This flight went off without a hitch at 1623Z on June 4, 2000. The balloon performed perfectly (it was a 10-year old surplus weather balloon) and the payload returned lots of cool data. The temperature sensors were great, yielding 12-bit values accurate within 1 degree C. The absolute pressure sensor, while it did function, exhibited some odd behavior. First, its output dropped suddenly during ascent, which must be a glitch. Also, it "bottomed out" at 32 counts, and did not even get close to zero output even though the balloon kept on climbing. This was most likely the fault of the amplifier circuit between the sensor and the A/D input of the microcontroller.

Features of this payload:

• 8-bit microcontroller with A/D converter (Microchip PIC-12C671)
• Outside and inside wide-range temperature sensors (Dallas DS-1721)
• Absolute pressure sensor for approximate altitude (Lucas NPC-103)
• A data frame counter on downlink for aligning data sets
• Lithium 9v primary battery rather than alkaline
• Styrofoam and urethane insulation, plus soft foam for impact survival

Telemetry Listing of ITA-3 flight
Temperature Graph - note warming in stratosphere
Pressure Graph note discontinuity (?)

Specs of the ITA-3 balloon:

Envelope: 300g latex sounding balloon inflated to about 4 feet
Payload weight: 210g
Downlink: 28.636 MHz CW, 20 mW "fireball"
Time from launch to LOS: 2 hours 45 minutes

Telemetry format was as follows:

DE KA2QPG BALLOON ITA3 F06 PD2 O107 I14E BD9 PSE QSL AR

F 06 - Frame counter, increments on each data frame.
P D2 - Absolute air pressure sensor, 8-bit, 00h = vacuum
O 107 - Outside temp, 12-bit, 16.4375 degrees C. In 16ths of a degree.
I 14E - Inside temp, 20.875 degrees C, same format.
B D9 - Battery voltage, 8-bit, 8.5V. FFh = 10.0 V, 00h = 0.0 V