Basic MFD Project

by Carl Moreland

Introduction

Molecular Frequency Discriminator (MFD) has become a popular term to describe electronically-enhanced dowsing rods. There are two components to the typical MFD: a signal transmitter, and "receiver" L-rods. Construction of the L-rods is covered in the Building LRLs report and will not be repeated here. We will focus on the signal generator.

The prevailing theory behind MFDs is that the signal generator transmits at a frequency that matches the "molecular resonant frequency" of a desired target. The most common frequencies used are 5KHz for gold and 8.7KHz for silver; other elements have different frequencies but we will focus only on gold and silver. Therefore we need a signal generator that can switch between two different frequencies.

There are many ways of generating signals, with tradeoffs in circuit complexity, accuracy, stability, and flexibility. Accuracy refers to the ability to tune to an exact frequency; stability describes how well the generator can maintain a certain frequency over time and with temperature variations; and flexibity means how easy it is to change the frequency or amplitude.

The simplest is probably a ring oscillator, the most complicated might be a crystal-controlled Direct Digital Synthesis (DDS) chip. The ring oscillator, while incredibly simple, has poor accuracy, poor stability, and moderate flexibility. DDS offers the precision and stability of a crystal oscillator while adding the flexibility of millihertz tuning. In between are a wide variety of methods, including a couple of fairly simple yet flexible function generator chips.

MFD1: Basic MFD

One such chip is known as the "8038" (originally made by Intersil, and now produced by several companies) and provides a reasonably clean sinusoidal output as well as triangle and square waves. The output frequency is set by a few external components so it is easy to use, and it is inexpensive. Another similar chip is the Exar XR2206, which has a little better stability and cleaner waveform than the 8038, but is harder to find. We will use the 8038.

Fig. 1: Transmitter Schematic

Figure 1 shows the 8038 signal generator circuit. This is a very standard configuration given in the Intersil data sheet. The output frequency is set by R1 and C1 (plus C2) to be approximately f=0.15/(R1*C1). The sine wave output at pin 2 is then fed through an R-C low-pass filter (R4-C3) to the LM386 audio amplifier. Figure 2 shows the PC board for this circuit. Note that the PC board includes some extra pads for optional circuitry that is not used in this project.

Fig. 2: Transmitter PC BoardClick on image for 300dpi resolution (scanned at 2x)

Since this MFD is only designed for gold and silver there are only two frequency selections and therefore the 8038 only needs two capacitors. One capacitor (C1) is always connected to the 8038 and results in a frequency of 8.7KHz. S2 switches in a second parallel capacitor (C2) that decreases the frequency to 5KHz. The low-pass filter (R4-C3) has a cut-off frequency of around 10KHz and helps suppress the output harmonics of the 8038 for better spectral purity. Finally, the LM386 provides gain and drive capability for the ground probes.

The only drawback to using an 8038 is that it requires more than 9v to operate, therefore it cannot be run from a single 9v battery. An 8-pack of AA's will produce 12v which is barely sufficient; 2 series 9v batteries is the best solution. You should put the circuit board in an appropriate enclosure: my solution is shown in Figure 3, with the batteries inside the case. The enclosure has a power switch, a frequency select switch, a battery test switch and LED, amplitude knob, and two banana jacks for signal outputs.

Fig. 3: Final TX Package

The amplitude adjust potentiometer R5 allows the user to vary the output signal level which determines the maximum distance the MFD will detect a target. You can eliminate the pot and make R5 a fixed 50K resistor for a fixed full-power output. As shown, the battery check circuit is designed for 18v operation and will cease working when the battery voltage drops to about 13v. You can eliminate the battery check portion of the MFD if desired.

Once we have the circuitry working what do we do with it? We will do what every other MFD manufacturer does: connect the output leads to probes that are stuck in the ground. Each probe consists of: a short (6") piece of 2" PVC pipe, two 2" end caps, a 12" length of 3/16" brass rod, a banana jack, a wire clamp, and some wire. Figure 4 shows the material needed to make two probes.

Fig. 4: Probe Parts

First, use a high-quality drill bit and drill a 3/16" hole through the center of one of the end caps and just slightly into (but not through) the inside roof of the other end cap (see Figure 5). The brass rod should slide through the hole with a considerably tight fit which is why you want to use a high-quality drill bit. Cheap bits tend to have inaccurate sizes. Drill a hole in the side of the 6" long pipe to accept the banana jack and solder the wire to the jack. Assemble everything but the top end cap. You may want to clean and paint the short pipe section for a sharp appearance.

Fig. 5: Upper cap Fig. 6: Assembly

Fig. 7: Final Probes

With the rod pushed through the assembly by a couple of inches use the clamp to attach the wire to the rod (Figure 6). Finally, add the top end cap making sure the rod goes into the half-hole in the inside roof, then push everything together. You may want to add PVC cement to the end caps and some epoxy where the brass rod goes into or through the end caps to hold everthing together securely. Sharpen the tips of the probe rods (to about 45-60 degrees) to make it easier to push them into the ground.

In Figure 6 you may have noticed that the connecting wire from the banana jack to the rod is spiraled around the rod. This technique generates a molecular polarization field that is directly induced into the probe rod and eliminates all false (ghost) signals. The spirals should be wound in opposite directions for each probe. Once the probes are finished you will need to make a pair of banana wires to connect the MFD transmitter to the probes. The finished probes are shown in Figure 7.

This concludes the instructions for the MFD transmitter. Together with the L-rods described in Building LRLsthe total package is shown in Figure 9. The materials cost of this package should be around $50: $15 for the L-rods and $35 for the transmitter. It is exactly equivalent to MFDs being sold for up to $2000.

Fig. 8: Total MFD Package

At this point you should be ready to try out the MFD. Insert the two probes into the ground about 2-3 feet apart. Using banana wires connect the probes to the MFD transmitter. Turn on the transmitter and grab the L-rods. Walk a circle (about 10-12 feet out) around the probes until the L-rods cross - you have located a potential signal line. Mark this point. Imagine a line connecting the marked spot and the middle of the probe area. Move farther away (say, 30 feet) along this line and, using the L-rods, try to locate the signal line. Continue moving away from the probes as long as you are able to detect the signal line. Make sure you mark all of your signal hits.

Fig. 9: MFD Techniques

At some point as you move farther away from the probes you will cease detecting the signal line. If you detect a signal line out to a certain distance from the probes but the signal seems to stop, then where it stops shouldbe the location of the target. Before you dig, you can verify this by moving the probes 90 degrees around the target point and triangulating. The target will be at the location where the signal lines cross.

Fig. 10: MFD Triangulation

There are two potential pitfalls with MFDs and both are due to the incredible sensitivity. An MFD has the ability to pick up target signals from as much as 10 miles away, though 1-3 miles is more typical. This means that it can take quite some time and effort to trace out the signal line. Once you have the target pinpointed you may have to face another problem: depth. The MFD can detect targets as deep as 100-200 feet, so locating the target is only half the battle. If a metal detector does not verify the existance of a metal target at

the identified location then you should bring in excavation equipment. If no obvious target is found when you reach 200 feet, then the target was most likely subatomic gold particles - you cannot see it and most chemical analyses will not detect it either, but the MFD will.

Usually there is no oscillator connected to the rods. But if you want to connect an oscillator for a frequency of 5 kHz and 8.7 kHz, then you can make the electrical connections with the method you see below. The + and - wires that are normally connected to the ground probes can be connected as shown.

Best wishes,   J_P

  #36  

 02-09-2012, 05:35 PM

J_Player Guru

 Join Date: Feb 2006Location: CaliforniaPosts: 4,351

Quote:

Originally Posted by michael Hi J_Pyes, that's right.it has no output range, just 6 preset output frequency + those 7 funny user-set options.I don't remember exactly LRL2000D wave voltage. just know Notsi LRL2000D amp is TDA7294. I think have put the info somewhere in this forum.After that my friend made one radio frequency generator with very vast frequency range (from 1Hz to 500KHz) I remember its' amp was STK435. my test result for this one was the same as Notsi LRL.

I am guessing the frequency meter you used is a portable battery operated frequency counter that has an aerial antenna and two test probes with alligator clips, that do not have a shield. From what you say, you got no signal except when you tried at a way you call ground mode. yes, that's right.

I have difficulty to understand how you connected the two alligator clip leads.From what I read it sounds like you dropped both alligator clip wires into a vase that you buried in the ground.No, As I wrote, I planted two iron rod in ground and plugged each alligator to each one.

But I believe you made some detection at the distance you say.Yes, it could be detectable in all directions/paths

Maybe if we learn the voltage and frequency at the MFD probes and the distance they were set apart, and exactly where each of the two frequency counter probes were connected to, we would have some idea how to make a similar test. I checked for each frequency, all were detectable up to 2 meters.MFD probes distance was ordinary; 30-40 Cm. had no difference in result.FR-counter probes distance also were close; 20, 30 or 40 Cm.

One question: Did your Bulgarian locator work to locate any treasures? No, never and ever. 

Best Wishes.

Hi Michael, Now it begins to make sense that you measured a signal in the ground much farther than I did. The TDA7294 in your Bulgarian locator is a 100 Watt amplifier running at 24 volts. Interestingly enough, this is an audio amplifier intended for high power home stereo sound systems. And the specs are quite good for an integrated amplifier. When putting out 50 watts of power, the maximum harmonic distortion is 0.1% over a range from 20Hz to 20 KHz. This means if you put a very clean sine wave into this IC, it will deliver a very clean sine wave out, except at a much higher power level. The best part is you don't need to build huge circuit board full of transistors to attain this power. It is all contained inside the single IC. You simply add a few resistors and capacitors around the TDA7294.But if you connect the TDA7294 in a way that allows it to put out a full 100 watts of power, then you will need a good size heat sink to dissipate the heat that comes from the IC. 

I don't know how the power was transferred from the TDA7294 to the ground in your in your

  #37  

 02-10-2012, 07:44 AM

Dedevil Banned

 Join Date: Oct 2011Location: HellPosts: 262

 holding his own hand

I believe he is just holding his own hand and trying to lead us all down his golden path.

It's an audio amplifier and nothing to do with l rods unless you connect the output to a speaker and give the ground a sonic blast.Don't Laugh! This system is actually used for offshore geophysical detection. But the blasts are much louder.rgds

Last edited by Dedevil; 02-10-2012 at 07:50 AM. Reason: after thought

  #38  

 02-10-2012, 09:00 AM

J_Player Guru

 Join Date: Feb 2006Location: CaliforniaPosts: 4,351

It turns out this TDA7294 amplifier is even more interesting than I thought. Aside from being a very low distortion high power amplifier, it runs on a dual power supply that the signal generator IC can share with it. This means you can use the two 12v batteries like Michael has in his Bulgarian LRL to run both the TDA7294 power amp and the signal generator. The output from this amp will be higher because of it's 24 volt supply instead of the 12v that the signal generator is using above. But this is not a problem, the 8038 signal generator is good for up to 30 volts each side of the supply. So we can plug it into the same supply and send the signal to the TDA7294 all on the same board if we want. This seems quite convenient for MFD builders. 

This amplifier is intended to drive typical speakers from 4-8 ohms. Since the ground usually has much higher impedance, We cannot expect to put the full 100 watts of power into the ground. But since it can handle up to 100 watts, it seems a good candidate for a step-up transformer to increase the voltage at the probes to get more power into the ground. Of course, power transistors could do this too. The main difference is this IC is able to maintain a very clean signal without distorting it at power levels, and it is on a single IC. When we start sending more power out, we can expect the amplifier to heat up, so we need a heat sink that will carry the heat away. The image below shows a typical heat sink used on an audio amplifier. But this could be made smaller, especially if you include a fan to circulate air through the fins, similar to how computer fans work. 

Because this IC matches up so well to the 8038 signal generator, I show some concepts of how you could hook it up below. This is not a circuit I tested, but I think it may work if I didn't get any mistakes in the connections. 

In the circuit you can see I changed the two capacitors that set the frequency for the 8038 to a bank of 6 capacitors with a rotary switch to select which frequency you want.You can fill in any capacitor values for your favorite frequencies. There is also an option to make adjustments to the frequency at pin 4 on the 8038, or you can leave it in the original design. You can also see where the transformer goes. You can choose the transformer type depending on the soil conditions. I think you will have a wide range of soil impedance depending on ground mineralization and how wet the soil is. For this reason, I doubt any one transformer would be suitable for all soil. But at least you have some control at the power knob. Another option would be an adjustable auto-transformer that you can change to suit the soil. But don't forget the batteries. When you put out more power, you need bigger batteries. 

Keep in mind that Michael's Bulgarian MFD locator uses this same amplifier, but he was able to detect nothing ever, even though he could measure the signal in the ground up to 2 meters distance.And that is exactly what I think you will detect with this MFD detector... Nothing. If you think I am wrong and this circuit really can locate treasure, prove me wrong. 

  #39  

 02-11-2012, 12:54 PM

Dedevil Banned

 Join Date: Oct 2011Location: HellPosts: 262

 Have you thought of?

Quote:

Originally Posted by J_Player It turns out this TDA7294 amplifier is even more interesting than I thought. Aside from being a very low distortion high power amplifier, it runs on a dual power supply that the signal generator IC can share with it. This means you can use the two 12v batteries like Michael has in his Bulgarian LRL to run both the TDA7294 power amp and the signal generator. The output from this amp will be higher because of it's 24 volt supply instead of the 12v that the signal generator is using above. But this is not a problem, the 8038 signal generator is good for up to 30 volts each side of the supply. So we can plug it into the same supply and send the signal to the TDA7294 all on the same board if we want. This seems quite convenient for MFD builders. 

This amplifier is intended to drive typical speakers from 4-8 ohms. Since the ground usually has much higher impedance, We cannot expect to put the full 100 watts of power into the ground. But since it can handle up to 100 watts, it seems a good candidate for a step-up transformer to increase the voltage at the probes to get more power into the ground. Of course, power transistors could do this too. The main difference is this IC is able to maintain a very clean signal without distorting it at power levels, and it is on a single IC. When we start sending more power out, we can expect the amplifier to heat up, so we need a heat sink that will carry the heat away. The image below shows a typical heat sink used on an audio amplifier. But this could be made smaller, especially if you include a fan to circulate air through the fins, similar to how computer fans work. 

Because this IC matches up so well to the 8038 signal generator, I show some concepts of how you could hook it up below. This is not a circuit I tested, but I think it may work if I didn't get any mistakes in the connections. 

In the circuit you can see I changed the two capacitors that set the frequency for the 8038 to a bank of 6 capacitors with a rotary switch to select which frequency you want.You can fill in any capacitor values for your favorite frequencies. There is also an option to make adjustments to the frequency at pin 4 on the 8038, or you can leave it in the original design. You can also see where the transformer goes. You can choose the transformer type depending on the soil conditions. I think you will have a wide range of soil impedance depending on ground mineralization and how wet the soil is. For this reason, I doubt any one transformer would be suitable for all soil. But at least you have some control at the power knob. Another option would be an adjustable auto-transformer that you can change to suit the soil. But don't forget the batteries. When you put out more power, you need bigger batteries. 

Keep in mind that Michael's Bulgarian MFD locator uses this same amplifier, but he was able to detect nothing ever, even though he could measure the signal in the ground up to 2 meters distance.And that is exactly what I think you will detect with this MFD detector... Nothing. If you think I am wrong and this circuit really can locate treasure, prove me wrong. 

Best wishes,    J_P

Get off that space flight from NASNA and back to reallity?

  #40  

 02-11-2012, 05:50 PM

J_Player Guru

 Join Date: Feb 2006Location: CaliforniaPosts: 4,351

Quote:

Originally Posted by Dedevil Get off that space flight from NASNA and back to reallity?

We are searching for an LRL THAT WORKS

Do you have an MFD schematic that works? Post the schematic here. 

Best wishes,   J_P

  #41  

 02-11-2012, 06:23 PM

Geo Guru

 Join Date: Mar 2005Location: GreecePosts: 2,835

Quote:

Originally Posted by J_Player Do you have an MFD schematic that works? Post the schematic here. 

Best wishes,   J_P

Most MFD works if the user knows how to keep the rods. Do not you wait from first time to keep

the Lrods and to go directly to the buried objects  . As all the things.. it need hard work

Regards__________________Geo

  #42  

 02-11-2012, 07:53 PM

J_Player Guru

 Join Date: Feb 2006Location: CaliforniaPosts: 4,351

Quote:

Originally Posted by Geo Most MFD works if the user knows how to keep the rods. Do not you wait from first time to keep the

Lrods and to go directly to the buried objects  . As all the things.. it need hard work

Regards

Hi Geo,The technique you specify for using MFD was already posted above here: http://www.longrangelocators.com/for...1&postcount=10 

This thread is where ma330 asked for an mfd project and a schematic that works. Do you have a project and schematic to post here that can help him?Quote:

Originally Posted by ma330I need information about a mfd project.And I need a schematic for mfd.Can anyone help me?

Best wishes,   J_P

  #43  

 02-11-2012, 08:38 PM

Geo Guru

 Join Date: Mar 2005Location: GreecePosts: 2,835

Quote:

Originally Posted by J_Player Hi Geo,The technique you specify for using MFD was already posted above here: http://www.longrangelocators.com/for...1&postcount=10 

This thread is where ma330 asked for an mfd project and a schematic that works. Do you have a project and schematic to post here that can help him? 

Best wishes,   J_P

Hi J_P.It is not so simple!!!. Don't think that if you will keep 2 Lrods at your hand then you will find any buried. It needs many experiment.As for schematic... i attached one LRL with generator and it works.

Regards__________________Geo

  #44  

 02-11-2012, 08:50 PM

J_Player Guru

 Join Date: Feb 2006Location: CaliforniaPosts: 4,351

Quote:

Originally Posted by Geo Hi J_P.It is not so simple!!!. Don't think that if you will keep 2 Lrods at your hand then you will find any buried. It needs many experiment.As for schematic... i attached one LRL with generator and it works.

Regards

Hi Geo,This is excellent information. Can you post a list of the experiments that are necessary to find buried treasure for ma330? When he finishes performing the experiments that you show, then he will find treasure the same as you find treasure. 

Also, I do not see your attachment for LRL with generator schematic that works. Can you post that too? 

Best wishes,   J_P

  #45  

 02-12-2012, 10:21 AM

Dedevil Banned

 Join Date: Oct 2011Location: HellPosts: 262

 Thanks Geo

Excellent ciruit diagram of your LRL. Is this your own design? Which program did you use to draw the diagram?

rgds

  #46  

 02-12-2012, 10:45 AM

ma330 Senior Member

 Join Date: Mar 2006Posts: 112

hi jpYou can design for my post number 38 with IC xr2206 Instead of 8038?with respect

  #47  

 02-12-2012, 11:43 AM

Dedevil Banned

 Join Date: Oct 2011Location: HellPost

Quote:

Originally Posted by Dedevil Excellent ciruit diagram of your LRL. Is this your own design? Which program did you use to draw the diagram?

rgds

Just a question? In your schematic after the Ls888tx1 what is the purpose of the output of the R/C circuit.

rgds

  #48  

 02-12-2012, 12:30 PM

ma330 Senior Member

 Join Date: Mar 2006Posts: 112

Quote:

Originally Posted by Geo Hi J_P.It is not so simple!!!. Don't think that if you will keep 2 Lrods at your hand then you will find any buried. It needs many experiment.As for schematic... i attached one LRL with generator and it works.

Regards

HI GEOI can not see your files.Please put your files in RAR formatTANK YOU

Hi Geo

I still do not understands from your schematic posted above as you say R/C if for feedback from pin2?Is this voltage or magnetic type?

This is a very different typ

Geo Guru

 Join Date: Mar 2005Location: Gree

Quote:

Originally Posted by Dedevil Just a question? In your schematic after the Ls888tx1 what is the purpose of the output of the R/C circuit.