Older articles:

1. 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.

   

   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 winter.

   From an RF perspective, I thought this would be a really interesting location for several reasons. What happens to HF propagation when the D layer is always present? Would 20 meters be alive all summer long? Conversely, what happens in the winter when it's only the E and F layers?

   Hardware

   The hardware for this receiver is almost identical ...

   Read More →

2. Simultaneous Multi-Band WSPR Decoding with KiwiSDR and WsprDaemon

   I've been interested in receiving Weak Signal Propagation Reporting (WSPR) signals recently, for two reasons. The first is that the picoballoons that we launch use WSPR for position information. Not only do I directly receive the picoballoons after we launch them, but I also use the WSPR network to check on their location around the world. I don't have a receiver in Europe, so I rely on other amateur radio operators to receive the balloon and post its location online, and I want to give back to the network.

   The second reason is that I'm curious about how far I can receive signals with my somewhat compromised city antenna. While my fan/parallel dipole antenna will never perform as well as the huge antenna farms other amateurs operate, I can work on making my station a bit better by reducing local noise or improving my antenna. Incremental changes is what I'm going for.

   Hardware Radio

   Soon after we launched the first few picoballoons, I started receiving WSPR packets with my Kenwood TS-2000 using WSJT-X. This radio is a good basic ...

   Read More →

3. Building a Multi-band Fan/Parallel Dipole Antenna

   Now that Solar Cycle 25 is upon us, I wanted to get active on the HF bands. My primary bands of interest are 40 and 20 meters, so I wanted to build a multi-band antenna for these frequencies. After some research, and wanting only one antenna connection for my Kenwood TS-2000 radio, I settled on a fan/parallel dipole antenna. It's very simple to build, and really hard to beat the performance of resonant dipoles.

   Choke Balun

   A balun is required when you are interfacing a BALanced device, such as a dipole antenna, to an UNbalanced device, such as a coaxial cable. Coaxial cables are unbalanced because from an RF perspective, there are actually 3 conductors in a coax cable: the center conductor, the inside of the shield, and the outside of the shield. The outside of the shield acts like another ground wire, and can bring RF energy and noise down into the shack.

   This antenna and balun/choke design came from the 2008 ARRL Handbook for Radio Amateurs. I always encourage amateur radio operators to have ...

   Read More →

4. Picoballoon Launch 19: Midway Islands

   The SF-HAB group launched another picoballoon on December 11th, 2021, from the Berkeley Marina. The launch party was Martin W6MRR, Robert K6RGG, and Kazu AG6NS. This picoballoon used two clear Chinese party balloons with hydrogen gas for lift. Martin's custom electronics was used, with a WSPR transmitter that alternated 14 MHz (20 meters) and 10 MHz (30 meters).

   The aprs.fi callsign was W6MRR-22 using the WSPR to APRS bridge, and the WSPR callsign was W6MRR.

   

   This picoballoon floated between 9,900 and 11,100 meters (32.5k to 36.5k feet) for the duration of the flight, which is the perfect altitude for picoballoons. This is above most bad weather (rain and thunderstorms), but still low enough to be in the fast part of the jetstream.

   From Oakland, this picoballoon headed east at a pretty fast clip. In total, it traveled about 23,000 km (~17,000 miles) in 12 days, for an average speed of about 80 km/hr (~50 MPH).

   One interesting thing was that this balloon was not received on Dec 20th and 21st, when it ...

   Read More →

5. Picoballoon Launch 18: Almost around the World!

   While the previous Lodi picoballoon was floating over Mexico City, we launched another picoballoon from the southeast corner of the Berkeley Marina on November 13th, 2021. The launch party was Martin W6MRR, Robert K6RGG, Kazu AG6NS, and myself KF6ZEO.

   

   The forecast for the morning was no wind, and when we arrived at 10am the winds felt pretty calm. But after assembling the picoballoon train, it was apparent that even the very light breeze was too strong. The two clear Chinese party balloons were bent over, threatening to scrape against the ground.

   We waited almost 30 minutes for the winds to die down enough to release the picoballoon. During a bit of a lull in the wind, we walked across the parking lot while slowly releasing the balloon, kind of an in-motion release. This worked pretty well, and liftoff was at 10:30am local time (1830 UTC).

   The tracker electronics were built by Martin W6MRR, and we used two clear Chinese party balloons with hydrogen for lift. The WSPR callsign was W6MRR, and the APRS callsign was W6MRR-21.

   W6MRR-21 Flight Results ...

   Read More →

6. Picoballoon Launch 17: Lodi to Florida

   SF-HAB's Central Valley Division launched a picoballoon from Lodi, California, on Thursday November 11th, 2021. The launch party was David WB6TOU and Skip N6NFB. The tracker electronics used this time was a ZachTek WSPR Pico transmitter. Two Chinese party balloons were used for lift.

   

   

   The WSPR callsign for the balloon was N6NFB, and the APRS callsign was N6NFB-1.

   

   N6NFB-1 Flight Results

   Unfortunately, the tracker electronics did not power up on launch day, November 11th. We thought all was lost, but it awoke the next day in Maidenhead grid square DL58, which is ~1640 km (~885 mi) southeast of the launch location. The balloon was at an altitude between 9,900 and 11,100 meters (~32.4k to ~36.4k feet). Only 11 WSPR packets were received by the network on the second day.

   

   In total, only 29 packets from this picoballoon were received by the WSPR network, indicating that something was wrong with the transmitter or antenna. This balloon transmitted for 3 days total.

   The last packet received from this picoballoon on November 14th was in EL77, which is about ...

   Read More →

7. 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, we launched just after noon local time (1900 UTC). The launch party was Martin W6MRR and Robert K6RGG. The tracker turned on about an hour later at 2022 UTC.

   

   This picoballoon was interesting because the tracker alternated transmitting WSPR beacons on 20 meters (14 MHz) and 30 meters (10 MHz). The antenna was the standard 20m dipole, not tuned for ...

   Read More →

8. 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, which is higher than most bad weather but still in the jetstream.

   Something was definitely wrong with the tracker, because on Tuesday Sept 21st we only received a total of 7 packets from KFS and KPH (pdf). These two stations have have huge antennas right on the California coast near San Francisco, with excellent receivers. I ran a Hysplit prediction ...

   Read More →

9. 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 stuck in a tree, or just laying on the ground, we will never know. The single packet from the ground was received by Jari Perkiömäki OH6BG in Finland, approximately 3,700 km away.

   

   This picoballoon made it all the way from gridsquare CM87 to MN10. The center of MN10 is 63 degrees East longitude, which means that the balloon traveled ...

   Read More →