Setting up a ground station for satellite communications is a project that has been on my mind for a time, so I’m looking out for some advice. I would, however, welcome any guidance or recommendations from this informed community as I’m working with minimal resources.
My Present Configuration:
Antenna: I may install my simple Yagi antenna on my rooftop. Because it isn’t motorised, adjustments must be made by hand.
Radio: On my laptop, I have an SDR (Software Defined Radio) setup that includes a USB dongle and some simple software. I’ve tried decoding a few NOAA signals and am currently using GQRX for reception.
Location: Although I live in a suburban location with some RF noise, my rooftop provides a clear view of the sky.
Objectives:
Getting Satellite Data: My first objective is to be able to consistently receive data from CubeSats, weather satellites, and maybe even ISS transmissions.
Decoding Signals: I’d like to get better at decoding signals, particularly telemetry data. Although I’ve had some success with APT photos, I want to try this with other signals as well.
Extending Setup: I need to stay within my budget for the time being, but in the future, I’d like to automate the antenna tracking procedure and upgrade my equipment.
Enquiries:
Advice on Antennas: Are there any do-it-yourself projects or inexpensive additions I might do to enhance the functionality of my antenna?
Software Suggestions: In addition to GQRX, what other programs would you suggest using to decode other satellite signals?
Management of Resources: Taking into account my restrictions, how may I maximise the performance of my present setup?
As our initiative moves further, I can’t wait to learn new things and give back to the community. Any guidance, recommendations, or snowflake materials you could provide would be really valued.
These questions regarding antennas, rotators, filters and whatnot is asked and answered a lot in previous threads here. It is a recommended read.
A short 2-5 el yagi pointing straight up is a pretty good start. Preamp at the antenna.
Filters if there’s a lot of strong interference out of band, these can be placed in front of the SDR most of the time.
Regarding software, you are mentioning manual processes. GQRX is a versatile tool to see what is going on and selecting something interesting. If you want to process something further you need to get the samples out from that and into another program, audio looping is one method and UDP audio is another.
Another nifty program is SatDump, it has a lot more demodulation and processing built in, but it is not aimed at “listening around on the bands” so much.
For demodulating cubesats, I’d recommend gr-satellites but that needs to be fed from a receiver (gqrx, cli, flowgraphs, recordings).
There are many different aspects to cubesats. My advice is to start the journey with a simple installation and see what you like and don’t like……then go from there.
The simplest installation is to build a simple SatNOGS station for UHF a turnstyle antenna, a simple LNA with DC BiasTee feed, a RTL-SDR and a Rpi….a Rpi 4 or RPi3B+ both work fine. I use ATA Turnstiles. They are easy to build and work very well. I mount the LNA and a filter if needed, in a bit of PVC up near the antenna. That setup is minimal cost….no rotators or tricky yagis. You can add an auto-scheduler to get 200+ passes a day. Plenty of data to look at.
The second thing I would do is get a second SDR with a LNA for experimenting with. Use that with your laptop. You can make simple antennas to experiment with higher gain. For software start with simple packages like Gpredict and GQRX (or what ever package you prefer)……Once you can reliably track and receive satellites with that setup, you can then move on to decoders using GNURadio, gr-satellites and other packages.
That will give you a good feel for what you can do, which way you want to go and it is all pretty cheap….two SDR’s and a Rpi…plus some RF bits….
If you get hooked like most of us, you will end up with a continual job of learning and improving your setup.
Good questions, and you have already received some great answers. An RTL-SDR is a great start, but make sure you buy a reasonably decent one. Nooelec or RTL-SDR.COM brand is a good bet. That said, I would absolutely NOT skimp on putting an FM Broadcast Band filter in front of that SDR. Nooelec makes one called the Flamingo which is good, but the GPIO Labs filter is about 10dB more attenuation for not much more: FM Notch Filter 88-108MHz; Excellent Rejection 85dB; SMA-M + SMA-F Con – GPIO LABS
Also, the advice on pointing the yagi straight up is good. I did that for quite some time, and while I did not get much out to the horizon, I had about 50% of my passes with something copied.
in advance.