Receive full disk images from the NOAA GOES Network.
From my location in Seattle, WA, USA I'm specifically trying to catch signals from GOES-15 and GOES-17.
- Nooelec SAWBird+ Filter/LNA
- 50-4000MHz LNA (2x available)
- Altelix 2.4GHz Antenna. NOTE: The antenna has been modified to extend the forward reflector as noted in this reddit post.
- NooElec SMArTee XTR SDR
- Raspberry Pi 3
- SDR Sharp: Used for inspection of waterfall on windows.
- GOESTools from pietrn: A suite of software for receive and processing of GOES signals.
- A minimal LRIT/HRIT reciever - From the
goestoolsproject page. - 2.4GHz Antenna Mod
- See README.md for additional links.
My general hardware setup is as follows:
Antenna --> SawBIRD+ Filter/LNA --> LNA --> SMAarTee XTR SRD
I had first attempted to connect the SDR directly to the RaspberryPi for processing using goesrecv (part of the goestools suite).
However, from my location in Seattle, Washington, USA, I was consistently getting Viterbi values of ~2000, which indicates no signal according to the goestools tutorial.
In an attempt to simplify my problem space, I removed goestools and the Pi from my setup, and directly connected the SDR to my laptop. From there I could visualize the signal waterfall using SDR#.
My understanding from the GOES Documentation is that the following frequencies are used to broadcast data from the GOES network:
- LRIT: 1691.0 MHz
- HRIT: 1694.1 MHz
- EMWIN (GOES-15): 1692.7 MHz
Using the waterfall display, I scanned each of these frequencies while positioning the antenna towards GOES-15 and GOES-17. I also re-oriented the antenna for horizontal/vertical polarization.
I was unable to see any discernible signal for the LRIT and HRIT data (which was backed up by the ~2000 Viterbi values using goesrecv).
However, I was able to detect what I assume is the EMWIN signal for GOES-15 at 1692.7 MHz (See Image Below).
Outstanding Questions:
- Is the signal I am seeing in the SRD Sharp waterfall actually the GOES-15 EMWIN signal?
- Is my high Viterbi value when using
goesrecvcaused by poor signal strength?- If so, what can be done to increase signal strength?
- If not, why am I receiving what I believe to be an EMWIN signal from GOES 15?
Additionally, I've tried a few different combinations of connectors. The antenna has a Type-N connector, and all of the other hardware uses SMA connectors. I originally was connecting the connecting the antenna to the SawBIRD+ using a BNC cable, with a Type-N adapter on one end, and an SMA adapter on the other.
In this experiment, I used the above BNC cable, and also tried attaching a Type-N to SMA adaptor directly to the antenna, which allowed me to use SMA jumper cable to connect all hardware. Both configurations yielded the same results.