Friday, August 28, 2020

Weather Sats (again)

So, I've been playing around with my SDRPlay RSP1 on an rpi4, which has enough power to run a GUI SDR++.

One application was to receive NOAA APT files, decode, and display WX pictures.
The current functioning APT satellites are NOAA 15, 18 and 19, and folks get decent
images using modest antennas.

Mostly.

Not so me, at least with that setup. I have an MFJ 2m/70cm groundplane on the corner of my roof at about 3 meters and it's, eh, ok. Not great.  Plus with my neighbors house, our house, and trees around, you really need decent passes for decode anyways, but the ground plane really has some nulls on high passes, which is frustrating with the obstructions on low passes.

That said, I'll eventually get around to building a more suitable WX Sat antenna, several plans are out there.

For now, though, I really have not cracked the code between CubicSDR and any of the APT decode programs... noaa-apt seems most acceptable, but the GUI version doesn't seem to have options to decode all the various filtered images available from the download data stream, unlike wxtoimg, which apparently has the filters coded in, but for the life of me, can't seem to work with CubicSDR's data.

So, I went simple and reconnected my rtl_sdr dongle with an FM broadcast notch filter.

A straight pull of raspberry-noaa, which is a nice git repository which has pulled all the rtlsdr scripts in an easy to use "plug and play" solution.

https://github.com/reynico/raspberry-noaa/blob/master/INSTALL.md

it was literally 5 steps:

cd $HOME
git clone https://github.com/reynico/raspberry-noaa.git
cd raspberry-noaa
./install.sh

and then change some directory permissions to allow the scripts to create the image/audio directories.

Let it run.

Not perfect images by any stretch, but a lot better than the other attempts I've been doing.

Results are back to what I used to get, and about expected with my location and given antenna performance