Ku band through an LNB
DVB-S2 satellite television
A satellite transponder read off a dish and LNB, QPSK to 32APSK with the symbol rate measured, down to the services on it and the picture and sound of the one you pick.
A universal LNB turns the Ku band into 950 to 2150 MHz on the coax, which a HackRF or a LimeSDR can tune directly. WaveShark finds the carrier within its channel, measures the symbol rate rather than asking for it, locks through the headers even when it acquired off frequency, and reads the frames down to the transport stream, with the LDPC decoder, demapper and spur cancellation vectorised to keep up.
On a HackRF that is a 14.25 Msym/s contribution feed read in real time; on a LimeSDR at 61.44 MS/s it is a 23 Msym/s multiplex, two neighbouring transponders at once. The radio’s own spur at the centre of the span is cancelled rather than left to wreck the lock. A carrier too weak to read is still shown rather than silently missing.
The satellite pointing window gives azimuth, elevation and LNB skew for any geostationary satellite from your station, with a level to peak the dish on. Programmes land in the same table as DVB-T, with now and next and scrambling marked.
What comes out
- Modulation and code rate, QPSK to 32APSK
- Symbol rate, measured, and roll-off
- MER, and frames that failed LDPC
- The services on the transponder, and now and next
- The chosen service, playing, with its sound
Pictures and sound need ffmpeg: the macOS download and a source build show them, the others list the services. Scrambled services stay scrambled.
$ waveshark --tune 1431.1 --span 20000 --videoRead next
Something did not decode?
Record the burst with --record and open an issue with the capture. A capture that decodes becomes a test fixture.
Open an issue