Instruction Manual
For the
DISCOVERY Magnetometers
By Quantro Sensing. www.quantrosensing.com
P.O. Box 175 Grant FL. 32949
321 412 1160. 2007. Version 7.1
Section 1. Assembling the sensor, and main electronics housing. Page .
Section 2. Filling the sensor with charcoal barbecue lighter fluid. Page .
Section 3. Setting the tuning for your area of search. Page .
Section 4. An explanation of the controls on the magnetometer. Page .
Section 5. Usage and general search tips. Page .
Section 6. Tone earphone option. Page
Section 7. Care and warnings concerning the proper use of this instrument.
NOTE; All Quantro magnetometers use the same electronics board so the information in this manual pertains to all of our mags.
All mags have RS232 and RS485 serial output built into the board. RS232 and RS485 are outputted after each new reading at 9600 baud speed. RS232 if good for short distance of 6 to 10 feet to a computer. RS 485 will transmit gamma date out to 4000 feet and into a computer through a RS485 to RS232 converter. These converters can be purchased from B&B Electronics.
NOTE: THAT THIS MANUAL IS PURPOSEFULLY PRINTED WITH LARGE TYPE PLEASE READ IT A FEW TIMES.
NOTE: Never turn on the Discovery without fluid in the sensor. The coils will overheat and destroy the sensor!
Warranty
Discovery is warranted for a two year time period from date of sale. We will repair or replace at our sole discretion any defects in the product that have not been caused by mistreatment, abuse or accident.
Discovery is a high quality instrument and if cared for properly it will run for many years.
Specifications.
Discovery is a proton type absolute magnetic field readout magnetometer. Each sampling of the earth’s total magnetic field is computed and displayed as a numeric readout in units of gamma’s. The gamma unit of display is the worldwide industry standard.
The proton sensor is Omni directional. Meaning that it senses ferrous metal in a ball type area with the sensor in the middle of the ball equally in all directions. It is noise canceling, has a high output and a very high gradient tolerance on the order of a 500 gamma’s per meter.
Cycle times are user selected at 2 1/2, 5 and 10 seconds per new reading. Size and weight of Discovery: L. 40” max, W. 4” max, H. 4” max, weight in air 16lbs. Power is 12 volts at 2 amp hr minimal. 4 amp fuse.
Section 1. Assembling the sensor, staff and the main electronics unit.
Underwater/Handheld Magnetometer.
To assemble the unit start by finding a clear area that is clean and soft. A good place would be on a carpeted area or on a blanket.
The sensor is connected to the electronics with a 5 foot wire. Be careful not to pull on the wire while filling the sensor. Sensor must first be filled. See section 2.
Black Box Magnetometer.
Hook up sensor wires to the Black Box electronics enclosure. The white wire and black wire are hooked to the sensing coils in the sensor. It does not matter which wire goes to which sensor terminal. The green wire or bare unshielded wire is the ground wire which is the noise shielding braid that is around the sensor wires in the cable. This is hooked to the offset terminal on the box. Note that this ground wire floats at the sensor end meaning that it is not connected to anything in the sensor. It simply shields the two signal wires from the sensor to the box. Most of the time it will not even be needed (not a very electrical noisy area) but it should be used anyway.
The sensor index marks should be up or down to the ground and the sensor should be aligned with either end pointed to the north or south for the simplest use and best signal.
This is a picture of one of the sensors index marks.
Note: only use a nylon, PVC or fiberglass bolt to hold the sensor so as not to spoil the weak magnetic signal at the sensor.
Boat Towed Magnetometer
Please install the weighted fin down and with the index mark up or down. There are two index marks partially drilled opposite each other into the dark gray PVC end fitting that holds the fins. This will help keep the sensor in the correct position. Snug the set screw with a 1/8 inch Allen wrench. Do not over tighten or you will break the fin.
Install the fins so that the weighted fin goes on last to hold the other fin to the fish. In other words the weighted fin holds captive the first fin installed. The set screw is snugged firm against the weighted fin.
There are two green LED lights on the control box. The lower one is right above the charger plug and lights green when the charger is plugged in and charging.
The top green LED is the battery charge indicator light. Please refer to the Discovery Handheld Underwater info for its indication.
Section 2. Filling the sensor with charcoal barbecue lighter fluid.
Background information.
The magnetometer sensor must be emptied of the flammable charcoal lighter fluid if it is shipped by any Common career.
UPS , FedX and the US Postal Service.
This is due to shipping regulations concerning flammable fluids.
The sensor is emptied by removing the fill plug, turning it over and standing it upside down in a bucket for 5 or 10 minutes.
Charcoal lighter fluid used in the sensor is safe. Most people in this country have had experience using it at one time or another. Be safe!
Filling the sensor.
You will need to buy two quarts of charcoal lighter fluid in a plastic container because it has less of a chance of having small pieces of ferrous steel from a metal container in the fluid.
Also never run the mag without fluid in the sensor because heat may melt the thin insulation on the wires which will ruin the sensor.
Remove the fill plug from the fill hole in the end of the sensor. Only use your hand when tightening this plug snug tight only. Note that this plug has an O ring on it.
Make sure that the sensor is clean, dry and free of sand, water or dirt.
You do not want anything to get into the sensor that may contaminate it and spoil the ability of it to produce the strongest possible signal. Once sand or dirt gets into the sensor it is impossible to get it out. Even a tiny amount may spoil the sensor.
Charcoal light fluid should be used but in a pinch rubbing alcohol (isopropyl alcohol) and even diesel could be used.
Carefully clean and replace the plug and hand tighten until the o-ring makes contact, then one half to three quarts turn tighter.
When properly tightened it should feel much looser to your hand than a normal metal screw would.
Section 3. Setting the tuning for your search area.
The tuning must be set to a close value by looking at the gamma chart. FIND YOUR LOCATION AND WRITE DOWN THE GAMMA VALUE.
Open the charge tune plug or if you have the Black Box version turn it over and look at the tuning switch through the 1 inch tuning hole.
Set the tuning for a new search area using the gamma field value from the magnetic map. This will get you close. The mag field is changing constantly. Presently the field is decreasing at a rate of 60 gamma’s a year.
Use the tuning table to find that gamma value and write down the switch settings that are next to it. These are the closed or on settings. If the table said 1,2,3 then only 1,2,3 will have their levers towards the circuit board. The unused switches will be away from the board or open position. Open meaning that the switch is not connecting the wires so the circuit is open. Or open circuit.
Take some readings in a magnetically clear area at the search area to see how close you came with the tuning. If you consistently get the same reading within a gamma or two write the reading down because it is the absolute field value at that spot.
If the gamma field reading is more than 150 gamma’s from the value you used to set the mag then go back to the tune chart and find the correct value and reset the switches to get the best performance.
You should try one setting above and below the chart setting. Use the most stable of the three. Even 1% components can drift.
The turning chart and magnetic map will always be posted at the Quantro Sensing web site so that you can get the info from any library that has the internet.
NOTE FIND YOUR VALVE AND THEN SUBTRACT 2000 GAMMAS FROM THE SHOWN VALUE THEN USE THAT NUMBER IN THE TUNING LOOKUP CHART FOR THIS CHART.
GO TO WWW.GEOMAG.USGS.GOV FOR REAL TIME MAGNETIC READINGS. USE THE F COMPONENT THAT IS TOTAL PROTON FIELD.
This is a view of the mag tuning switch. It is ten switches built into one mini housing. It is called a ten position micro dip switch. Note how the switches are labeled 1 through 10. Also note that switch 1 is left and 10 is closest to the edge of the board nearest to the charging/tuning plug hole.
This is set at 2,6,7,9 which is for 48,000 gammas.
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
28000g 1,2,3,4,5,6,7,9 47250g 2,6,7,8,9,10
28250g 1,2,3,4,5,6,10 47500g 2,6,7,8,10
28500g 1,2,3,4,5,8,9 47750g 2,6,7,8
28750g 1,2,3,4,5 48000g 2,6,7,9
29000g 1,2,3,5,7,8,10 48250g 2,4
29250g 1,2,3,4,8 48500g 2,6,7
29500g 1,2,3,6,8 48750g 2,6,8
29750g 1,2,3,7,8 49000g 2,6,9
30000g 1,2,3,8 49250g 2,6,10
30250g 1,2,4,5,6,8 49500g 2,6
30500g 1,2,4,5,7,8,10 49750g 2,7,9,10
30750g 1,2,4,5,8 50000g 2,7,8
31000g 1,2,5,6,7 50250g 2,8,9,10
31250g 1,2,5,6 50500g 2,8,9
31500g 1,2,5,7,10 50750g 2,7
31750g 1,2,5,10 51000g 2,8
32000g 1,2,6,9 51250g 2,9
32250g 1,2,7,8 51500g 2,10
32500g 1,2,7 51750g 2
32750g 1,2 52000g 2
33000g 1,3,4,5,6,7,8,9,10 52250g 2
33250g 1,3,4,5,6,7,9 52500g 2
33500g 1,3,4,5,6,9,10 52750g 3,4,5,6,7,8,9,10
33750g 1,3,4,5,6 53000g 3,4,5,6,7,8,9
34000g 1,3,4,5,7,8 53250g 3,4,5,6,7,8,10
34250g 1,3,4,5,8 53500g 3,4,5,6,7,9,10
34500g 1,3,4,6,7 53750g 3,4,5,6,7,8
34750g 1,3,4,6,10 54000g 3,4,5,6,7,9
35000g 1,3,4,7,8,10 54250g 3,4,5,6,7,10
35250g 1,3,4,7 54500g 3,4,5,6,7
35500g 1,3,6,7,8 54750g 3,4,5,6,9,10
35750g 1,3,6,7 55000g 3,4,5,6,9,10
36000g 1,3,6,9 55250g 3,4,5,6,8
36250g 1,3,7,8,10 55500g 3,4,5,6,10
36500g 1,3,7,10 55750g 3,4,5,7,8,9,10
36750g 1.3.8 56000g 3,4,5,6
37000g 1,3 56250g 3,4,5,7,8,10
37250g 1,4,5,6,9,10 56500g 3,4,5,7,9,10
37500g 1,4,5,6,10 56750g 3,4,5,7,8
37750g 1,4,5,7,9,10 57000g 3,4,5,7,9
38000g 1,4,5,8,9,10 57250g 3,4,5,7,9
38250g 1,4,5,9,10 57500g 3,4,5,7,10
38500g 1,4,5,10 57750g 3,4,5,8,9
38750g 1,4,6,9,10 58000g 3,4,5,7
39000g 1,4,6,10 58250g 3,4,5,9,10
39250g 1,4,6 58500g 3,4,5,8
39500g 1,4,7,9 58750g 3,4,5,9
39750g 1,6,7,8,9 59000g 3,4,5,10
40000g 1,6,7,8 59250g 3,4,6,7,10
40250g 1,6,8,9 59500g 3,4,5
40500g 1,6,9,10 59750g 3,4,6,8,10
40750g 1,6,10 60000g 3,4,6,7
41000g 1,6 60250g 3,4,6,9,10
41250g 1,7,8 60500g 3,4,6,8
41500g 1,8,9,10 60750g 3,4,6,9
41750g 1,9,10 61000g 3,4,6,10
42000g 1,9 61250g 3,4,7,8,9,10
42250g 1 61500g 3,5,6
42500g 2,3,8 61750g 3,4,6
42750g 2,3,10 62000g 3,4 7,8,10
43000g 2,3 62250g 3,5,7,8,10
43250g 2,4,5,6,9,10 62500g 3,4,7,9,10
43500g 2,4,5,6,9 62750g 3,4,7,9,10
43750g 2,4,5,6 63000g 3,4,7,8
44000g 2,4,5,7,8,10 63250g 3,4,7,9
44250g 2,4,5,7,8 63500g 3,4,7,10
44500g 2,4,5,7,10 63750g 3,4,8,10
44750g 2,4,6,7,8,10 64000g 3,6,7,8,9
45000g 2,4,6,7,8 64250g 3,4,7
45250g 2,4,6,7,10 64500g 3,6,7,8,10
45500g 2,4,6,7 64750g 3,4,9,10
45750g 2,4,6,9,10 65000g 3,4,8
46000g 2,4,6,9 65250g 3,6,7,8
46250g 2,4,6 65500g 3,4,9
46500g 2,4,7,8,9 65750g 3,4,10
46750g 2,4,7,9,10 66000g 3,6,7,10
47000g 2,4,7,9
Section 4. An explanation of the controls on the Discovery Land Magnetometer.
Switches.
The power switch has three positions.
The up position is 5 second sample update rate.
The center position of the switch is 2.5 second sample rate.
The down position is off.
The fastest sample rate should be used if you’re moving fast and you need many readings. But there is a price that you pay in battery usage.
The Back Box needs a 12 volt battery of at least 3 amp hour size minimal. Only use a 3 amp fuse.
With a fully charged 12 volt 3 amp hour battery at 70 degrees temperature the Discovery will run about two hours at the fastest setting.
Discovery Handheld Under/Water magnetometer will run about 4 hours at this medium setting with a fully charged 3 amp hour battery.
We do not recommend using a 12 volt battery smaller then 3 amp hours.
Gel cell batteries are the best because they are sealed with on battery acid to leak.
Flashlight batteries have steel jackets that are magnetic and should not be used. The 8 size D flashlight batteries need to run the mag would produce a large magnetic target.
Gel cell batteries are small and light. You can find them and a charger for them at any Radio Shack store.
A small 12 volt 3 amp hour battery weighs only 3 pounds. A large 12 volt 10 amp gel cell battery weighs around 10 pounds. Fuse required is 3 amp. Red is positive.
Section 5. Usage and general search tips.
You must use check your shoes for a possible steel shank in the arch. We have seen these to be as large as a wide butter knife. Also check for steel belt buckles and key rings.
Make sure the tune/charge plug is tight before getting into the water. NOTE that the mag will not bubble if it is leaking. You must hold the sensor up and with your face under the mag looking into the clear face plate using gravity to see if there is any water drops. Do this at 10 feet and again durning the beginning of your dive.
Generally you walk OR SWIM with the sensor held out in front of you or off to one side.
The sensor must always have the index marks ether in the up or down position for the best signal. If you turn the mag sideways more the 50 degs or so in either direct from up you will loose the signal and a ERROR reading will be displayed. THIS DOES NOT APPLY TO THE DISCOVERY UNDER/WATER HANDHELD MAGNETOMETER BECAUSE IT HAS A TRUE OMNI DIRECTIONAL SENSOR WHICH READS IN ANY POSITION.
Use of a proton magnetometer is nothing like using a metal detector.
With a metal detector you have to swing the coil from side to side while trying to keep it a few inches off the bottom and also trying to run the coil over every square inch of bottom.
With the Discovery you have a truly Omni directional sensor that senses the same in all directions. Up down left right forward and backward and every other direction in between.
You should think of it like the white sensor is in the center of a 50` ball and it can sense all around equally in all directions.
So with the discovery you walk with the mag in front of you and about three feet up from the ground. Having the sensor up off the ground helps to minimize the small target effects of nails and other small ferrous metal trash. The mag is much easier to use and will search areas 100 X faster than a metal detector.
Search Background
It is beyond the scope of this manual to try to fully describe the proper use of a magnetometer.
We strongly urge you to become an expert in the field of magnetic search. There is no other type of remote sensing instrument in the world that comes even close to the ability of a properly used magnetometer to search for a target with 100% results.
If you really did your home work you will be able to search for any size target with 100% confidence of either finding it or knowing for sure that is or is not where you searched.
This can never be said for searches using sonar, all metal type detectors, or pipe finders. At the end of this chapter we will list some recommended reading and other information sources on magnetometer search.
Search
For starting out we recommend that you walk with the Discovery horizontal to the ground and keep the sensor 2 or 3 feet above the ground.
Generally speaking you will find that as you walk in a clean area with no chunks of steel the gamma readout number will not change more than a gamma or two no matter where you go or which direction you walk.
This is now the time to tell you the single most important fact of magnetic search. Please remember this point.
Ferrous steel targets simply distort the natural earth’s magnetic field where they lay. They do not add to or subtract from the field that you are reading. They distort the field by pushing it closer together at one spot creating a higher reading.
Or pull away some of the natural field strength from other spots near the target creating a lower gamma reading at that spot than normal.
So really you are looking for the disturbance in the natural field created by the target when searching for a ferrous object.
An easy way to picture this is to remove the blankets from your bed so that you are looking at a tight bed sheet.
This represents the natural earth’s field without unnatural ferrous steel targets distorting the lines of flux.
Now place a ten pound scuba weight on the sheet (we will pretend that it is ferrous steel) and you will start to picture how targets only distort the natural field value.
Now the sheet is not even all over and some sides of the target make the sheet slope steeper than other sides of the target. So there are some areas around the target where the sheet has less of a slope or change in the field reading than other areas near the target.
Now notice how far from the weight the sheet is affected. This may be one foot, so you could envision that this represents how far away from the target you might sense it or sense the change from the normal field the target made.
If you were to place a heavier target on the bed you would see that the sheet is affected farther away from this larger target. This may be two feet or so away from the weight that the sheet is no longer flat.
This would mean that since the heavier target affected or distorted the field farther out you could assume that you could sense this change from farther away.
Here is a graph that will give you a general idea of how far away you can sense a ferrous target of a given weight.
The chart has two examples already drawn on it. The first is a 1 LB steel target and we want to find out how close we have to pass the sensor to it to get a strong reading of a 5 gamma change from the natural field reading.
We know two of the three variables, one is the weight and the other is the strong reading that we want to see. So we start at the 5 gamma point on the chart and move straight over to the known weight of 1 lb. Now we drop straight down from that point and we have answered the question. Its 6` that the sensor must be within from the target to see a 5 gamma change.
For the second example we will show you another use of this chart.
PINPOINTING
Lets say that we were searching and we ran across a seemingly large buried target. We wondered what it could possible be!
We have some paper along and we noted a 25 gamma increase in the natural field reading when we were about 35` from the center of the target on the east side and the west side.
So when walking east or west through the target area to pinpoint it the gamma reading was 25 gamma higher on both the east and west side of the target at 35 feet away from the center reading over the object.
So looking at the chart we again know two of the three parts to the problem. We draw a line straight over from the 25 gamma value that we noted. Now we look at the bottom of the chart at the feet from the sensor scale and we find our distance of 35 feet and draw a line straight up.
We now see that the target must weight around 2,000 lbs. of ferrous steel to make that kind of a disturbance. There’s something big there. Going one step further you may want to run a coin metal detector over the target to try and determine the outline of the object if it is close enough to the surface.
It is good to practice first in a clean area without targets so that you will build confident in the Discovery’s ability to read the earth’s natural smooth magnetic field.
Next practice on a known target like your car in a field. Keep in mind that a car will be something like a 2000 LB steel ferrous target.
The ferrous weight of the target in pounds is the main determining factor that will set how far away you could possibly sense it. But remember that you’re really sensing the distortion that the metal creates in the normal field.
While walking to and from the target you will see the gamma readout change. It is important to make a mental note of the clean area gamma reading or better yet write it down on a slate. You should only focus on the last 3 numbers of the readout. An example is to remember the 300 in the gamma readout of 45300 gammas.
While walking towards the boat from 150` feet away the readout will stay the same reading after reading until you get to within 75`feet or so.
Then you will see the gamma reading rise a gamma or three from 300 to 303. Still walking closer at 50 feet you will see the gamma reading rise to 330. Walking closer at 30 feet away it will read around 380. Closer at 20 feet away it will read 550.
While walking away you will see the gamma reading dropping back down to the normal no target earth’s field reading that you noted earlier.
So the field may change 500 or more gammas’s if you get close to a large ferrous object.
Locating and pinpointing a target
Locating any ferrous metal target is easy and precise with a proton magnetometer. Search contractors, military forces and geologists world wide have done so with complete accuracy since the 1950`s. They have pinpointed where to find the wreckage, were to drill for oil and the exact location of that sub.
Simply walk east/west through the general area of the target noting the highest reading and make a long mark in the dirt at that spot. Your target will be very close directly to the north or south on this line.
Now walk from the south end of the target area towards the north on the line noting the highest reading and making a long mark in the sand. Your target will be right under that mark or a few feet to the north.
More search information
While searching you should investigate any area where the gamma reading rises or lowers more the 2 or 3 gamma’s.
Generally you would search by taking a reasonable size area maybe 200 feet by 200 feet and walk back and forth while moving over maybe 10 feet or so on each new pass.
It would take around 20 passes to cover this entire area.
In the search industry this tactic is called mowing the lawn. This proven method is used in searches with all types of remote sensing equipment. It is used for sonar search, visual search and also by our space probes to map the planet mars.
You would determine the distance to step over for the next pass by taking into consideration the weight of the target and the distance from the object that it could be sensed in its worst possible case scenario.
It maybe that the target is smaller that you thought. Or it may be laying at such an angle in relation to the earth’s field that it might be making a smaller disturbance in the field than it would if it were laying at any another angle.
Recommended reading list in order of importance.
1. The Discovery Handheld Proton Magnetometer Owners Manual. The latest updated version is at the Quantro Sensing web site. www.quantrosensing.com
2. Applications Manual for Portable Magnetometers by S. Brener. This may be available from Geometrics 395 Java Drive Sunnyvale, California 94086
3. Principles of Applied Geophysics by John Wiley and Sons, New York 1962.
3. Using a search engine on the World Wide Web search the word Magnetometer.
4. Try your local library. Who knows what they may have!
We want you to become an expert in the magnetic search field. The time you spend will be very rewarding.
Section 6. Tone earphone option.
The tone earphone is very useful and we recommend that it is ordered at the time the Discovery is purchased.
Do not plug any other headphone into the mag. Only the special headphones from Quantro Sensing will work.
It frees up your concentration from having to watch the gamma number readout to see a target. With the tone option you can listen for the target and concentrate more on where you’re searching and what is going on around you.
The earphone puck sounds a 200 Hz tone which sound like a medium to low growl. This tone is updated with each new reading of the earth’s magnetic field.
If the field stays the same the tone continues to growl at the same 200 Hz tone. If the gamma reading changes higher or lower then the tone steps a small percentage up or down per gamma reading change from the last gamma reading.
So if the gamma reading changes 5 gamma higher than the last reading the tone will move up x percentage in frequency to maybe 204 Hz.
If the next reading is 20 gammas higher than the last as it would be if you’re nearing a target the tone will step up again x percentage to maybe 233 Hz.
As you move away from a target the tone would step back down to the 200 Hz tone that it had started at.
The tone sound can only step up or down in tone to follow at the most a 250 gamma change. This is because of the fact that you have to keep the step or percent of change for a single gamma or two large enough to hear the difference.
When the discovery is first turned on the tone immediately starts growling at 200 Hz. Now it will wait while growling for the second gamma up date and it will than use this gamma number as its centered 200 Hz value.
If the gamma field is slowly rising as it does towards mid day or noon the tone will also slowly rise. You can turn the power switch off and then back on to reset the tone to the new higher base gamma field reading.
The same tactic of turning the power off and then back on can also be used if you are near a large target and the field has changed greatly.
Remember that when you reset the tone using the power switch you must wait for the third reading before you could possibly hear a change in the tone to follow the gamma readout.
Section 7. Care and warnings concerning the proper use of this instrument.
#1. Do not run the mag without fluid in the sensor. It will over heat the windings ruining the sensor. This is misuse and will not be covered under the warranty.
#2. Be careful not to yank on, step on or pinch the cables from the sensor or the electronics housing.
#3. Lay the mag on something soft to stop vibrations from damaging the unit when traveling in a boat or car.
#4. Do not allow the mag to “cook” in the hot sun. Toss a blanket over it if it must be in the sun when not in use.
#5. Do not rewire the power cord without using a fuse.
The proper fuse is 3 amp. Red is positive and Black is negative.
#6. Try to only use sensor fluid out of a plastic container to avoid spoiling the sensor with rust or micro small ferrous steel specks that maybe in the fluid.