These instructions describe how to properly prepare the Sippican MkIIA GPS radiosonde. The sequence of these steps can vary from user to user. However, the same basic procedures apply. It is recommended that the observer develop a “method” of preparing the sonde. For example, this guide is presented as working each side by turning the sonde in a counter-clockwise direction. Whatever routine works best for the observer. Be careful to inspect the sensors. If they appear to be damaged, reject the sonde. See Chapter 6, Section A for radiosonde rejection procedures.
Total time of radiosonde preparation, including soaking the battery, battery warm-up, and baseline, requires a minimum of 15-20 MINUTES. It is recommended that a timer be used. Required materials include a radiosonde and a clear plastic battery bag.
To begin, remove the sonde from the plastic bag. Keep the tape from the bag. You will use it later. Remove the battery from the battery compartment. Use scissors to remove the battery from the foil bag. Throw the foil bag away. Soak the battery in water for 4 MINUTES. The battery should be completely submerged in an upright position. Make sure that the electrical connectors stay clear of the water—hang them over the side of the container (Figure 1.8). Wet connectors will cause the battery to short. Remove the covering off the double-sided tape on the battery compartment flap.
Figure 1.8—Radiosonde soaking in activation water. Note that the “TOP” label is facing up, and the battery is completely submerged except for the wire connectors.
Remove the humidity cap and inspect the hygristor. The hygristor should be oriented at an angle to the duct. If it is perpendicular, reject the sonde. If the sensor is acceptable, tape the humidity flap shut with one of the piece of tape that you saved from earlier.
The thermistor is delicate, so be careful. Lift up on both sides of the tape holding the thermistor. Carefully pull the tape and plastic covering off the sensor. Remove the