WX Sonde #2 Tracked and Recovered

Once again, we’ve been lucky enough to track and retrieve another “Harmless Weather Device”! This weather Sonde was launched from Oakland CA and eventually landed just East of the Sacramento Airport (SMF) in an open agricultural field. Chase vehicle driver and receiving equipment managed by Trango. Real time navigation and Sonde path modeling managed by r00t. And now, the rest of the story.

Since this Sonde was considered “local” the chase vehicle didn’t actually need to leave until the balloon burst (29,477 meters). Here is a Google Earth snapshot of the overall path of the Sonde starting when the receiving equipment acquired the signal to when it finally landed, hours later.

The overall path of sonde from Oakland to landing.

Here is a elevation profile that gives you an idea of the traveled distance, altitude and associated ascent and descent rates.

Overall elevation profile for Sonde.

The Sonde made a very comfortable and “clean” landing in a nice open field. In the screenshot below you can see the landing location and also the path as the Sonde was “walked” to the chase vehicle (Trango Label) with the transmitter and GPS location still sending to the receiving equipment (located in the chase vehicle).

Final landing and retrieval location.

The decoding and tracking software written by r00t (also the Chief Navigator) is what enables these Sondes to be located and retrieved. The transmitting frequency is located in the L-Band (1680 MHz) and so after the landing there is not much signal propagation, so you really need to know where they landed and that is exactly what r00t’s custom software does perfectly. Here is a screenshot of the GUI output, where you can see the final GPA location along with lots of other good info (including the serial number/ID of the Sonde).

Sonde Tracking Window.

And of course, a short video gives you an idea of the retrieval process.

Here are a couple of pictures of the actual recovered Sonde, showing the launch label and also the manufacturers sticker with model/serial number to match up with GUI output.

Label including location and time of launch.

Model and serial number of sonde.

Category(s): Sonde
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4 Responses to WX Sonde #2 Tracked and Recovered

  1. How important is it to have a front end noise figure below 5dB? With coax losses I net out at about 5-6dB noise figure. I’ve calculated the free-space path loss and assuming a sonde transmit power of +24dBm I predict the receive signal strength for a sonde 160km away to be about -118dBm. So I should be able to just *barely* hear one at my home using a zero dB gain antenna. This of course assumes favorable winds. Balloon trajectory can be estimated from this link:
    http://weather.uwyo.edu/polar/balloon_traj.html

    Regards,
    -Charlie

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