How much of the sky can be obstructed for Starlink to still work without connectivity breaks (in Germany)? This has been one of the most important questions I had about Starlink before I could try it out on my own. Here’s an image that shows an obstruction diagram, which the Starlink app on a smartphone … Continue reading Starlink – Part 11 – Obstruction Diagram
In part 3 and 4 of this Starlink discovery series, I’ve been taking a look and the downlink throughput performance. While the standard Cubic TCP congestion avoidance algorithm used by Linux produced only meager results, switching to BBR produced a five-fold throughput increase. So how about throughput in the uplink direction?
In part 3 of this series, I’ve taken a look Starlink’s downlink performance with the non-standard TCP BBR congestion avoidance algorithm. Overall, I was quite happy with the result as, despite the variable channel and quite some packet loss, BBR kept overall throughput quite high. Cubic, the standard TCP congestion avoidance algorithm, is not quite … Continue reading Starlink – Part 4 – Downlink Performance – Standard Cubic
After the more high level parts 1 and 2 on Starlink, it’s now time to have a closer look at how the Starlink downlink channel behaves. I’m totally amazed by the system and it performs very well in Germany. That being said, it probably comes as no surprise that on the IP layer, the graphs … Continue reading Starlink – Part 3 – Downlink Performance – The BBR Version
Summer seems to have taken a break in the second half of July, and the day I wanted to test Starlink at another place and demonstrate it to some people was as inhospitable as it could probably get during a summer day in Germany: The temperature was well below 20 degrees Celsius, it was very … Continue reading Starlink – Part 2 – Radio Shadow, Rain and Umbrellas
I’m sure you’ve seen the one or other satellite focused post on this blog over the last year. So far, I’ve mostly been looking into handheld satellite text messaging, but I always had a close eye on Starlink as well. Recently, Starlink has lowered their prices and introduced mobile tariffs that can be activated and … Continue reading Starlink – Part 1 – First Bring-Up
While heat insulating windows are a great thing, they have one big disadvantage: They also block RF signals. That means that cellular reception inside buildings and trains becomes very difficult. Back in 2016, I first heard about the concept of modifying the heat insulation layer of windows so they would let RF signals through. At … Continue reading Train Windows Permeable For Cellular Signals – From Theory to Practice
When flying in the simulator, I’m quite amazed how many radios a modern GA airplane or airliner has on board. Sometimes, it feels more like a flying radio tower than an airplane. The picture above and below shows the antennas of a Daher TBM 930 turbo-prop plane on its roof and its underside. Needless to … Continue reading Reality Bites – Flight Simulation – Part 8 – Radios In Planes
And again a seamless continuation from part 4 on 3GPP’s Non-Terrestrial Networks specification extension in Release 17 in which I’d like to come back to a particular requirement: The mobile device has to be aware of its location, which means it has to get a GPS fix before it can contact the network via a … Continue reading NTN – Part 5 – Why Does the UE Need a GPS Fix?
Wow, this is already part 12 in my blog series on the Garmin InReach Mini 2 and the underlying Iridium satellite constellation. Perhaps you remember, my main use case for the Mini 2 is to have a means to communicate with family members in other countries should there be a longer network outage, be it … Continue reading When All Else Fails – The Garmin InReach Mini 2 – Part 12 – Capacity for InReach