9. 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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10. Pacificon 2021 Picoballoon and Radiosonde Presentation

    David WB6TOU, Martin W6MRR, and myself gave a presentation at the Pacificon, which is the annual ARRL Pacific Division ham radio conference held in San Ramon in the fall. Our presentation was titled "Picoballooning in the Bay Area: High Altitude Balloons, Picoballoons, and Radiosondes." Download the slides here.

    We also used this opportunity to launch the new SF-HAB website, which is a collection of how-tos, resources, and blog posts about our ballooning activities.

    The first third of the presentation was David talking about balloon mechanics, including how to prestrech, fill, measure, and release SBS-13 and cheap Aliexpress picoballoons. David launched two SBS-13 picoballoons from the Central Valley in winter 2021, one of which went 2.5 times around the world ...

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11. October 2021 Picoballoon Activities: Launches 12 thru 16

    In the beginning of October 2021, we had a flurry of launches from the Berkeley Marina. In the span of two weeks, we launched five balloons. All of the picoballoons woke up after launch, which means that we are getting better at building, testing, and launching picoballoons. But unfortunately, only one of them survived the first night and woke up the next day. We can't achieve our goal of going around the world if the picoballoons only last for one day!

    All of these picoballoons used the same custom electronics designed and built by Martin W6MRR. Two cheap Aliexpress 36-inch clear plastic balloons were used, with around 6 grams of free lift.

    Picoballoon Launch 12: K6RGG-11

    On Thursday, Sept 30th ...

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12. Picoballoon Launch 11: The Intermittent Picoballoon

    We launched again on Monday, September 20th, 2021, from our usual spot in the Berkeley Marina. The launch party was Martin W6MRR and Robert K6RGG, and the launch time was a bit later than usual at 11:30am Pacific time (1830 UTC). The picoballoon did not wake up on launch day. After our previous halfway around the world picoballoon, we were a bit dismayed to have another failed launch.

    

    But the following day it woke up! The picoballoon was meandering out in the Pacific Ocean in gridsquare CL79, somewhere between 9,900 and 11,100 meters (32.5k to 36.5k feet). While this is higher than most of our previous picoballoons, our ideal altitude is above 11,100 meters ...

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13. Picoballoon Launch 10: Halfway Around the World!

    At the beginning of Week 3 of Launch 10, we were getting excited that this balloon might circumnavigate the globe. The prediction made from the middle of Egypt showed strong winds would take the balloon to the West Coast within 5 days, maybe even crossing the -122 degree longitude line of our launch site before heading back out to sea.

    

    Flight Results

    Unfortunately, the picoballoon only survived two more days in the Middle East. In a situation eerily similar to W6MRR-17, a single packet was received from the ground in southwest Uzbekistan near the Turkmenistan border. The altitude reported was less than 900 meters (encoded in the WSPR power field as 0 dBm or 1 mW). Maybe the tracker was ...

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14. Picoballoon Launch 10: First Two Weeks

    After the previous three picoballoons did not turn on, we were really struggling to launch another. Was it worth it to build trackers, inflate balloons, and get up early to launch a balloon that never turned on? Luckily, we powered thru and launched another picoballoon on Saturday, Sept 4th, 2021, from our usual spot in the Berkeley Marina.

    The team met at 9am, which is a bit later than usual. It was still very cloudy, so the actual launch didn't happen until 9:50am Pacific time (1650 UTC). The launch party was Martin W6MRR, Rob NZ6J, and Robert K6RGG.

    

    

    The tracker was released in full sunlight without getting wet in the bay.

    Predictions

    Running HYSPLIT predictions on the morning of ...

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15. 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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16. Picoballoon Launch 9

    With the lessons learned from the failed previous launch, we decided to launch again the next weekend, August 28th, 2021. The launch party was Martin W6MRR, Justin, Robert K6RGG, and myself KF6ZEO. We launched again from the northwest corner of the Berkeley Marina.

    Our major lesson learned from the previous launch failure was there should be no fog or clouds at the launch site. Fog or clouds can condense on the balloon surface or tracker electronics, weighing down the picoballoon so it falls out of the sky. In addition, any winds or downdrafts associated with clouds can push the balloon into the ground.

    This morning there was no fog or clouds, but the smoke from the Caldor and Dixie fires ...

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17. Picoballoon Launch 7 and 8

    After a short break from the previous launch, we launched again on the morning of Saturday August 14th, 2021. The launch party was Martin W6MRR, Robert K6RGG, and myself KF6ZEO. We launched again from the northwest corner of the Berkeley Marina.

    Martin W6MRR had made some changes to the tracker PCB layout to try and mitigate GPS RFI issues, but since none of the standard layout changes made were helping at all, we decided to use an older board design that flew previously. We also decided to bring two trackers. Each tracker was identical electronics and balloon inflation, just different callsigns.

    

    Robert K6RGG brought his drone again and took some great video of both launches.

    Launches

    After powering on and ...

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18. 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 many 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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