Notifications
Clear all
Search result for: id10=WA 0821 7001 0763 (FORTRESS) Pintu Baja 220 Way Seputih Lampung Tengah
Page 2 / 2
Prev
| # | Post Title | Result Info | Date | User | Forum |
| MagArrow Heading Error Compensation Flight FAQ | 1 Relevance | 2 years ago | Gretchen Schmauder | Application | |
| To perform a heading error compensation flight, fly the UAV with MagArrow attached up to 100-150 meters in a low gradient area. Hover the drone in a single spot and rotate it slowly through 360 degrees while logging magnetic data the with MagArrow. By keeping the drone location stationary the mag field will be also be constant. Thus we are only left with the sensor reading as a function of orientation. The MagArrow has two MFAM sensors, and the Way they are arranged ensures that when one sensor is in its dead zone the other is at its optimum orientation, and vice versa. The readings from the two sensors are combined to produce one magnetometer reading only. The two sensor readings are weighted such that as one sensor approaches its dead zone it is weighted much less (down to zero in the dead zone) while the optimum oriented sensor is weighted more fully. Thus you get only one magnetometer reading with no dead zones whatsoever. In addition, the weighted averaging of the sensors still does partial heading error cancelling. | |||||
| How deep can I explore with seismic refraction | 1 Relevance | 2 years ago | Gretchen Schmauder | General Seismograph Info | |
| Fundamentally, there is no limit. Seismic refraction has been used to image the MOHO. The depth of investigation is governed by the size of the source you use and the length of the seismic spread, which needs to be 4-5 times the depth of investigation. In practice, the most common use of seismic refraction is in shallow geotechnical, engineering, and groundwater investigations. Most of this is focused on the upper 20 meters or so. It is no coincidence that this happens to be around the upper limit of what can be accomplished with a hammer and plate. Every site is different – the specific geology and amount of cultural noise are important variables that ultimately govern depth of investigation for any given source – but 20 meters for a hammer and plate is a good rule of thumb. In general, deeper work requires larger sources such as accelerated weight drops or light explosives. The only Way to know for sure is to lay out your spread and see if you can get quality first breaks at the far geophones with 8-10 good swings with a sledgehammer. | |||||
| What is a seismic wave? A seismic ray? | 1 Relevance | 2 years ago | Gretchen Schmauder | General Seismograph Info | |
| A seismic wave is the transfer of energy through elastic earth materials by Way of particle oscillation/vibration. A seismic ray, or “wave front normal”, is an arrow drawn perpendicular to the seismic wave front to indicate the propagation direction at that point on the wave front. It is a convenient tool to help understand wave propagation through layered media; it is not something that exists in a physical sense. | |||||
| Steps to prolong the life of your OhmMapper system | 1 Relevance | 2 years ago | Gretchen Schmauder | Hardware | |
| The dipole cables are a high failure item as they are subjected to considerable wear and tear. Here are some steps that you can take to prolong the life of the system: Never lift the transmitter or receiver by the pulling on the Dipole cables. While setting up the system, it is extremely important to remember that the transmitter and receiver can easily slip out of the white neoprene covers if you are not paying attention. This will cause them to hit the ground and break the yellow connector, or at the very least jam foreign debris into the connector. A good habit to get into is to carry the units with the nose (cone shape) pointed down, that Way they cannot slip out of the neoprene cover. Do not put undue stress by pulling on the system at angles greater than 45 degrees at any given point in the array. Always make broad turns or pick up the array to start a new line. Make sure that the transmitter and receiver are always facing the direction of travel. (The cone pointing towards the console/operator) This will eliminate the possibility of turning the array into a "plow" and placing excessive strains on the connectors, not to mention communication problems. By following these instructions you will find that the instrument's connectors will be able to withstand the strain incurred during normal usage. Of course there may be circumstances that make this difficult, but it is good to be aware of these issues. | |||||
| Do Cesium Vapor Magnetometers Require Calibration | 1 Relevance | 2 years ago | Gretchen Schmauder | General Magnetometer Info | |
| Our cesium-vapor magnetometers do not require periodic calibration in order to maintain the accuracy as described in our published specification when the instrument is operated within specified environmental ranges. Geometrics cesium-vapor magnetometers are manufactured and tested based on the discoveries and the basic designs of Carian Associates (U.S. Patent 3,071,721). This method of total magnetic field measurement relies upon the measurement of the optical absorption of a particular cesium spectral frequency by the cesium vapor enclosed in a small glass cell. This method is similar to those used in the measurement of atomic emission and absorption frequencies using spectroscopic reference cells. The technique thus relies on well-known fundamental quantum mechanical constants for accurate and precise measurement of the magnetic field. As a result, no adjustments to the sensor are needed in order to correct or maintain its accuracy and Geometrics sensor and sensor driver electronics are designed to either work correctly or to not work at all and to report both the strength of the magnetic field as well as the strength of the electrical signal produced by the working sensor. In this Way, the signal strength measurement provides a direct indication of the operational state of the magnetometer while it is running and serves to alert the operator if the magnetometer encounters environmental conditions that are outside of its operating range. Occasional maintenance of the instrument at Geometrics facility should be performed when the instrument's internal diagnostics indicate substandard performance as described in the operator's manual. Please contact Geometrics Support for technical advice and additional information pertaining to your specific model. | |||||
| Can a Magnetometer Detect Gold | 1 Relevance | 2 years ago | Gretchen Schmauder | General Magnetometer Info | |
| There are basically three types of "gold": low concentration disseminated gold in ore, placer gold deposits and solid gold such as that associated with treasure. Magnetometers are used to find disseminated gold by its association with mineralized zones which also contain magnetite or other magnetic minerals. Magnetometers are often used in conjunction with airborne electromagnetic surveys to find the conductive ore bodies. Placer gold is the type found in buried stream channels such as the gold which sparked the California gold-rush in 1849. Gold dust and magnetic minerals have been concentrated in river banks over thousands of years. Where there is gold there is often magnetite and therefore the magnetometer can be used to locate placer gold deposits. Gold treasure is a different story and being non-magnetic gold, silver, and other precious minerals are not directly detectable by the magnetometer. The magnetometer can only detect ferrous (iron or steel) objects. If the gold is stored in an iron box or has iron materials next to the gold (such as colonial ship ballast stones in the marine environment), there is the possibility of detecting the iron material. This is true for land and marine (sunken galleon) gold bullion. The vast majority of target search surveys are performed on a grid in a "lawn mower" back and forth manner to cover the area of interest. Lane spacing is dependent on target size (magnetic mass). At a sensor to target distance of 2 to 3 meters there will need to be at least 1-2 kilograms of iron. This can produce a 1-2 nT anomaly that is detectable in a magnetically clean environment. The ideal environment would be in a plowed farm field or the bottom of the ocean away from human activity i.e., away from a port or harbor. You will probably not be able to detect this small of an anomaly in a city or port location. The more iron mass there is, the better the chance of detecting it. Training to use the magnetometer can take 1-2 days depending on experience with setting up computerized survey equipment and a GPS. Processing the magnetic data requires several days of training and would require a geophysical background to interpret the final maps. We provide free software to make maps and estimate the target depth of burial (inversion). If you are unfamiliar with this procedure, we would recommend that you find a local geotechnical firm to look at the data to determine if there are anomalies that should be investigated further. Remembering that non-ferrous materials do not cause anomalies (gold, silver, copper, brass, aluminum, gems) you will be looking for anomalies either associated with the container OR associated with ground disturbance (i.e., gravesite). In this Way some anomalies can be detected where there has been an excavation such as a gravesite. In order to understand the process more fully, we strongly suggest that you download and read the Applications Manual for Portable Magnetometers. Other additional resources are available. Understanding how the magnetometer functions and how the earth’s field responds to distortions due to ferrous materials will help you make good decisions about how to interpret and use the data to direct recovery or exploration efforts. | |||||
| Iron Ore Exploration | 1 Relevance | 2 years ago | Gretchen Schmauder | General Magnetometer Info | |
| One of the primary uses of our magnetometers is mineral exploration. Iron ore is one of the easiest targets because of its magnetic properties. Because of this, magnetometer surveys are almost always part of the initial phase of any iron exploration program. Briefly stated, the exploration strategy is to use portable magnetometers to measure the magnetic field strength over the entire survey area by traversing it along many parallel survey lines with the magnetometer. This field work provides measurements that are used to construct a magnetic anomaly map. Using this map, an economic geologist or geophysicist will infer the probable location of iron concentrations. Based on their assessment, drilling or sampling sites are chosen and, using the chemical assay of the samples, the iron ore reserves are calculated. You or your customer should be working with a geologist or geophysicist who is familiar with the region where the prospect area is located. Conducting a magnetometer survey and making a useful anomaly map are inexpensive activities as compared with survey data interpretation, sampling, and assay work. If your customer wants to learn more about magnetic survey practice, a good Way to start is by downloading and reading the free Application Manual for Portable Magnetometers. | |||||
| Why does my MagArrow have 0 readings or missing records? | 1 Relevance | 2 years ago | Rui Zhang | Hardware | |
| There are many reasons causing 0 readings or missing records: 1. MagArrow is dead-zone-free. But this doesn't mean it can be operated in any environment. If the background magnetic field is outside its operating range (20-100uT) or its gradient is too large, MagArrow will have readings of 0 (or dropouts). Usually this happens when you test the instrument inside a building. One Way is to place the MagArrow on a wood/plastic table. 2. The default conversion of Survey Manager is NOT to include data points without locations. Inside a building, you may not have GPS signal, leading to missing records. This topic is also discussed in Missing records from magnetometer export. 3. If the 0 readings occur during a survey, especially consistently along a certain direction, you may want to check the operating status of 2 sensors inside the MagArrow. First, make sure your MagArrow embedded software is MagArrowSetup-3.0.1915-881 or later. If not, please go to our website MagArrow embedded software update, download and install the latest embedded software(instruction inside the downloaded zip file). Connect to the new webpage ( .). The "Operating status" of each magnetometer, as shown below, should be "OK". If not, please record the error code and power cycle. To finish the survey, please keep an eye on this status whenever the MagArrow returns to the base during the survey (power cycle if error). If the error occurs more than twice during your survey (make sure it is not an isolated event), please contact Geometrics and report the error code. Please note that for "Combined sensor" (dead-zone-free) MagArrows, there is ONLY one reading in Mag1. Mag2 Data Valid is always "NO". | |||||
| What are the differences between LCS050G (Low-Noise) vs. LCS100S (SuperMag) modules | 1 Relevance | 2 years ago | Gretchen Schmauder | Hardware | |
| Differences between LCS050G (Low-Noise) vs. LCS100S (SuperMag) modules Q. What is the difference between LCS050G (Low Noise) and LCS100S (SuperMag)? Is different firmware the only thing that separates the Low-Noise version from SuperMag version? Or are there mechanical differences in how the sensors are constructed? A.The firmware is different, but that is not the only difference. We also build our sensors in two different groups - A and B - to satisfy the different requirements for each version. Group A satisfies SuperMag specs, while group B meets the Low-Noise specs (please refer to the datasheet). Each SuperMag must have 2 Group A sensors. Q. The sensors in the SuperMag are physically mounted in a configuration to eliminate the dead zones. Could a customer mount their Low-Noise version of the sensors into the same 'no Dead Zone' configuration, then run a simple script to accept only good data so that if one sensor goes into a dead zone, the firmware will automatically switch to record the data from the second sensor? Obviously Geometrics performs some magic when combining the data in the firmware, but that doesn't necessarily preclude a customer from trying to make a "SuperMag" type system with their Low-Noise sensors, right? A. In principle, yes. Customers can write their own script to combine the readings from each sensor to achieve the dead-zone-free operation. However, smoothing out the combined reading when one sensor’s reading drops out is pretty tricky. In addition, the heading effect will be much worse (determined by the heading effect of individual sensors) if customers choose to combine individual magnetometer readings instead of using the SuperMag dead-zone-free mode. Q. Can I upgrade my Low-Noise sensors to the SuperMag version? Would I have to send my unit to Geometrics' Customer Support or could you simply provide the new firmware so that the instrument behaves like a SuperMag? A. Yes, it is possible to upgrade your firmware, but this process requires you to return the instrument to us. However, Geometrics will NOT guarantee the SuperMag specs in this case since LCS050G still has Group B sensors. The only Way to guarantee SuperMag specs is to purchase the SuperMag sensors. Please contact us us for more information. | |||||
Page 2 / 2
Prev
