chipped, scratched, or finger-
smoke. This pilot balloon may also be
used when only a few clouds, which
are not increasing, are present.
(3) The assembly of the radiosonde set
(b) Black pilot balloons stand out most
should be scheduled in accordance with
clearly in an overcast sky condition of
the required time of release. A time in-
clouds or a dense haze aloft. Regard-
terval of 20 minutes is allowed for the
less of other sky conditions, a black
activation of the battery and production
pilot balloon will give the best results
of full power. After activation, the bat-
in the early morning (at sunrise) or in
tery is connected to the plug provided on
the evening (at sunset).
the Radiosonde Baseline Check Set AN/
(c) Red pilot balloons are used primarily
when the sky is partly cloudy with a
c. Baseline Check Procedures.
blue or cloudy background. This pilot
(1) After the radiosonde unit is visually in-
balloon may also be used when sky
spected for material defects, prepare the
conditions are indefinite or changeable.
radiosonde set for a baseline check.
(3) Prepare the pilot balloons for inflation.
(2) Turn the power switch of Radiosonde
If the pilot balloon is more than 1 year
Baseline Check Set AN/GMM-1 to ON.
old, conditioning may be required to pre-
The fan, the heater, and light switches
vent premature bursting.
will operate but the heater will not oper-
(4) If the pilot balloon is to be released at
ate unless the fan is on. Allow the base-
night, AR 385-70 and AFR 55-73 re-
line check set to stabilize for at least 20
quire the use of Lighting Unit ML-608
and Parachute ML-609. The balloon train
(3) Place the test leads of the radiosonde set
is prepared as follows:
into the baseline check set terminal strip,
(a) Inflate the pilot balloon.
and set the selector switch of the baseline
(b) Unfold the lighting unit parachute;
check set control unit to REF.
check the paper for rips, holes, or
tangles in the shroud lines, and tie the
d. Baseline Check Using Radiosonde Recorder
cord attached to the lighting unit para-
chute to the pilot balloon neck.
(1) With the baseline check set selector
(c) Prepare the lighting unit in accord-
switch set to REF, adjust the printing
ance with instructions on the can.
circuit with the Control Panel C-834/
(d) Tie one end of a 5-foot cord to the
TMQ5 REC ADJ control knob to print
battery tabs, and the other end of the
at 95.0 recorder divisions on the Fre-
cord to the bottom of the lighting unit
quency-Recorder Time graph.
parachute shroud lines.
(2) Place the baseline check set selector
switch at TEMP for approximately 15
b. Balloon Launching Site (Electronic Observa
seconds, then at HUM for approximately
(1) Perform the preoperational checks on the
(3) With the Control Panel C834/TMQ-5
rawin set as indicated in TM 116660-
selector switch set to SIG, mark, with a
pencil, the respective traces, T for tem-
(2) Obtain current temperatures from the
perature, H for humidity on the Fre-
wet and dry bulb thermometers at the
quency-Recorder Time graph.
plotting station site. These will be used
(4) Place the baseline check set control
when adjusting and performing the base-
switch at AUTO, the Control Panel C-
line check of the radiosonde set.
834/TMQ5 selector switch at SIG, and
proceed with the baseline check until re-
quirements are met as given in the stand-
Be careful to handle the sensing
ard operating procedures.
elements by the edges (humid-
(5) When procedures given in (4) above have
ity) or lead wires (tempera-
been completed, Control Recorder C-577/
ture) when installing these units
GMD-1 records control switch is set to
in the modulator. Reject broken,