Allow ~15 minutes before launch to prepare sounding.

1. Save radiosonde package because you will need the serial number stuck on it to fill in the sounding field log spreadsheet.
2. Do not touch sensor tongue.
3. Place Vaisala on the Vaisala ground check platform. This initializes the sounding and starts the program on the laptop.
   • If it doesn’t read the radiosonde after several minutes you may have to re-boot the entire system! We learned this on the July 5^th sonde launch at CHEESEHEAD.
4. A conditioning window should pop up. If a frequency window does not also pop-up, you can change the frequency in the conditioning window where it says “change” next to “frequency”. Manually choose a frequency where you see a trough. Note the frequency. Click “Apply”.
5. Allow the program to go through the ground checks – such that all the steps illuminate green. This can take up to 5 minutes.
6. ***Uncheck*** “Continue descending sounding” located at the bottom of the page under “In balloon burst:” and click “Apply”.
7. While the program goes through ground checks attached the regulator to the helium tank (or you can prepare beforehand).
8. Attaching the regulator:
   • Make sure the gauge on the left regulator is open. ***Valves are reversed***. Left is closed and Right is tighten.
   • Attach the cable to the Helium tank. Right hand gauge is for the Helium, Left hand gauge is attached to the regulator.
   • Use the wrench to tighten the nozzle a little bit to the helium tank.
9. Back inside the trailer, ground checks should be complete (all green). You can then take the sounding off the ground setup platform.
10. Snap into place the plastic stick that comes with the unwinder to the radiosonde. It’s like a puzzle piece. You will hear it snap into place.
11. Set it outside to activate the GPS.
    • To know that the GPS is working – a green tick mark symbol replaces the exclamation point.
12. Turn on the helium tank nozzle slowly and fill the balloon with 23 cu. ft. of helium – just add this amount to whatever value is present on the regulator.
13. Tie the balloon using 2 cable ties. One to tie the balloon off the helium, and another to tie the balloon to the radiosonde hook. Careful that you do not puncture a hole in the process.
14. Launch, making sure that your fingers are away from the spool hook.
15. Once launched, check that MW41 sounding program detected the launch and is receiving data.
16. Go to the desktop and enter metadata in the spreadsheet.
17. If balloon bursts below 500 hPa, launch another balloon.

• • Close-out program and restart by clicking “terminate sounding” button.
  • Initialize a new launch by putting a second radiosonde on the Vaisala ground check platform.
  • Be sure to choose a frequency different from the one used in the first launch.