IBAE Ao PREPARATIONS FOR SOUNDING 
the difference between pressure (1) and pressure (2) is 
4.4 = 8 clicks. 
.00 
After the setting has been made, the contact point will not be raised from 
the commutator before release. 
15.6 Release Point Contact Setting. Estimate from the pressure calibra- 
tion chart the pressure-contact setting to the nearest 0.1 contact corres- 
ponding to the pressure at release point (see JB4-4.3). Record the pres- 
sure-contact setting on WBAN-31A. 
16. Battery Time. Do not install the battery or if it is installed, dis- 
connect it when a delay of more thanfive minutes is expected before the 
balloon is released, If the radiosonde is equipped with a battery switch, 
open the switch instead of disconnecting the radiosonde from the battery. 
A minimum of two minutes should be allowed before release after the 
water-activated battery is again connected. 
17. Hypsometer Fluid. Fluid will be placed in the flask of the hypsom- 
eter radiosonde in accordance with instructions for the type radiosonde 
in use, 
18. Exposure Before Release. The sensing elements and the radio- 
sonde box adjust to changes in temperature quite rapidly. The time 
needed to tie the instrument to the train and get ready for the release 
will normally be sufficient for the radiosonde to be conditioned to the 
change of temperature from a warm room to the outside air. However, 
if the temperature difference between the baseline-check and the outside 
air exceeds 30°C, an exposure time in the outside air of at least 10 min- 
utes should be allowed. The radiosonde, whichis ready for release, will 
be conditioned to the outside air ina sheltered, unheated place, protected 
from rain or blowing snow. It will be placed in an upright position and 
have ample space for free circulation of airaround the radiosonde. 
19, Baseline-Check if Release is Delayed. Ifthe release is delayed for 
more than two hours after the radiosonde has been removed from the 
baseline-check box, anew baseline-check willbe made with a new battery 
and a new hygristor before the radiosonde is released. A new baseline- 
check will also be made if it is necessary to change over to another set 
of ground equipment or if substitutions are made in the major components 
of the ground equipment - frequency converter or recorder - during the 
period between the baseline-check and release. The Electronics Tech- 
nician will be consulted if a component has been changed, and there is a 
question whether a new baseline-check is needed. 
Lo il= 69 FMH#3 
