SkyNet 5B Beacon on 7495,800 MHz
Typical PSK traffic on SkyNet 5B.
What can be found on the X-Band?
There is a lot of interesting traffic that can be found on the X-Band. I will be covering the military band (7.2 GHz – 7.8 GHz) and the DSN (Deep Space Network) band on this website. Next to all the military traffic you can find a few weather satellites and some other random satellites operating in that band. In general there is a lot of interesting traffic, including exotic waveforms (lots of PSK stuff) and some UHF -> X-Band relays. And the best thing – it changes regularly!
What hardware do I need to receive X-Band signals?
Here is a brief summary of the components you will need:
- a frequency downconverter consisting of a local oscillator (LO), a frequency mixer and an IF amplifier
- a good front end LNA (low noise amplifier) with a low noise figure
- a waveguide antenna for 7 – 8 GHz
- a big enough satellite dish
- a bandpass filter for the frequencies of interest
- high quality low-loss coaxial feeder for the high frequency part
I will now describe every bit of this list in detail down below.
1. The frequency Downconverter
The frequency downconverter is the most complex part to understand in this system. It basically consists of a frequency mixer and a local oscillator (IF amp will be covered later). So why does a local oscillator connected to a frequency mixer convert the frequency down? Have a look at this image: