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1. Japan Radiosonde Recovery and Tracking

   In July 2023 another work trip took me to Hokkaido, Japan. I stayed in Obihiro, a city of about 165,000 people. I brought along a RTL-SDR dongle and mag-mount antenna, and if I had some free time, I would try and decode nearby radiosondes.

   From my earlier trip back in September 2022, I knew there was radiosondes launched from Sapporo twice a day. However, it was unclear if the Kushiro autolauncher had been replaced after the fire.

   

   After tracking the radiosondes in Hokkaido, I would travel to Tokyo for a few days and try and track them in the city, labeled "Tateno" in the above map.

   Tracking Hardware

   The equipment I use is very simple but effective, just a ...

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2. Fairbanks Radiosonde Receiving Station

   After my visit to Fairbanks, Alaska back in July 2022, I chatted with a friend who lives in Fairbanks. He agreed to host a radiosonde receiver at his house just north of town. Since I wasn't traveling to Fairbanks again in 2022, I shipped him all the parts necessary for the installation.

   

   This station is the standard Raspberry Pi and RTL-SDR Blog v3 that I have been shipping around to Houston and other sites. radiosonde_auto_rx runs inside a docker container, which makes it trivial to install and update the software. For remote monitoring and control, wireguard is the way to go.

   Antenna

   My go-to antenna for radiosonde receiving is a quarter-wave ground plane antenna. They are super easy ...

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3. Kushiro, Japan, Radiosonde Autolauncher

   A recent work trip brought me to Hokkaido, Japan. Taking a look at Sondehub beforehand, I noticed a few radiosonde launch sites on the island. My work would bring me closest to the Kushiro radiosonde launch site, so maybe if I had some free time I could go watch a launch.

   Research

   Before leaving for the trip, I contacted Shaun JH1HNB/KJ6VGQ, who was uploading radiosonde data to Sondehub. Shaun lives in Tokyo, and has written some blog posts about his experiences.

   Shaun gave a presentation (pdf) in February 2022 to the Tokyo International Amateur Radio Association. The presentation was about using radiosonde_auto_rx or a rdzTTGOsonde to receive radiosondes.

   

   I also did some research on the Japan Meteorological ...

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4. Fairbanks Radiosonde Autolauncher

   On the last day of my recent trip to Fairbanks, Alaska, I finished up work a bit early and headed to the airport to see a radiosonde launch. Looking at satellite imagery before my trip, the launch location has a few buildings so I thought it might be a manually-launched site like Inuvik or Newfoundland.

   However, when I arrived, through the fence I saw a Vaisala AS41 autolauncher, just like my local radiosonde launch site across the bay in Oakland, California. No one to talk with this trip.

   

   I arrived just before 3pm local time (2300 UTC), and the autolauncher was beeping away, indicating that the balloon was filling with hydrogen. I set up my mobile radiosonde_auto_rx station ...

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5. Houston TRACER Radiosondes

   Back in October 2021, the excellent team behind Sondehub added several features to the map. They added launch site locations, grabbed from the official NOAA database. Clicking on a particular launch site allowed a user to generate a weeks worth of flight predictions based on the most recent GFS run. Cool!

   

   The red lines on this prediction map of Oakland show the next 14 launches (7 days). As with any prediction of the future, the further out you go the worse the prediction.

   Reverse predictions (pdf) were also added, for predicting where a radiosonde was launched from. This feature would have been very helpful when I was trying to find the Monterey Bay launch location.

   Scrolling around the new map ...

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6. Inuvik Radiosonde Launch

   Now that the pandemic has tapered off a bit, I took another short trip up to Inuvik, NWT. While I was up there, I visited the Environment Canada Weather Station, and participated in a radiosonde launch.

   

   The big news out of Inuvik during this trip was that the road from the airport to the town has been paved! The road is much smoother, and I don't need to worry about windshield cracks every time a big truck passes.

   Since my 2016 visit, the site has been upgraded with modern equipment. The old Electrolyser Corporation hydrogen generator was replaced with a Proton Hogen unit, all housed in a modern building with explosion-proof light switches, electrical outlets, etc.

   

   I arrived just before ...

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7. Building a Quarter-Wave Ground Plane Antenna

   After my talk at Pacificon a few months ago, several people reached out to me about setting up a radiosonde receiving station at their house. They specifically had questions about the antenna and LNA, and after answering the same question a few times I decided to do a post about this topic.

   Building a 1/4 wave ground plane antenna is very easy to do. The overall design is simple, with a vertical element surrounded by a ground plane consisting of two or four wires bent down. Here are the dimensions for the VHF/UHF amateur radio bands (from the ARRL Handbook), but these dimensions can be scaled to any frequency.

   

   There are many online calculators that will give you ...

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8. 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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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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