MW41 Radiosonde System Documentation

LSC Documentation

Note: the RS92 sonde and GC25 Ground Check have been replaced by the newer RS41 sonde and RI41 ground check. The older instructions are provided as this equipment remains available.

  1. Connections Using the RS92-SGPL Sonde and GC25 Ground Check
  2. Connections Using the RS41 Sonde and RI41 Ground Check
  3. Using the MW41 Software and Completing the Ground Check
  4. Preparing the Sounding Balloon
  5. Attaching the Radiosonde and Launching
  6. Accessing Sounding Data

Official Vaisala Documentation

  1. Official Vaisala Getting Started Guide MW41 (PDF)
  2. Official Vaisala Online Help in Printed Format (PDF)
  3. Official Vaisala Technical Reference-MW41 Sounding System (PDF)
  4. Official Vasiala User’s Guide: RS41-SG and RS41-SGP (PDF)
  5. Official Vaisala Radiosonde RS41 Quick Guide (PDF)
  6. Official Vaisala Radiosonde RS92-SGP User’s Guide (PDF)
  7. Official Vaisala Radiosonde RS92 Quick Guide (PDF)

Connections Using the RS92-SGPL Sonde

Step 1. Connect the GS25 Ground Check to the Edgeport GC25. Using the serial cable connect the end labeled GC25 to the GC25 Ground Check and connect the end labeled EGC to the Edgeport GC25 into Port 1.
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Step 2. Connect the Edgeport GC25 to the laptop. Using the USB cable, connect the end labeled EGC to the Edgeport GC25 and the other end to the laptop USB port.
IMG_1316 IMG_1317

Step 3. Proceed with Step 3. in the Connections Using the RS41 Sonde and RI41 Ground Check instructions

Connections Using the RS41 Sonde and RI41 Ground Check

Step 1. Connect the RI41 Ground Check to the sounding laptop via the attached USB cable.

RI41 connection to laptop.
RI41 connection to laptop.

Step 2. Use the white patch cable labeled “SPS” on each end to connect the Sounding Processing Subsystem to the laptop. Connect one end of the cable to the Sounding Processing Subsystem port labeled “LAN1.” Connect the other end to the ethernet port on the laptop.
IMG_1303 SPS to laptop

Step 3. Using the coaxial cable connect the end labeled “UHF OUT” to the UHF Antenna receptor labeled “OUT”. Connect the other end of the cable labeled “UHF IN” to the Sounding Processing Subsystem receptor labeled “UHF Antenna.”

IMG_1308 IMG_1306 IMG_1307

Step 4. Using the GPS coaxial cable connect the end labeled “GPS IN” to the Sounding Processing Subsystem receptor labeled “GPS ANTENNA.” Note: the GPS antenna must be placed outside away from any obstructions.


Using the MW41 Software and Completing the Ground Check

Step 1. After all connections have been made turn on the computer. Note that the wireless device on the laptop must remain TURNED OFF at all times.

Step 2. Login to the laptop using the username and password on the top left of the laptop (above the keyboard)

Step 3. Start the MW41 application using the desktop icon.

Step 4. Login to the application using the appropriate username and password combination on the top right of the laptop (above the keyboard.

Step 5. If necessary, change the Radiosonde – workstation connection under Administration->Devices. This is needed if switching from the GC25 to RI41 ground check systems for the RS92-SGPL and RS41 sondes, respectively, between launches.
Set GC Type

Step 6. Start the radiosonde ground check following the system instructions (i.e. place the radiosonde on the RI41 ground check when the system indicates it is ready.
Preparing Sonde

Step 7. Confirm the radiosonde has been prepared and is ready for launch as indicated by the system.
Preperation Complete

Preparing the Sounding Balloon

Step 1. Attach the regulator to the helium tank. Be careful not to cross the threads or over tighten. There are two regulators available, either one will work.

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Step 2. Check that the valve is in the closed position.


Step 3. Fit the balloon securely over the wooden inflation nozzle. One person should securely hold the balloon on the wooden inflation nozzle.

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Step 4. Open the valve on the helium tank and on the regulator (note that the regulator valve is reverse (left is closed, right is open).

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Step 5. Open the valve on the inflation hose and allow the balloon to inflate. The tank pressure should drop by ~400 psi (2750 kPA) to fully inflate the balloon.

IMG_1321 IMG_1329

Attaching the Radiosonde and Launching

Step 1. Follow the Vaisala Radiosonde RS41 Quick Guide instructions (or the instructions on the outer packaging of the radiosonde to connect the unwinder stick to the radiosonde.

Step 2. Attach the radiosonde to the balloon by sliding the balloon end through the unwinder and fold the balloon over.
IMG_1404 IMG_1405

Step 3. Use a zip tie to tightly secure the balloon to the unwinder. Be sure to cutoff any excess length of the zip cord so that it does not puncture the balloon.
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Step 4. Move the balloon and attached radiosonde/unwinder away from any buildings and/or obstacles.

Step 5. Hold the balloon above your head and the radiosonde away from your body.

Step 6. Let go.

Set Surface Weather Observation Values

Step 1. Once the balloon is launched, the MW41 software automatically prompts for the current surface weather observation values. These values can be taken with a Kestrel weather instrument, as explained in the following steps.

Step 2. On the Kestrel, make sure Sync Baro or Sync Alt are set to Off.

Step 3. Allow the Kestrel to become acclimatized to outdoor conditions. This can be done quickly by gently waving the Kestrel around, without covering the sensors, allowing for adequate airflow. This typically takes a couple minutes. The Kestrel is acclimatized when the temperature, dewpoint, humidity and pressure have stabilized.

Step 4. Navigate to the Baro screen and set the actual reference altitude: 1000 feet for the Weather Deck. Alternately, a GPS device can be used to determine the correct altitude. Exit out of the reference altitude setting screen.

Step 5. Note the barometric pressure that is now shown on the main Baro screen.

Step 6. Go to the Altitude screen and set the reference barometric pressure to match the pressure that was shown on the Baro screen.

Step 7. Go back to the Baro screen and set the reference altitude to zero (0) by pressing the left arrow to lower the reference altitude. The pressure displayed is now the station pressure (i.e. NOT sea level pressure). Enter thhis station pressure value in the Pressure field on the MW41 software.

Step 8. Enter the Temperature (degrees Celsius) and Humidity values.

Step 9. Enter the wind direction value. This can be determined by using the LSC01 station on Vail Hill, or by using a compass (subtract magnetic north, approximately 15 degrees).

Step 10. Enter the wind speed value (meters/second).

Accessing Sounding Data

Step 1. You can monitor the live sounding data via Sounding->Sounding Status in the MW41 software.

Sounding Monitoring
Sounding Monitoring

Step 2. Select “Archive” to generate sounding data in text form from the past soundings. Proceed to Step. 4 for a currently open sounding.

Step 3. In the Archive window select the sounding of interest and select then Open button on the lower left. You will be shown the Sounding for the selected date.

Sounding archive.
Sounding archive.

Step 4. Select Sounding->Messages. If it is not already available in the list of Messages, select “Create a message”, select “Formout for the type, and then select “Create.”

Create new sounding message.
Create new sounding message.

Step 5. A SHARPpy-readable text file is automatically generated when the radiosonde ascends above 100 hPa (same format as SPC’s Tabular Sounding Data. This file is located in D:\Messages and is named with the date and time (Zulu) of the launch. Other file formats can also be generated by selecting different messages from the list clicking Download. Follow the IE prompt to download the file to the computer.

Step 6. These text files can be saved to a USB or accessed directly as needed. Also see an archive of LSC Observed Soundings