MQ-501: Handheld Full-spectrum Quantum Meter

The MQ-501 is designed to be an easy-to-use handheld meter for spot-check measurements. The meter includes the AM-001 meter mounting bracket to mount the sensor on a horizontal plane to the meter and approximately 0.17 m of cable to accommodate the bracket length.

  • Product Name:Handheld Full-spectrum Quantum Meter
  • Item No.:MQ-501
  • Manufacturers:Apogee
  • Country of Origin:USA

The MQ-501 is designed to be an easy-to-use handheld meter for spot-check measurements. The meter includes the AM-001 meter mounting bracket to mount the sensor on a horizontal plane to the meter and approximately 0.17 m of cable to accommodate the bracket length. The full-spectrum sensor incorporates a blue-enhanced silicon photodiode and custom optical filters with a rugged, self-cleaning sensor housing design, anodized aluminum body with acrylic diffuser. Typical applications include PPFD measurement over plant canopies in outdoor environments, greenhouses, and growth chambers, and reflected or under-canopy (transmitted) PPFD measurements in the same environments.

The meter has a sample and log mode, and will record an integrated daily total in mol m-2 d-1. Sample mode will record up to 99 manual measurements. Log mode will power the meter on/off to make a measurement every 30 seconds. Every 30 minutes the meter will average the sixty 30 second measurements and record the averaged value to memory. The meter can store up to 99 averages, once full it will start to overwrite the oldest measurement with new ones. An integrated daily total will be recorded from the 48 averaged measurements (making a 24 hr period). Sample and log measurements can be reviewed on the LCD display or by downloading the data to a computer, however, the integrated daily total can only be viewed by downloading the data to a computer. Downloading data to a computer requires the AC-100 communication cable (a standard USB cable will not work) and ApogeeAMS software. Comes with a free protective carrying case.


Calibration Uncertainty    ± 5 %

Measurement Range    0 to 4000 µmol mˉ² sˉ¹

Measurement Repeatability    Less than 0.5 %

Long-term Drift (Non-stability)    Less than 2 % per year

Non-linearity    Less than 1 % (up to 4000 µmol mˉ² sˉ¹)

Response Time    Less than 1 ms

Field of View    180°

Spectral Range    389 to 692 nm ± 5 nm (wavelengths where response is greater than 50 % of maximum)

Directional (Cosine) Response    ± 5 % at 75°zenith angle

Azimuth Error    Less than 0.5 %

Tilt Error    Less than 0.5 %

Temperature Response    -0.11 ± 0.03 % Cˉ¹

Uncertainty in Daily Total    Less than 5 %

Detector    Blue-enhance silicon photodiode

Housing    Anodized aluminum body with acrylic diffuser

IP Rating    IP68

Operating Environment    0 to 50 C, less than 90 % non-condensing relative humidity up to 30 C, less than 70 % non-condensing relative humidity from 30 to 50 C, separate sensors can be submerged in water up to depth of 30 m

Meter Dimensions    126 mm length, 70 mm width, 24 mm height

Sensor Dimensions    24 mm diameter, 37 mm height

Mass    180 g

Cable    Approximately 0.17 m of shielded, twisted-pair wire with santoprene rubber jacket (high water resistance, high UV stability, flexibility in cold conditions)

Warranty    4 years against defects in materials and workmanship