Figure 1-6.Tying the balloon neck to hold the
radiosonde instrument: (A) First square knot,
(B) looping the balloon neck and tying the
second square knot above the first, and (C)
attaching the unwinder to the balloon and tying
unwinder to balloon with excess cord.
U n d e r w h a t c i r c u m s t a n c e s s h o u l d a
meteorological balloon be conditioned before
What is the ideal ascension rate for a
What is the purpose in using a gas regulator?
How much cubic feet of helium is required to
achieve a free lift of 700 grams when using a
What must be done to the balloon when
conducting upper-air observations during
periods of precipitation or icing?
At sea, when is a parachute required to be
attached to the radiosonde?
What is the purpose of a balloon shroud?
PREPARATION OF THE RADIOSONDE
The lightweight, Vaisala RS-80 radiosondes are
unpacked from the protective envelopes and readied for
flight according to following the instructions provided
in the operators manual. An 18-volt battery is activated
by immersion in room-temperature tap water for 3
minutes. After lightly shaking off the excess water, the
battery is then plugged into the instrument to activate
the radiosonde. The radiosonde instrument is
automatically set to 403 MHz, but may be tuned from
400 to 406 MHz to avoid local interference. A small
screw located on the outside of the radiosonde can be
turned by using a small screwdriver to adjust the
frequency up or down.
The radiosonde should be placed outside, out of
direct sunlight and hot surfaces (decks/stacks), for five
minutes. This allows the sensors in the radiosonde to
stabilize prior to launch. Keep in mind that if the battery
is left to sit for more than 20 minutes, it may overheat
and become unstable, so time management of prelaunch
procedures is essential. Be sure to remove the plastic
cover from the sensor strip prior to releasing the
ENTRY OF CALIBRATION DATA
Each RS-80 radiosonde instrument is precalibrated
during manufacture and is supplied with a calibration
punch-tape. When each upper-air sounding is initiated,
the system prompts the operator to enter the calibration
punch-tape in the optical reader slot. This will ensure
that the signals received from the radiosonde are
properly interpreted by the system. The calibration