In our previous blogpost, we talked about ways to measure and compare antennas. If you haven’t read it yet, you should probably do so, unless you already know what antenna gain and VSWR are. Also, I want to reference the great Application Note AN-00501 again, which contains a lot of resources that help interpreting the following results.
Today, we’ll take a look at the results we got from antenna measurements. Since I already had a few LoRa antennas from various sources, I wanted to know how they compare. The best way to do that is with an antenna test chamber. Luckily, the people at the Institute for Communication Systems (ICOM) at HSR built themselves such a test chamber from an old SBB freight container. Continue reading
Over the last year, I started playing around with LoRaWAN, a long-range low-power wireless data transfer protocol. We internally crowdfunded a LoRaWAN gateway at Coredump and joined the Things Network. More about our gateway in a future blogpost. For a general introduction into LoRaWAN, I recommend watching this video. And this 33c3 talk is a fantastic introduction to the LoRa PHY layer.
This blogpost is not about LoRa or LoRaWAN itself though, but about a related topic: Antennas! In Europe, LoRaWAN is operated at a frequency of 868 MHz. After testing multiple antennas for LoRaWAN nodes and gateways, I wondered how these antennas can be compared. We’ll take a look at three metrics to compare antennas: Directivity, Gain and VSWR. And then – in a follow-up blogpost – I’ll present the results from a lab test of 11 different 868 MHz antennas. Continue reading