9. Vandenberg Radiosonde Launches

   Just after setting up a remote receiving station in the hills above Santa Cruz for tracking radiosondes launched from Monterey Bay, I started noticing some weird stuff with the station. The station would detect a LMS6-403 radiosonde, but was unable to actually decode anything. The "jamming" signal was always on the same frequency of 400.259 MHz, and occurred daily around noon and midnight UTC.

   I speculated that it might be radiosondes from Vandenberg Space Force Base, approximately 300 km (~180 miles) south of the receiver along the coast of California. Although it would be cool to receive those radiosondes, the purpose of this station was to track the Monterey Bay radiosondes, so I put that frequency on the blacklist ...

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10. Newfoundland Radiosonde Launches

    I recently went on a work trip to Newfoundland, Canada. Checking Sondehub before I left, I saw that there were two radiosonde launching stations on the Island of Newfoundland, one on the west side in Stephenville, and the other on the far east end in St. John's. And as luck would have it, I was traveling to Lewisporte, which is on the Trans-Canada highway almost halfway between the two launching sites. I might be able to receive both sondes at the same time!

    As far as I could tell, the radiosondes launched at both of these sites were Graw DFM-09P (pdf), which transmit around 403 MHz. One interesting thing about these radiosondes is that they don't transmit a serial number ...

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11. Receiving Monterey Bay Radiosondes

    Taking a look at SondeHub one evening in early July 2021, I noticed some radiosondes down in the Monterey Bay, about 75 miles south of San Francisco. There seemed to be one per day in the afternoon on most days. The Naval Postgraduate School launches radiosondes very infrequently for their meteorology program, but these seemed to be launched from Watsonville or Salinas, not the main NPS campus in downtown Monterey.

    

    Then, on Monday July 12th, there was a flurry of radiosondes launched. I received a total of 5 of them from my station in Los Gatos. This station does not have good coverage in the direction of Monterey, and only starts receiving radiosondes when they rise up to 5,000 ...

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12. Containerized AIS Decoding with RTL-SDR Dongle

    It's been about 6 months since I started receiving AIS signals using a RTL-SDR Blog v3 dongle. My station is decoding between 35 and 70 ships at any given time, depending on time of day and how many ships there are in San Francisco Bay.

    The RTL-SDR Blog v3 dongle is a really inexpensive software-defined receiver. The "official" version costs about $25, and knockoff versions can be had for $10 or less. However, there's a reason why knockoff versions are less than half price, they use very cheap components and drift like crazy. I have several friends who bought the cheap version only to find that they just don't work, then purchased another knockoff that also didn't work. So save ...

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13. Two Radiosonde Recoveries in San Francisco

    The prevailing winds here in California blow from west to east, from the Pacific Ocean towards the Sierra Nevada mountains. Radiosondes launched from Oakland International Airport float in these winds, landing east of Oakland in the Central Valley, or south in the hills east of San Jose. I never recover the ones that land in the Central Valley, as driving 2 hours each direction during rush hour to recover a balloon is a bit too far for me. Only rarely do they land in populated areas in the Bay Area, and almost never on the Peninsula or in the city of San Francisco.

    This map (code below) shows the landing locations of all the radiosondes launched from Oakland since November ...

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14. Telemetry from an Oakland Radiosonde Floater

    In the beginning of March, something happened to the regular cadence of radiosonde launches from Oakland Airport. No balloon was launched on March 11th 2300 UTC, nor the next standard launch window on March 12th 1100 UTC (5am Pacific time). The SDM Ops Status Messages had a 10142 error for Oakland, which is ground equipment failure. I'm guessing that something broke or got jammed on their autolauncher, or maybe they ran out of hydrogen gas.

    By the afternoon of March 12th, the issue appeared to be resolved, and there was three launches in quick succession. The first and third balloons, S3231708 and S2321334, were normal, but the middle balloon slowly rose and leveled out around 35,000 meters (~115,000 ...

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15. An Atmospheric River of Radiosondes

    I recently installed a new antenna (see below), and checking SondeHub a few hours later I noticed a bunch of balloons west of Sacramento. Well, that's pretty interesting. There aren't any regular launches near Sacramento, so this must be something special. They seemed to be launched frequently, because when I stopped receiving one balloon I immediately start receiving the next.

    

    These balloons were far away! I guess this new antenna works a lot better than the old one. Trying to back out the launch location, it seemed like they were being launched from Beale AFB, which is directly east of Yuba City. Maybe a military project? The military does launch a lot of radiosondes, but those are usually in Arizona ...

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16. AIS Decoding with an RTL-SDR Blog v3 Dongle

    Update July 2021: Run rtl-ais and kplex in a docker container.

    At the conclusion of my last AIS blog post, I noted that the AIS receiving station I had set up was not sustainable for the long term. It was using a full hardware radio, and the software was running in a Windows 7 virtual machine on my personal laptop. Since AIS decoding is not super useful only when my laptop is powered on, a new station setup was needed.

    One option would be buying a dedicated Raspberry Pi with a dAISy Hat receiver. It's a dual-channel receiver that spits out UART serial NMEA frames to the Raspberry Pi, and costs $70, plus a Pi for $35. But that's a ...

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17. Listening to Fox-1Cliff (AO-95)

    I recently moved, and while packing up boxes I found my FunCube Pro+ receiver dongle. One of the many Pandemic Positives is that I have a lot of free time on my hands now, so I thought I would see if I could receive amateur satellites with this. Perusing the AMSAT live Oscar satellite status page, the only recently-launched CubeSat I could receive with the FunCube Pro+ dongle is AO-95, also known as Fox-1Cliff. And even then, the satellite appeared to be in Safe mode, with its transponder not working due to a failed receiver.

    Fox-1Cliff is named for Cliff Buttschardt K7RR, who was the amateur radio mentor for the PolySat project at Cal Poly. He was also heavily involved ...

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18. Two Months of Radiosonde Balloon Reception

    It's been two months since my first radiosonde recovery. In this post, I perform some analysis of the receiving stations at my apartment in San Francisco and my vacation home/parents place in Los Gatos. I also include the python code needed to generate your own plots.

    San Francisco Station

    Immediately after I got home from my first recovery, I converted my regular amateur radio station at my apartment to receive radiosondes. The external antenna is a Diamond X-50NA, which is a great amateur radio 5/8 wave 2m/70cm dual-band antenna. Coax up to the roof is about 80 ft of LMR-400, which is calculated at around 1.5 dB loss at 145 MHz and 2.5 dB at ...

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