After almost 2 years, the world record of 702 km (436 miles) has been broken. Not once but twice. For a long time this record which was set on 26th of August 2017, seemed nearly impossible to break, until the Servet IV mission was launched. On 13th of July 2019, the record was broken by 39 km, setting a new record distance of 741 km. Interestingly, this record only held for 5 hours as another new world record was set with an astonishing distance of 766 km (476 miles).

LoRaWAN is a Low Power, Wide Area (LPWA) networking technology, designed for low-powered devices to communicate with Internet-connected application over long range wireless connections using the unlicensed ISM radio bands. The LoRaWAN protocols are defined by the LoRa Alliance and formalized in the LoRaWAN Specification which can be downloaded on the LoRa Alliance website. The Things Network runs the world's largest open LoRaWAN network, currently available in over 100 countries around the world.

Servet is a citizen science project supported by Ibercivis and a growing team of volunteers. The project’s aim is to give people the opportunity to conduct stratospheric experiments using weather balloons. Since the year 2017, four missions have been completed, including the Servet IV.

7 balloons are launched in Alfamen, Spain

On Saturday the 13th of July 2019, 7 balloons of different sizes were launched from Alfamen (Zaragoza, Spain) carrying a total of 20 experiments from different people, from young talents to veteran makers. The balloons were tracked using The Things Network, plain LoRa® and by APRS and satellite using Spot.

Veteran makers David Cuartielles, Enrique Torres and Alejandro Suarez weigh a probe

World Record Breaker 1 - 741 km

The probe named PaPe I, built by Jose Manuel Cuesta, was developed with only one goal in mind. This had to be accomplished by using three directional 3D printed Moxon Antennas placed at 120º and a reaction wheel (a type of flywheel used primarily by spacecraft for altitude control) to stabilize the probe and to prevent it from spinning. It is crucial to keep the probe from spinning as LoRaWAN transmissions using high Spreading Factors can take up about a second.

Each antenna had its own transmitter. The first antenna was connected to an ESP32 microcontroller with an RFM95W LoRa module, the second with an ESP8266 and RFM95W, the last one with an ASME Lion SOM based on Atmel D21. The structure of the probe is 3D printed. It’s a modular design made in FreeCAD. (Source files can be found on GitHub).

* Germán Martín and Jose Manuel Cuesta are looking at the PaPe I*

The previous 702k record was beaten on several occasions during the flight, with connections to different sites across Spain, France and Portugal. Finally, the record was established at 741 km when the probe contacted Lisboa.

Balloon track, visualized by TTN Mapper source

2019-07-13 14:13:23 Node: hab2019pape Received by gateway: 00023DFFFE0F5945 Location accuracy: 0.00 RSSI: -118.00 SNR: -13.50 DR: SF10BW125 Distance: 741095.27m Altitude: 33118.0m

Nuno Cruz from Lisbon, confirmed that the gateway was correctly placed on the map. The LORIX One gateway is supported by a research group (Future Internet Technologies) from ISEL (Instituto Superior de Engenharia de Lisboa), a Lisbon engineering Polytechnic Institute.

Photo of the LORIX One gateway that received the LoRaWAN message

World Record Breaker 2 - 766 km

At the same time Diana I, a small probe made by Enrique Torres from the computer architecture research group of the University of Zaragoza, was aimed at reaching the highest possible altitude (>40 000m). For doing so, the balloon’s lift and capsule weight were optimized up to the grams. The climb was going to take extremely long (over 10 hours), and the route was likely to be very long, creating a high risk of losing the probe completely. The device was realized with a TTGO node with LoRa module because of its price (€17), availability, weight and low power consumption. The Things Network was selected as the platform due to its ease of use, broad possibilities of integrations and the countless number of connected gateways.

Launch of Diana I

Likely due to the incoming storm, the probe didn't reach the desired altitude and went up to 28 km on Saturday. At 9 p.m. the balloon even descended down to "only" 18 km and stopped transmitting LoRaWAN packets, the rain might have effected the electronics. Surprisingly, on Monday at 12 p.m., the balloon flew by the Azores at 33200 meters, sending its last transmission before it got lost around 6 p.m. somewhere in the Atlantic, 54 hours after its launch.

Balloon track, visualized by TTN Mapper source

The probe, with a weight of 106 grams was equipped with a BME280 (low power temperature, humidity and barometric pressure) and a GPS. It transmitted approximately every 60000 ms cycling between SF7, SF9 and SF11 using a transmission power of 14dBm (25mW). SF12 was not used due to the shaky nature of the balloon and the time needed to transmit.

The 2dbi vertical bazooka dipole antenna, with two 8.4cm elements was handmade and adjusted with a low cost analyzer by Arturo Hermosa member of the IEEE student branch of the Escuela de Ingeniería y Arquitectura of the Universidad de Zaragoza.

At a temperature of -16.5 degrees celsius, while the probe was flying only at 24859 meters above Ariza (Zaragoza, Spain), Diana's messages were received by 24 gateways. One of them was located at a ski resort, on a mountain 2253 meters high, and at an incredible distance of 766 km.

Maximum distance: 766 231 m

2019-07-13 19:31:23 Node: servet4high . Received by gateway: cea-chamrousse-gateway Location accuracy: 0.00 RSSI: -120 SNR: -14.25 DR: SF11BW125 Distance: 766231m Altitude: 24859m

JP Meijers, creator of TTNmapper confirmed the location of the gateway by looking at previous measurements.

Thanks to The Things Network community, the owners of the Kerlink gateway were contacted. Jander Nascimento from CEA declared: “That is for sure a great achievement and something great for a success story of the LoRaWAN protocol”. Levent Gurgen is in charge of the project that had the idea of putting this Kerlink gateway up there. The deployment was done in the context of the Wise-IoT European project for smart ski station experimentation. More details about the project can be found here (Chapter 2.5).

Kerlink gateway at a 766 km distance from Diana I

The new world record approaches the theoretical maximum a LoRaWAN packet can travel. Semtech’s LoRaWAN Academy argues that 800 km is the maximum distance in Europe, using 25mW transmission power in the 868Mhz ISM band. See LoRaWAN Academy, video radio propagation, from minute 15:00.

Waiting anxiously for the Servet V mission;

Jose Manuel Cuesta The Things Network Madrid

Enrique Torres The Things Network Zaragoza

Special thanks to:

Images of Servet thanks to Jorge Lizar & David. CEA for installing the gateway in such an amazing location. The town of Alfamen for hosting the event. JP Meijers for mapping the node on ttnmapper.org. Francisco Sanz from Ibercivis, eTopia, Bea, Nacho, Alejandro and many other Servet volunteers for making all this possible.

Hard to believe the distances of 741 and 766 km? Please have a look at the data:

- TTN Mapper RAW data of PaPe I

- TTN Mapper visualization of PaPe I

- TTN Mapper RAW data of Diana

- TTN Mapper visualization of Diana

- More information and visual materials

Learn more about LoRa Radio Propagation and find out about the theoretical maximum 800 km - LoRaWAN Academy

Getting started with LoRaWAN

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About The Things Network

The Things Network provides a global, open LoRaWAN network with a set of open tools to build your next IoT application at low cost, featuring maximum security and ready to scale. Through robust end-to-end encryption, a secure and collaborative Internet of Things network is built that spans across 100+ countries around the globe. Now operating thousands of gateways providing LoRaWAN coverage to millions of people.