RTL-SDR for Satellite Weather on GOES16 – Planning

Introduction

In previous posts we looked at receiving weather information via HFWEFAX (Ref.1) and GRIB files (Ref.2) over an internet connection. In the next several posts, we will examine receiving weather information directly from a geostationary satellite GOES16(R) and see if it is suitable in a marine application for solo/family blue water sailors. My thanks to Yves_First42s7 for suggesting this topic.

Geostationary Weather Satellites

CountrySatellite NameLongitude
United StatesGOES16(R)
Atlantic Ocean
75.2degW
GOES17
Pacific Ocean
137.2degW
RussiaElectro-L No.1
Indian Ocean
76degE
JapanMTSAT-2
Himawari
Pacific Ocean
145degE
140degE
EuropeMeteosat 6/7/8/963degE, 57.5degE
3.5degW, 0degW
ChinaFengyun FY-2E/2F/2G/4A86.5degE, 123.5degE
105degE, 104.5degE
IndiaINSAT 11 operational74degE – 93.5degE
Table 1 Geostationary Weather Satellites (Ref.3)
GOES16(R) Signal & FreqSignal Parameters
GRB Rebroadcast
1686.6MHz
L Band
Dual Circular Polarization
QPSK DVB-S2 @ 8.665938Msps
15.5Mbps Coder Opt
60.5dBmi at Sat edge footprint
9/10 rate + BCH coding
SRRC filter alpha=0.25
NRZ-L baseband coding
10.9MHz BW
VSAT antenna size 4.5m
HRIT/EMWIN
1694.1MHz
L Band
Vertical Polarization with offset
BPSK @ 927Ksps/400Kbps
??dBmi at Sat edge footprint
Convolution/RS coding
SRRC filter alpha=0.3
BW=0.927*1.3=1.205MHz
VSAT antenna size 1m
Table 2 GOES16(R) Signal Parameters (Ref.5)
Fig.1 GOES16(R) Footprint (Ref.4)

Table 1 is a brief summary of geostationary weather satellites now in orbit according to Ref.3. In this post we will focus on GOES16(R) since it covers a good portion of the Western Hemisphere and is very well documented. Figure 1 shows the GOES16(R) footprint.

GOES16 Propagation Path

Fig.2 Propagation Diagram Observer Same Longitude as Geo Satellite

Figure 2 shows the propagation geometry for an observer located on the same longitude as a geostationary satellite. Distance dcgeo is the distance from the centre of the earth to the satellite located above the equator. Distance dogeo is the propagation distance between the observer and the satellite and Hc is the elevation angle and Lfs is the free space loss in dB. Sample calculations for Toronto, Canada:

Observer Latitude = 43.71degN Longitude = 79.40degW
dogeo = 37816Km Hc = 39.6deg
Lfs = 32.44 + 20*log10(1694.1_MHz) + 20*log10(37816_KM) = 189dB

Fig.3 Propagation Drawing Observer Different Longitude than GeoSatellite
Fig.4 ScicosLab GeoSat Planner

Figure 3 shows the propagation geometry where the observer is on a different longitude than the geostationary satellite. Figure 4 shows the ScicosLab solution for Toronto, Canada to GOES16(R) at 75.2degW. Satellite EIRP of 60dBmi (?? same as DRB) for an HRIT signal. Sample calculations for Toronto, Canada:

Observer Latitude = 43.71degN Longitude = 79.40degW
dogeo = 37830Km Hc = 39.4deg Bearing = 174deg
Rx LNA gain = Gramp =30dB
Rx Ant gain = Grant = 15dB
Grx = Gramp + Grant = 45dB
Lfs = 32.44 + 20*log10(1694.1_MHz) + 20*log10(37830_KM) = 189dB
Pr = Pt + Gt + Gr -Lt – Lr – Lfs = 60dBm + 45 -189 = -84dBm
Pn = Fa + 10*log(BW_Hz) – 174 dBm = 3 + 10*log(1,205,000) – 174 = -110dBm
SNR = 26dB

Fig.5 Rx Location to CN Tower Toronto Canada
Fig.6 Rx Location Balcony View CN Tower

Figure 5 shows the azimuth from the Rx location to the CN tower which is 171deg, Figure 6 shows the lucky view from the Rx location showing the CN tower in the middle and about 5deg clearance to both East and West.

Reception Preparation

In order to receive the GOES16(R) signal, rather than piecing components together, I purchased a kit of components from NooElec that was specifically designed for that purpose. Lucas Teske in Brazil (Ref.6) has an excellent video that goes into great detail on how to assemble the package and acquire a signal. Before assembling the antenna, I did some preliminary tests using a Signal Hound spectrum analyzer with/without the SAW+LNA module using a simple vertical that was supplied with my original RTL. Figure 7 shows the spectrum around 1.694GHz without the SAW/LNA module and Figure 8 shows the spectrum with the module. Note the gain and approx. 80MHz bandwidth.

FIg.7 SignalHound Spectrum Analyzer with Whip Antenna
Fig.8 SignalHound with SAWBird+ Module with Whip Antenna
Fig.9 YouTube Video RTL-SDR for Satellite Weather on GOES16 – Planning

Please send your comments, questions and suggestions to:
jclark@clarktelecommunications.com

YouTube Channel
YouTube Channel

References

#1. – “RTL-SDR for Marine HF Weather Fax”
https://jeremyclark.ca/wp/telecom/rtl-sdr-for-marine-hf-weather-fax/

#2. – “Open Plotter – GRIB Files”
https://jeremyclark.ca/wp/telecom/openplotter-grib-files/

#3. – “Weather Satellite”
https://en.wikipedia.org/wiki/Weather_satellite

#4. – “NOAA GOES16 Footprint “
https://www.ospo.noaa.gov/Organization/FAQ/footprint.html

#5. – “GOES-R Series Specifications”
https://noaasis.noaa.gov/GOES/about_goes-r_series.html

#6. – “Review of NooElec GOES Kit”, Lucas Teske
https://www.youtube.com/watch?v=QqSAa2ociLI

By Jeremy Clark

Jeremy Clark is a Senior Telecommunications Engineer and Advanced Amateur Radio Operator VE3PKC. He is the author of E-Books on Telecommunications, Navigation & Electronics.