Monthly Archives: October 2017

GOES GRB First Light!

When the GOES-16 was first announced I got interested in their GRB Downlink (although the first try was at HRIT downlink). Basically GRB is a replacement for the old PDR downlink in GOES 13/14/15 generation, which gives few advantages over the old link:

  • Uses market standard DVB-S2 Generic Stream
  • Have FEC (as defined by DVB-S2)
  • Higher bandwidth
  • Easier to receive due DVB-S2 FEC

For those who don’t know, the GRB is a direct rebroadcast of GOES data, with minimum processing as possible (usually just packaged into NetCDF files with calibration parameters) and is intended for anyone that want’s to get full data from the satellite.

The down-link itself is split into two channels transmitted at same frequency (1684.5 MHz) with different circular polarities. That makes extremely necessary to use Circular Polarized feeds, since a Linear Feed will suffer with cross polarization (sum of each channel at the same signal).

For HRIT downlink usually a 1 meter dish is enough for receiving with a good signal (needs a very good hardware setup though). But for GRB, the minimum dish size listed by NOAA is 3.8m for the best regions.

GRB Recommended Dish Size by NOAA

Continue reading