Starlink at SimulaMet
In this blog post Senior Research Scientist Tarik Cicic is sharing the first experiences with setting up the Starlink kit newly acquired by CRNA.
Our team at Simula Metropolitan Center for Digital Engineering (SimulaMet) runs a permanent research activity on availability and performance evaluation of wireless access technologies, including cellular and satellite. The measurements form the basis for an annual report on the stability and performance of these networks. We have now acquired a Starlink kit and subscription for satellite internet access, to join the family of evaluated technologies in 2023.
Starlink is the new kid on the block—it has been available in southern Norway since summer 2022—representing a viable internet access alternative in many scenarios. The kit consists of a satellite antenna with cable, a home router, and a base. In addition we got ourselves a pole mount and a Ethernet RJ-45 adapter, in order to mount the antenna on the roof of our office building and connect it to the permanent measurement installation.
The kit arrived in December, a little like an early Christmas present. My office has a roof window, which is possible to tilt 90 degrees and get a fair view of the sky. Eagerly, I assembled the kit (which is a very simple procedure), downloaded the management app and tried to “get signal” in my office through that window, like in the figure below.
This did not work. Starlink requires a quite unrestricted view of the sky, which the roof window constraints way too much.
The second attempt was on a roof terrace, with a largely unobstructed view toward the south, where most satellites are expected to orbit. It looked like this:
To my surprise, this was still not good enough. The antenna did establish contact with the satellites, however the system still complained about the obstructed view. In particular, the house wall about 3m east of the antenna, about 3m tall, was a significant obstruction. The Starlink app has a great visibility display feature, clearly indicating the problem:
Despite the “interruptions expected every 47 seconds”, the connection was made, and Ookla Speedtest achieved download speed of about 25Mbps in this setting.
The third attempt finally gave an unobstructed view! This time the antenna was placed on a coffee table, and as far from the wall as possible (about 4m). Voila, 50Mbps download speed was achieved.
Network properties
Where does a Norwegian Starlink connection reach back to Earth? Using traceroute we localised the ground station to be in Germany. Furthermore, we notice that Starlink uses IPv6 when available:
Despite the German connection, Starlink assigned our installation an IP address geographically allocated to Norway (network 91.102.182.0/26). Starlink knows the installation address, which has to be provided during the ordering process, and possibly uses GPS to localise the installation. We believe they use Network Address Translation (NAT) to assign the Norwegian subscribers to the “right” network so that geographically restricted content like national television can be consumed.
Permanent Installation
After the initial testing we proceeded to install the antenna on its permanent location on the roof of our campus building. Here, the view of the sky is quite unrestricted, only our 5G antenna installation covering some of the horizont:
The red arrow indicates the Starlink antenna. The other antennas in the figure are 5G, a geostationary satellite and a Fixed Wireless Access antenna (on the same pole below the Starlink). All these are parts of our lab setup.
With fixed roof mount, the realised bandwidth increased significantly:
Upload on this first test was not great, and may improve as the system gets tuned in. The goal of our research project is to monitor and analyse the performance over time. The complete results will be published in the 11th annual report covering the measurements in 2023, which we encourage you to read. We realise this is too long a wait and plan to share early systematic results in this blog, so stay tuned!