MALÅ’s range of High Frequency (HF) Antennas offer the best imaging solution with the highest resolution available. These antennas are primarily used for high precision measurements and surveys, such as Non-Destructive Test (NDT), imaging of concrete, forensics, road surveys, layer thickness or other applications requiring high resolution measurements and images.
The MALÅ HF Antennas offer a reliable and non-destructive way of gathering subsurface information accurately, efficiently and in real time, for both metallic and non-metallic features such as rebar, conduits, wiring, plastic pipes, post-tension cables, voids and more.
The MALÅ 1.2 GHz and MALÅ 1.6 GHz HF Antennas are also available with a built-in, fully integrated 50/60 Hz sensor option (EM) to aid in the detection and location of energized cables and conduits within the structure under investigation. MALÅ was the first GPR manufacturer to offer this unique combination which can provide an extra measure of safety to any project.
The MALÅ 1.2 GHz HF Antenna is a high resolution antenna used for high quality radar measurements, with the deepest penetration in the HF range. It is commonly used for concrete, reinforcement studies and for road mapping and quality assurance.
The MALÅ 1.6 GHz HF Antenna is a high resolution antenna used for high quality radar measurements, with medium penetration in the HF range. It is commonly used for concrete, reinforcement studies and for road mapping and quality assurance.
The 2.3 GHz antenna is a high resolution antenna used for the high quality radar measurements; it offers the highest resolution for shallow investigations in the HF range. It is commonly used for concrete, reinforcement studies and for road mapping and quality assurance.
Tunnel Assessment Surveys:
To investigate possible quality deterioration within and above tunnels, GPR has proven to be an effective tool. When using GPR the condition of lining, location of hidden construction shafts, voids and delimination can be made both safe and cost-effective.
"We purchased our first MALÅ GPR unit in 2006 and we still use it daily, mainly for concrete inspections inside road tunnels. The unit is continuously exposed to both dust and humidity but it always works and delivers results. We are truly impressed with the quality of this unit"
Shanxi Highway Central Laboratory, China
Ground Penetrating Radar is an effective tool for detection of embedded rebar in concrete floors and walls. GPR can detect the depth and orientation of electrical conduit, utility cables and water lines.
Investigation of the Internal Structure of a Brick Chimney:
To show how air filled holes of cavities within buildings or other structures can appear on a GPR scan, investigations were made on different sides of a brick chimney to see if it was possible to detect its internal pipes, used for ventilation or smoke. The chimney is constructed of bricks and contains six different pipes at the top of the chimney. Not all these pipes are however going from bottom to top of the chimney. Instead they start at different levels within the building. A simple sketch of the chimney top is given at right. The red mark shows the location of an aluminium pipe within one of the chimney pipes.
Void Detection in Concrete:
Concrete professionals and engineers are interested in detecting the presence of voids that can impact the structural stability of a concrete slab.
Slab Thickness Measurement:
GPR can determine and record the slab thickness for both slab-on-grade and suspended slabs, determine rebar depth to measure concrete cover in slabs, beams, and columns.
Key Advantages: GPR is a safer and less disruptive than X-Raying. GPR equipment is safe to use around people without any safety constraints or setup requirements. Because of these features, interruption of operations can be eliminated or minimized.
GPR is a great tool for concrete evaluation and to determine concrete deterioration, slab thickness, rebar spacing, bar elevation, and amount of concrete cover over the rebar.
• A fully integrated GPR solution for concrete imaging;
• Collecting data three different measurement modes;
• Providing the highest resolution and detail of data;
• Combines both GPR and EM technology simultaniously;
• Multiple antenna frequencies.
In-Slab Conduit Location:
GPR is used to locate electrical conduits embedded in or below slabs prior to saw cutting or core drilling, thereby minimizing the risk of electrocution to the operator and reducing the risk of building systems shutdowns.
Key Advantages: Accurate target location within a concrete slab on-grade, wall, or supported slab can be achieved more quickly, safely, and economically with GPR instead of other existing techniques.
Detection of Plastic Pipes in a Concrete Floor:
This application note describes the construction of a new building with the heating system made up of a water-heating pipe work inside the concrete floor. The plastic pipes (25mm in diameter) are fixated to an insulation material prior to pouring the concrete. However, after the concrete were cast, pipes were seen on top of the concrete in a certain part of the floor. This led to the need of inspection of the status of the rest of the floor, as a certain amount of concrete (at least 100mm) was needed to ensure an efficient and even heating distribution. Further on, interior walls are to be constructed on the floor, and these are nailed directly on the floor, so again there is a need for sufficient amount of concrete above the plastic pipes, to avoid puncture and leakage.
• Pulse repetition frequency: 100 kHz
• Data bits: 16
• Time stability: Better or equal than 60 ps
• Sampling frequency: 6-700 GHz
• Acquisition mode: Distance/time/manual, Grid measurements are controlled by remote controls on antenna/handle, with audio response
• Time Window: 0-70 nS
• Power supply: External 12V DC battery, AC/DC agg. Input 100-240 AC Output 13.2 V DC / 4.5 A
• Operating time: 6 hours
• Charger: Quick charger, automatic charge cycle 100-240 V AC input
• Charge time: 3-5 h (80-100%)
• Input device: Combined turn-push button
• On/Off: On by start button, Off by menu and button
• Screen: Transreflective 10.4” (CX11), weather resistant (IP65)
• Antenna compatibility: MALÅ High frequency series: 1.2 GHz, 1.2 GHz EM, 1.6 GHz, 1.6 GHz EM, 2.3 GHz
• Dimension: 410 x 210 x 55 mm + protruding details 40 mm
• Weight: 3.5 kg
• Operating temperature: -20oC to +50oC (-4oF to +122oF)
• Environmental: IP 65
• Data download: USB 2.0
• Data memory: 1 GB
Technical specifications for the MALÅ HF Antennas:
• Centre frequency: 1.2,1.6 and 2.3 GHZ
• Bandwidth: > 100 %
• Time window: > 50 ns
• Repetition rate: 100 kHz
• EM option: 50 Hz or 50/60 Hz sensors (sensitivity 300 uV, 14 bits)
• Dimension: 160x90x110 mm (1.6 GHz and 2.3 GHz) and 190x115x110 mm (1.2 GHz, 1.6+EM and 1.2+EM)
- 0.6 kg: 1.6 GHz and 2.3 GHz
- 1.0 kg: 1.2 GHz
- 1.2 kg: 1.6+EM and 1.2+EM
• Cable length: 4 m
• Operating time: 3 hours (with 12V battery)
• Operating temperature: -20 to + 50 0C
• Control Unit: MALÅ CX or MALÅ ProEx control units
• Data acquisition: MALÅ CX or MALÅ XV Monitor (both preferred) or other laptop with MALÅ Ground Vision 2 software
• Environmental: IP65
• Options: MALÅ HF cart, single wheel encoder, Extension handle, 10 m extension cable, split box for tomography applications