As a kid, when we visited the planetarium in Stuttgart, I always was amazed about the monitor in the waiting area where they displayed the current weather satellite images they were able to receive. The setup really was impressive, with a special antenna outside of the planetarium and lots of hardware receivers and amplifiers that decoded the MeteoSAT signals. While it was impressive, it always was clear that all the hardware required was simply too expensive for a student to buy and install. Since then, I almost forgot about the fascination of receiving satellite signals with my own groundstation.
But that fever came back last year, when I saw a presentation during 34c3 about SatNOGS - a project for a crowd-sourced network of satellite groundstation spanning all over the world. So I knew, I wanted to be part of this network and add my own groundstation to this initiative.
Six months ago, I installed my SatNOGS groundstation. And since then, the station was able to record more than 1300 observations, most of them with a vetting result of „good“.
During the first weeks, I found that the signal-to-noise ratio (SNR) was quite low, so in order to improve quality, I installed a low-noise amplifier (LNA). This only took a few minutes but really improved quality of reception. With the new hardware setup, I was able to receive e.g. good quality images of NOAA satellites or FM radio from the ISS. The fascination I already had as a kid is back!
With this easy installation, I think everyone who is interested in receiving and decoding satellite signals should be able to setup their own SatNOGS groundstation and „donate“ reception capabilities to the global network.
Over on their wiki page, SatNOGS is providing great installation instructions - their reference design just uses a Raspberry Pi 3 with a RTL-SDR (software defined radio) and an omni-directional antenna.
To make it easier to follow the reference setup, this is my list of materials I used for my setup:
- Antenna: TA-1 Turnstile Kreuzdipol 137-152 MHz with N-Kabelbuchse RG-58 from wimo.com
- Computer: Raspberry Pi 3 Model B, with standard housing
- RTL-SDR: Nooelec NESDR smart-premium RTL-SDR
- LNA: „Wideband LNA with FM notch filter Low noise RTL SDR Airband USB“ e.g. from ebay (USB was important to me so the LNA could be powered by one of the USB ports of the Raspberry)
- Weather Box: weather proof box from ARLI (20x30x13cm) e.g. from Amazon
- Antenna-Connection / Box entrance: SMA Male to N-Type Male Flange 4 Hole Panel Mount Kabel Connector , e.g. from ebay
- Cable connection between LNA and RTL-SDR: 20CM Length SMA Male to SMA Male Connector Pigtail Cable Wire GAB , e.g. from ebay
- USB Connection from Raspberry to LNA: short standard Micro USB Cable
- Power Supply for Raspberry: As I am powering the Raspberry via Power-over-Ethernet, I am using a POE splitter with Micro USB connector, e.g from ebay. This way, I just need one Ethernet Cable running from my POE Switch to the Weather Box - no additional power cord necessary.
After building up the antenna it looked like this:
In the weather box, installation looks like this:
Next iteration of improvement might be the installation of a DHT22 inside the weather box to control temperature and humidity inside the box.