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  1. 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.

    Block diagram of receiving station

    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.


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

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  2. 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.


    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.

    Presentation by Shaun JH1HNB

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

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  3. Adding a Bodnar GPS Disciplined Oscillator to a KiwiSDR

    With the release of WSJT-X 2.3.0 in September 2020, Steve Franke K9AN, Bill Somerville G4WJS, and Joe Taylor K1JT included a two new digital protocols called FST4 and FST4W. These two digital modes are the next evolution in low-power and long distance digital communications. These modes use four-level Gaussian frequency-shift keying (4-GFSK) modulation, which has smooth transitions between the four tones. This modulation is a bit easier to decode than regular WSPR, which uses 4-FSK modulation that has abrupt tone changes.

    FST4 is designed for keyboard-to-keyboard QSOs (similar to FT8), and FST4W is designed for beacon transmissions like the regular WSPR protocol that we use for picoballoons. The time periods for a single transmission are 120, 300, 900 ...

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  4. Installing a WSPR Receiver in Inuvik, NWT

    I recently set up a Weak Signal Propogation Reporter receiver in the town of Inuvik, NWT. I was there in the beginning of June 2022, just as the world was opening back up from the COVID-19 travel restrictions.

    New Inuvik town sign

    I thought Inuvik would be an interesting place, as it's at 68 degrees North latitude, which is above the Arctic Circle. During the summer, the sun never sets from May 25th to July 19th. In the winter, the sun doesn't rise from Dec 6th to Jan 5th. But the sun does get close enough to the horizon to have civil twilight, where the sun is less than 6 degrees below the horizon, so it's not completely dark all the time in the ...

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  5. 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.

    Fairbanks Vaisala autolauncher

    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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  6. 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!

    Oakland airport launch predictions

    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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  7. 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.

    Dempster Highway sign

    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.

    Hogen Hydrogen Generator

    I arrived just before ...

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  8. SOTA Activation of Vollmer Peak, W6/NC-298

    The San Francisco Radio Club organized another Summits on the Air event on 23 April 2022. For this "Simul-SOTA" event, there was 11 amateur radio operators activating 9 summits around the Bay Area. Steve W1EGG made a handy map with who was activating each peak:

    Simul-SOTA activations

    I activated Vollmer Peak, which is at the southern end of Tilden Park in the hills above Berkeley. Parking at the trailhead was easy in the morning, but by the time I left parking was nonexistent.

    The hike up was short, and the views were excellent. I could clearly see Mt. Tamalpais across the bay, which was activated by Vlad K6VVP.

    Hike up Vollmer Peak

    A lot of the other peaks that were activated that morning were visible from ...

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  9. Automated Recording of the HamSCI WWV/WWVH Science Signal for Sunrise Festival

    I'm planning on participating in the Sunrise Festival, which is a citizen science campaign run by the HamSCI group. Over the 30 April 2022 weekend, hams from all over North America are encouraged to record the WWV and WWVH Scientific Test Signal, transmitting at 8 and 48 minutes past the hour.

    I previously used my KiwiSDR to receive these signals, and luckily there is an easy API for the KiwiSDR that will allow us to save recordings from the SDR.


    kiwirecorder.py, written by John Seamons ZL/KF6VO, is a simple python program that remotely connects to a KiwiSDR and saves spectrum locally. The output file can be demodulated audio (SSB or AM) like you get from a ...

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