(3)  For a warranty return, carefully re-open the side flap and insert the contamination shield holder and the shield back over the sensor boom. Ensure that the little peg on the holder is in the hole on the boom. Gently re-position the boom under the side cover to protect it from damage. Place the radiosonde back into the bag it was shipped in and seal it securely with tape. The station personnel should log the radiosonde’s problem on the WS Form B-29 "Radiosonde Report" and on the WS Form H-6 "Report of Defective Radiosondes" which is sent to the NLSC.

(4)  Open the battery container cover (Figure 2, item 6). Remove the battery (Figure 2, item 5). Carefully pull out the radiosonde battery connector wire leads.

B - Preparing the Battery

ACTIVATING THE BATTERY MUST BE DONE NO MORE THAN 20 MINUTES BEFORE RADIOSONDE RELEASE. EARLIER ACTIVATION MAY CAUSE THE BATTERY TO FAIL PREMATURELY DURING FLIGHT.

Figure 6: The battery must be immersed in water with at least 2" of water over the top.

(1)  Unfold the battery wrapper, and with scissors, cut the bag open along one edge of the bag (use caution to avoid cutting the wire leads), and remove the battery. Discard the bag.

(2)  Activate the battery by immersing it in clean, room temperature water (» 25° C) for NO LESS THAN 3 minutes. If you lose track of the elapsed immersion time, soak the battery longer than may be necessary to ensure that the three minute minimum is met. In other words, it is more desirable to soak the battery too long than not long enough. DO NOT use water that has a high mineral content or which has had iodine or large amounts of chlorine added. DO NOT immerse the battery connector located at the end of the wire leads. Immersion time should not be varied due to water temperature. The container used to hold the water must be made of glass, plastic or paper. DO NOT USE METAL CONTAINERS! THE WATER LEVEL MUST BE AT LEAST 2" (5 CM) ABOVE THE TOP OF THE BATTERY (see Figure 6).

(3)  After a MINIMUM OF 3 MINUTES, remove the battery from the water leaving as much water in the battery as possible. DO NOT SHAKE OR SQUEEZE WATER OUT OF THE BATTERY!

(4)  Do not discard the battery activation water but save it for re-use. If the water level gets too low for immersing the battery as shown in Figure 6, just add more water.

(5) Connect the battery and the radiosonde to the radiosonde battery tester (Figure 7). This is to ensure that the battery is under load to determine if the battery has reached a minimum of 15 Volts within 10 minutes. If the battery does not reach at least 15 Volts within 10 minutes, it should be rejected and replaced with a warranty replacement unit. The NWS Form B-29 and NWS Form H-6 should be annotated.

(6)  Wipe any excess water from the outside of the battery with a paper towel, and insert the battery into the battery container inside the radiosonde battery compartment as shown in Figure 2, item 5. Position the battery upright so that as you look at it from the sensor boom side of the sonde one of the battery wire attachment points is visible (see Figure 2, item 4). Close the battery container cover (see Figure 2, item 6).

(7)  Ensure that the folded radiosonde mailing bag is located between the battery container and the sonde cardboard sleeve on the right side of the battery (see Figure 8, item 1).

(8)  Insert and position the battery wire leads and connector (Figure 2, item 3) such that they are on top of the battery container cover (see Figure 8, item 2).

(9)  Close the flaps on the portion of the cardboard jacket over the battery and secure the flaps with the interlocking tabs and tape shut.

(1) AVOID TOUCHING THE SENSOR BOOM OR SENSORS ON THE BOOM WITH BARE FINGERS! Doing this can damage a thin coating on the boom which helps reduce water or ice build-up on the boom when the radiosonde is exposed to precipitation or high relative humidity during the flight. If you need to touch the boom, do so only along the edges of the boom outside of the bright silver coated area.

(2) To reposition the boom, bend the upper end of the flap (Figure 5, item 2) outward under the sensor boom so that the boom is positioned at a 30° upward angle to the side of the radiosonde package. A plastic pen may also be used to position the boom.

D - Tuning and Baselining the Radiosonde

Figure 9

(1) Place the radiosonde upright on a cardboard box or block of styrofoam and straighten the antenna so it is pointing down (see Figure 9). DO NOT place the radiosonde on its side or on metallic objects or surfaces! Doing so may cause improper tuning of the radiosonde and/or baselining failure.

(2)  Check the radiosonde radio frequency on the tracking equipment to see if the transmitter is functioning. All radiosondes are tuned at the factory to a frequency of 1680 ± 4MHz.

NOTE: DO NOT tune the radiosonde unless it is out of tune range by more than 5 MHz or there is requirement for a second release. This should be done only after the battery is placed in the radiosonde and after the ground receiver has warmed up.

(3)  If the frequency must be changed, open the flap (opposite the sensor boom) marked "+ -" on the radiosonde cover. Turn the tuning screw with a small non-metallic screwdriver. Turn the screw clockwise (towards the "-" mark) to lower the frequency, counterclockwise (towards the "+" mark) to raise the frequency. It is not necessary to turn the screw very much to cause a large change in frequency.

(4)  Follow the baselining and pre-release procedures discussed in Weather Service Handbook 10 and the Vaisala Micro-ART Training Guide.

(5)  After baselining is complete, check the radiosonde temperature and relative humidity (RH) readings appearing on the Micro-ART computer screen. If they appear to be in error (for example, the radiosonde RH shows 105% or the temperature shows +60° C) reject the radiosonde.

(6) If the radiosonde fails baselining, set the instrument aside for warranty return. For a warranty return, carefully re-open the side flap and insert the contamination shield back over the sensor boom. Ensure that the small silver cap is still on the humidity sensor (see Figure 5, item 1). IF THE CAP HAS FALLEN OFF, it may be carefully inserted back over the humidity sensor holding it with clean cloth or paper tissue. Gently re-position the boom under the side cover to protect it from damage. Place the radiosonde back into the bag it was shipped in and seal it securely with tape. The station personnel should log the radiosonde’s problem on the WS Form B-29 "Radiosonde Report" and on the WS Form H-6 "Report of Defective Radiosondes" which is sent to the NLSC.

Any radiosonde that is rejected shall be rechecked by another observer on the next shift or within no more than 24 hours of first being rejected. Under no circumstances should the same observer be the final person to reject the instrument. Personnel making the final rejection will fill out the WS Form H-6 whenever rejecting an instrument or a battery with all necessary information. Specific detail is required. Remarks such as "Failed Baseline" do not suffice. The operator must provide a specific reason why the instrument was rejected and how much the instrument was out of tolerance.

Sites experiencing problems with instruments from a given sleeve or box will not return any instrument that has not been thoroughly checked and found to be defective unless permission has been obtained beforehand from WSH personnel. Changes under the warranty plan now state that any instrument returned for warranty that is found to be non-defective will have a reconditioning fee accessed.

(7) Obtain a new radiosonde and repeat radiosonde preparation from the beginning.

E - Releasing the Radiosonde

DO NOT release the balloon with the radiosonde lying on the ground. Doing so may cause the radiosonde frequency shifts and/or erroneous temperature/RH data.

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