National Weather Service United States Department of Commerce

Damaging High Winds and Critical Fire Weather Threats in California

A strong low pressure center off the southern California Coast will produce high winds in the Sierra-Nevada mountains, and central and southern coastal ranges. Very dry conditions combined with these high winds will produce critical fire weather threats in the central and southern coastal ranges. Heavy snow in the South and Central Rockies, and Great Lakes; and heavy rain in Hawaii will continue. Read More >

HRIT/EMWIN Reception


Sources for HRIT/EMWIN systems and components:


US Government auction of L-band frequency spectrum (1695 to 1710 MHz) adjacent to GOES-R HRIT/EMWIN transponder frequency is likely to adversely impact the reliability of HRIT/EMWIN signal reception in the US due to cell phone interference.

 

HRIT/EMWIN Downlink Characteristics (NESDIS-2)


Coding – BPSK

  • Convolutional rate ½ code with constraint length 7 concatenated with Reed Solomon (255,223) with Interleave = 4
  • Square Root Raised Cosine filtering using an Alpha factor of 0.3
  • The resulting “Necessary Bandwidth” for this signal will be 1.205 MHz

Modem Required: predicted C/No is in the range of 63-67 dB
Maximum Demodulator Required is -

  • Eb/No is 4.6 dB for a BER of 1x10-8 after decoding

Minimum Antenna System

  • At 5 degree elevation, the minimum antenna is 1.2 meter.
  • At 10 degrees or more elevation the minimum size is 1.0 meter
  • Using a LNA or LNB with a system noise temperature of about 200 K will provide a G/T of 1.0 dB/K or -0.3 dB/K respectively