40 kHz wind measurement across extended acoustic paths
The BBFM-V40K is an ultrasonic wind speed and direction transducer for 2D and 3D ultrasonic anemometers, meteorological monitoring, ventilation airflow measurement and industrial duct monitoring. Its specified center frequency is 40 kHz ±5% and its reference range extends from 0.5 to 12 m.
The -3 dB half-power beam angle is 11.3° ±10%. This combination of path length and angular coverage should be evaluated when arranging opposing transducers and defining the measurement volume.
Verified technical specifications
| Parameter | Specification |
|---|---|
| Model | BBFM-V40K |
| Center frequency | 40 kHz ±5% |
| Recommended range | 0.5 to 12 m |
| Minimum impedance | 250 Ω ±20% |
| Capacitance | 4,000 pF ±20% at 1 kHz |
| Operating voltage | Peak voltage <1,500 Vpp |
| Operating temperature | -40 to +80°C |
| Pressure rating | ≤3 kgf or 0.3 MPa |
| Half-power beam angle | 11.3° ±10% at -3 dB |
| Housing material | Stainless steel |
| Mounting | Refer to the dimensional drawing |
| Protection rating | IP68 |
| Weight | 1,580 g ±5% with a 10 m ±0.3 m cable |
Array layout and electrical matching
For a 2D or 3D anemometer, define the path within the 0.5 to 12 m reference range while considering the 11.3° beam angle, airflow geometry, structural obstructions and transducer alignment.
The transmit and receive electronics should match the 250 Ω ±20% minimum impedance and 4,000 pF ±20% capacitance at 1 kHz. Applied peak voltage must remain below 1,500 Vpp.
Mechanical and environmental integration
Operation is specified from -40 to +80°C, up to 3 kgf or 0.3 MPa, and with IP68 protection. The stated 1,580 g ±5% weight applies to the 10 m ±0.3 m cable configuration, so supports and cable routing should be included in the mechanical design.
- 2D and 3D ultrasonic anemometers
- Meteorological monitoring
- Ventilation airflow measurement
- Industrial duct monitoring