interesting.
I read your posts so I advise every one to But my friends do Ntvantstm result of discussions
You have friends who can help me build a device similar to the Esteban And introduced me to a schematic with respect

[mosha]

HI
I want to make a receiver circuit waves in metals such as coins would be below the soil surface
When you search the forum I saw a number of circuit designs in this regard, but Esteban was interesting.
I read your posts so I advise every one to But my friends do Ntvantstm result of discussions
You have friends who can help me build a device similar to the Esteban And introduced me to a schematic with respect

As JP explain very clear in his previos presentation, no body can help to build Esteban LRL, because Esteban did not show any clear schematic for LRL, but may be Morgan and Geo can help you in the closed RS if the administrator allow you to participate there.

Regards,
Mosha

[Fred]

Hi J_P

Hi Fred,
In the past, I had a job where part of my work was to teach technical things to workers who would be operating machines that our company manufactured.
I don't like the idea of anarchy. I think it is good to have a governing structure.
Best wishes,
J_P

Great answer

[J_Player]

Hi J_P
ok but the 400Hz he said could be explained in other ways still considering the option of the external (far) transmitter both LF range (62Khz) and also maybe in VHF (>110Mhz)

400Hz is a freq. tone used in some old BFO detectors

now suppose the theory of Esteban (or Alonso) is that they untune a little their local oscillator to get some freq. 400 above or less than the supposed external "carrier", means that if the carrier from beacon or time station is e.g. 62000 Hz they tune to 62400 Hz (a clear frequency with not much interference in LF band) then they put the directive antenna with ferrite in null position respect to the max receive edge (that's 90° offset)... I remember that many times he pointed that walking in straight lines using directional indications (e.g. north-south or the like), they will have a null signal or minimum they could balance electronically to reject

then now suppose the metallic mass of target buried could reflect incoming rf waves: there could be a local anomaly in waves propagation , an increase in signal entering receiver and thus mixing the received signal with local oscillator signal they could get the difference , so 400Hz

Now... all this supposed working ( ) if the transmitter has a VERY stable frequency (and e.g. time signals tx HAVE, like the one of NIST) , the local osc. has a VERY stable frequency (in the tens of ppm or less) they could really get exactly e.g. 400.00001Hz and not 401 or 400.1Hz from signals mixing and thus get a clear indication that the signal received is not from noise if too weak , I mean if they use BFO approach with very accurate frequencies on local and remote source they actually improve much S/N ratio on detection of small and weak signal above the background noise , maybe they use cascaded or active filters to catch that 400Hz and ignore all the rest

the fact he was talking of ppm variation of frequencies, stabilized by quartz crystals also let me think one criticality is frequency stability for BFO operations and I actually think that his real preamp uses an ultrastable local oscillator with integrated mixer (a transistor I think), then put the output mixed signal in input to the tape head amplifier: the tape head amplifiers have incredibly good S/N, 400Hz is within the working range, and they do not introduce much distortion in signal (so e.g. much frequency shifts) , then maybe the 400Hz signal drives the 555 some how to get some monostable interval e.g. 100mS to give the user a more solid detection , maybe cause reception of reflected waves could be tricky to detect e.g. walking and is too rapid to trigger consistent audio indication.

Just theory , of course, remainding what he wrote here... but I think his PDs are based all on these ideas...

but I don't think that stuff work

regards
Max

Hi Max,
I don't think the VLF beacon transmitters have anything to do with the VLF receivers that Esteban built.
I think his receivers were adjusted to work at dead spots where he would receive no broadcasts except what he sent out from his oscillators.

The exotic circuits we read about with crystals and and mixers appear to be attempts to process a signal so he could easily hear an audio tone as a result of a very slight change to a high frequency. I do not believe these precision frequencies had anything to do with broadcasts from distant transmitters or a "treasure signal". My opinion is there is no specific frequency dedicated to gold or other metals. Just as there is no specific frequency dedicated to detecting music. We can detect music an many different radio frequencies by using many decoding schemes. The final music we hear is all the same, even though we can tune it from KHz, MHz or GHz, and a lot of other bands in between those. I think the same for detecting metals. What is the gold frequency we must use for a metal detector? Can be 5000 Hz, 7000 Hz, 50 KHz, or less than 400 Hz for some PI detectors. frequency not so important because there is no gold frequency. Frequency is only important to choose a frequency that will work ok for your detection method. I think same for LRL, but only for an LRL that will actually work when tested. I think not for MFD where people believe the gold is vibrating at a frequency they can detect. Same as it is not vibrating at a frequency that a metal detector can detect.
So for my discussion, I do not talk about gold detection frequency. I see only frequencies that were chosen for convenience... ie: 110 MHz is convenient because easy to use FM receiver. 400 Hz is convenient because easy to hear and build with 555 timer.

What I think about the Esteban circuits is he had only two basic detecting methods. The VLF which works based on RF absorbance/reflection of VLF from his transmitter, and the AF which is not related to the VLF or other FM band frequencies.

For the moment, lets take another look at the 400 Hz signal. Actually I don't think there are any VHF dynamics at work in the 400 Hz detector. The 110 MHz receiver frequency I think he chose because it was easy to tune a old style FM radio to a dead spot by bending one of the coils to raise the frequency slightly out of the broadcast range. I think he would find the same results at a dead spot near 50 MHz or 200 MHz. From What I see in his posts it appears he was only picking up noise that is radiated from his nearby audio circuit. Certainly there are no transmitters sending a signal at the frequency he tuned the receiver to.

So let's look at the 400 Hz circuit from an engineering point of view rather than Esteban's theory point of view. We have a 555 timer sending a square wave through 2 LEDs and a few turns in a loop. I know from my own recent measuring 3v calculator switching circuits in the audio range I could detect the switching up to 6 inches distance from the calculator in best conditions. I particularly noticed the rise and fall times which had much higher frequency noise during the settling from high and to low states. what I found surprising is the dc components were preserved when I recorded these square waves at some distance through the air. The wave shape could be distorted by using a coil pickup or capacitors of certain values, and combinations of them. But the Esteban circuit is not a simple square wave like a calculator. This square wave signal is sent through a loop which allows any radiated signal to travel farther than the 6 inches I could measure from a calculator running at a lower voltage. I don't expect this loop to have any tuning ability for the audio frequency of the 555, or not even for the broadband noise. But I do expect it to act as a larger surface conductor to spread whatever signal is radiating from the switching. How do I know this? I don't. It is only my best estimate of what I think is happening after spending a lot of hours observing small audio signals leaking from various calculators and mobile phones.

Since Esteban kept the receiver close to the audio circuit, it was able to detect the noise and make a 400 Hz sound on the speaker. The receiver frequency was unimportant as long as it did not receive a broadcast from some distant transmitter. Any VHF frequency in the range could pick up the audio noise. Then the interesting part. According to Esteban, When he pointed the audio loop toward buried metal he heard something change in the sound. This is not his theory, but what he says he observed. If this change in the sound is true when pointing to buried metal, then it means we could measure a change in the audio signal that radiates into the air from the 400 Hz circuit. This is one of the few Esteban LRLs which we could actually take measurements from to see what the signal really is. We would not need to worry about influencing the internal circuit with test probes because all we need is a small probe in the air to see this signal -- same as the FM receiver sees the signal. If this signal is strong enough to make a noise interference on an FM radio, then it is certainly strong enough to make a signal you can see on a modest cost oscilloscope.

From my point of view, this is how you can find some information to learn about the signal that Esteban measures on his 400 Hz circuit. I believe you can take these measurements even without putting the FM receiver nearby. You only need the 400 Hz circuit and a scope that can pick up the air signals around it. Then move the circuit around to where there are buried things to see what changes you find in the audio.

I should also point out your ear is much more sophisticated for hearing very slight changes in the sound than the image you see on an oscilloscope. We can hear small changes in wave shape and phase that are hard to see on a scope without making overlays of signals before and after. But for bigger changes in the sound, they can be easy to spot on a scope trace.

Finally about the Esteban/Alonso theory...
I remember often Esteban talking about his theories, which were sometimes obviously wrong, and other times probably correct. One thing I learned is that you can count on he would report what he observed. But often he would also report things that were not observations, but his conclusions. By this I mean he once talked about the phase change in the 400 Hz. When I asked him how he knows there is a phase change, he explained he only assumes... it turns out that what he heard some kind of change in the sound which he did not describe exactly to be a change in frequency, pitch, or tone or loudness. He only said the sound changed. So I see he did not observe any phase change, but a change in the sound he heard. And I am careful to look for places where he is reporting observations like a change in the sound, rather than conclusions such as the audio signal phase shifted. These seem like small details, but they are extremely important if you want to understand how the signal is detected. Instead of assuming, you can connect instruments and look to see exactly what the signal is. No need to guess. For people who insist it is ok to assume, then they can spend years looking in the wrong place for answers that can easily be seen by checking to be sure instead of guessing.

Because Esteban has often mixed his conclusions with his observations, I suspect that he is not certain of the theories he has about what is causing this change in the sound, and probably does not know what physical events cause the change other than "the phenomenon". The problem is nobody ever defined exactly what is "the phenomenon". It seems to have different properties for each person who says they observe it. Most metal detectorists who describe it say it simply causes long-time buried metal things to have a very strong detector signal until after they dig it up. Then signal returns to normal. But LRL hobbyists describe many different properties which are not the same from one person to another. Other people who have not observed any "phenomenon" describe it as something that does not exist.

As for the 400 Hz signal, I actually don't know what is being detected with the 400 Hz locator. I would not try to guess because there is an easier way to find out. You only need to build one and test it on instruments to see what is changing. It seems a pretty easy project.


Best wishes,
J_P

[WM6]

The 110 MHz receiver frequency I think he chose because it was easy to tune a old style FM radio to a dead spot by bending one of the coils to raise the frequency slightly out of the broadcast range. I think he would find the same results at a dead spot near 50 MHz or 200 MHz.

Yes, frequency of receiver is not important, it only need to be FM. To use commercially available 110 MHz receivers is only more comfortable than build something new.

[Max]

Hi,
I don't think it's FM at all, cause if you remember Esteban's "design" with the toroid and antenna frame+ tape head amplifier it's fully AM thing... cause tape head recorders do not modulate by freq the signal so it's just matter of AM detection and modulation I think, and that's also this way in the case of VHF range, cause over 100MHz the navaid and aircraft band uses narroband am transmission over the VHF carrier

also if we consider the 62KHz range there's no room for real FM in that bands and modulation is always AM kind, like happens with time signals

but maybe I'm wrong, Esteban knows...

Kind regards
Max

[WM6]

There are different Estebans design. One, which use FM receiver, is based on signal propagation phase "anomalies" supported by adequate circuit, which can be detected only by FM receiver. Tape recorder design is other things. First is based on some sort of signal frequency modulation and other one on changing in amplitude (all depending on antenna(s) direction).

[mesy64]

Dear friends, wm6,max,j-p,mosha and....
I was confused account of the discussions you
Please give me a schematic of this type of detector?
In general, a circular coil connected to an input amplifier Perry is causing the waves emitted by metal buried beneath the soil to reveal???:

[Aziz]

Hi guys,

go and read the antenna basics before making any speculations and assumptions.

And consider the following fact:

A similar comparison to the astronomy:
Your detector is detecting only to micro wave and infra red spectrum. But you want to detect small particles. The emission (TX) isn't absorbed by the small particles, they "ride" with the EM waves. The small particles aren't visible to your detector.

Transfer this to the frequency spectrum VLF.
All the small targets can't be detected really. They don't either absorb nor reflect the TX emissions. They are completely invisible to the very long EM waves.

To understand it better, look at the reflector part of directional antenna basics.
When does a reflector reflects EM waves?

Radios & LRL's aren't metal detectors!
All this LRL stuff is bull$hit. It is what it is: bull$hit.
Enough bull$hit guys.

Aziz

[WM6]

Please give me a schematic of this type of detector?

:

You ask for schematic of casette recorder you use too?

[WM6]

Transfer this to the frequency spectrum VLF.
All the small targets can't be detected really.

This is true Aziz, but who is asking for small targets? Mesy has here of tons of gold in mind.

[Aziz]

This is true Aziz, but who is asking for small targets? Mesy has here of tons of gold in mind.

Look at the wave length of a 30 kHz or 100 kHz EM wave and compare it with a gold coin or gold ring dimension.

Wave length wl = c/f [m],
c = speed of light [m/s]
f = frequency of EM wave [1/s]

Put f=100 kHz and let's see, what wave length wl is:
wl = (300 000 000 m/s) / (100 000 /s) = 3000 m.

Oh $hit, our gold ring is a small particle now!!!!
Oh $hit!

Aziz