CHAPTER B2 
PREPARATIONS FOR SOUNDING 
dhe General, Before beginning preparations for a raob, the observer 
will familiarize himself with the wind and weather conditions and the ex- 
pected air traffic. He will consider the length of exposure time and 
warm-up time required for the various pieces of equipment, and he will 
determine the order in which the preliminary operations are to be per- 
formed. The order must be adapted to the arrangements and needs of 
the station and of the particular observation. Several of the operations 
can be carried on at the same time, and all must be started sufficiently 
early so that the release can be made on schedule. Check the recorder 
paper, data printer paper, and the ink supply to determine if there is 
enough to meet the needs of the current observation. 
Ze Preparation of Radiosonde for Baseline-Check. After the radio- 
sonde has been inspected and accepted for use in accordance with the in- 
structions in Chapter B1, it will be prepared for the baseline-check in 
accordance with the following instructions and those issued separately 
for the specific series of radiosondes. NOTE: If the radio-frequency 
check, specified in §B1-2.3, was made more than four days before the 
sounding, the radio-frequency check will be done againbefore the base- 
line-check. 
2.1 Activation of Battery. Each can of batteries contains a copy of 
activation instructions. These instructions must be strictly adhered to so 
that the life of the activated battery willnot be shortened nor damage be 
done to the battery. While wetting the battery, care should be taken to 
keep the battery socket away from the water. 
2.2 Battery Voltage Check. It is of utmost importance that the battery 
voltage be checked and thatitbe upto minimum voltage before the base- 
line-check or prior to inserting into the radiosonde, if a baseline check 
set with internal power supply is used for the baseline- check. 
2.2.1 Battery Under Load. After wetting, the battery must be placed 
under load for about five minutes inorder for the battery voltage to build 
up. The battery may be placed under load by connecting it to the radio- 
sonde or to the battery test set. Since the batteries from the various 
manufacturers differ in the speed with which their voltages build-up, a 
table should be kept to establish the minimum time needed for each type 
of battery to build up minimum voltage. Use the battery test set provided 
to check the battery voltage. Reject batteries that do not build up to min- 
imum voltages in the established period of time. If a battery starts to 
ok) B2-1 F MH#3 
