A company called Sippican makes the Microsonde IIA radiosonde. Sippican is owned by Lockheed Martin. Here is a brief description of a radiosonde from the sippican website.
A radiosonde is a meteorological device launched from the ground. The radiosonde measures pressure, temperature, relative humidity, wind speed, and wind direction from the surface to approximately 100,000 feet.
The radiosonde is carried into the upper atmosphere by a balloon, filled with either hydrogen or helium gas. At some point during the ascent the balloon bursts and the radiosonde falls back to the ground, along with the used balloon and parachute (if used).
Throughout the ascent the radiosonde regularly transmits the measurements of atmospheric pressure, temperature, and relative humidity to ground receiving equipment. This ground equipment, called a sounding system, processes and displays the radiosonde data for weather forecasters, then generates meteorological messages that are circulated to the worldwide weather network. Radiosondes can also be equipped with external sensors to measure additional parameters in the atmosphere, such as ozone concentration and radiation levels.
The Microsonde IIA transmits on 1 of 4 channels, this particular one was transmitting a 300 milliwatt FM signal on 1682 MHz that is roughly 180 KHz wide. It records temperature, humidity, pressure and GPS location using a built in GPS receiver. Wind data seems to be derived from the GPS data that is part of the telemetry. GPS and L-Band antennas are built right onto the circuit boards and therefore there is nothing external to the sonde except the temperature probe. The whole sonde weighs just 300 grams including dereeler and train cord.
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- Sippican Microsonde IIA Teardown
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- Trimble Copernicus II GPS Receiver.
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- 1/4 Watt GaAs HBT Amplifier.
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- Synthesizer and VCO.
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- Parachute assembly, including the train cord and dereeler. The dereeler is used during launch to allow launch person to manage train cord.
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- Here is the remains of the balloon. It was likely filled with Hydrogen but can also be filled with Helium.
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- Close up of the dereeler.
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- Microsonde IIA with battery. The battery is water activated and roughly 5 volts. The battery was hot upon retrieval and continued to be warm into the next day.
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- Note that a expired battery was used for this launch.
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- A message to whoever might find the device. A harmless weather device.
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- This sonde was launched from Oakland, CA at 16:00 local time (23:00 zulu) on August 8th, 2012.
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- Here is the location of the battery compartment, the small hole was likely created due to impact or removal from tree.
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- Another harmless weather device note. The temperature probe is actually the white wires sticking up from top of unit. Not sure why there is small hole indicating Temp on this side of box.
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- The serial number and sonde identification number.
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- This is a thin rod thermistor temperature probe.
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- The radiosonde is protected by a styrofoam box and also contains compartment for pre-paid postage and bag to return the sonde to NWS.
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- This is outside view of a fast response carbon hygristor. It is used to measure humidity.
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- Inside view the fast response carbon hygristor used to measure humidity.
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- This is the main PCB and contains CPU, humidity sensor, GPS receiver and other yet not understood components.
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- This is a capacitive-aneroid and it provides highly accurate continuous pressure measurements.
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- This is part of the sonde that is pointed to the earth and therefore is the L-Band transmitter eletronics.
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- This is the L-Band antenna. Perhaps some sort of patch antenna.
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- This is the GPS antenna. Perhaps some sort of patch antenna.
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- Main CPU board, GPS board, L-Band Transmitter board.
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- Mail bag and battery show in respective compartments.
