Precise measurement at a small price


Radiosonde DFM-09

  • Extremely light, small and robust
  • Reliable and precise measurements in all atmospheric layers
  • Large range thanks to the latest telemetry
  • Long battery life
  • Easy handling for daily sounding


Our popular little one − in use around the world

The state-of-the-art DFM-09 is one of the lightest and smallest radiosondes on the market and is also one of the most used radiosondes in the world. It was designed for precise and reliable measurement of temperature, humidity, air pressure, wind direction and wind speed. It is easy to use, making it the ideal instrument for daily sounding.

Technical data


< 100 g, ready to start


200 x 42 x 60 mm

Power supply

Lithium battery

Runtime integrated battery pack

> 140 min.

Wind finding

GPS (48 channels)


One full data set per second


< 10 kHz

Frequency range

400 … 406 MHz

Frequency deviation

+/- 3 kHz



Output power telemetry

100 mW, typical

Error correction telemetry

Code-spreading, interleaving

Wind finding options

C/A code GPS

Temperature resolution

0.1 °C

Temperature random error

< 0.2 °C

Humidity resolution

1 % rH

Humidity random error

< 4 % rH

Pressure accuracy

< 0.3 hPa

Geopotential height accuracy

< 10 m

Wind speed accuracy

< 0.2 m/s

Accuracy horizontal position

< 5 m

The first few metres of ascent pose the most risk for the radiosonde in the event of strong winds. Secure your ascent with one of our Unwinders. For more information click here.

Balloon Filling Units
We offer balloon filling units in different designs for filling balloons with helium or hydrogen and for varied balloon sizes. For more information click here.

Our high quality balloons are available in different sizes and ensure that your radiosonde reaches the desired height. For more information ask our sales team.

GRAW Videos

Ascent of the radiosonde DFM-09, headquarters Nuremberg

Other videos (customer videos, etc.)

Ascent of the radiosonde DFM-09, Budapest