So with some fine weather at the beginning of the week I finally got round to installing the turnstile antenna for NOAA weather satellite reception. Took far too long as I had a very dodgy piece of coax. The antenna sits on the top of the mast holding my Cobweb antenna. Routing the cables fairly discreetly means it’s about a 30m run and I had a length of cable just perfect. However despite both inner and outer continuity both ends, and working fine when tested with a dummy load the cable had an issue when feeding the antenna. Signals were far too low and the swr curve did not look right at all. Search me why though…..

So that cable was binned and I ended up using about 3x10m lengths of RG213. Anyway……results were fine but it was interesting to note that at some positions of a pass the V2000 at 3m height had an advantage over the turnstile at 7/8m high. They are separated by around 10m and obviously have different views of the sky and the blocking objects such as trees, building etc. Overall I would say the turnstile has a slight advantage though if you can only use a low vertical co-linear then you’ll be doing just fine and not missing much.

Here’s an example of a pass using the turnstile twig.

I’ve started uploading decoded satellite images directly to a dedicated website. The pc version of wxtoimg supports this very well – automatically decoding and ftp’ing images after each pass using a supplied html template. If I could find a way for the Raspberry Pi command line version to do this we’d be quids in…Here’s the dedicated website: Weather Satellite Images

So I noted yesterday that the MCIR with Precipitation image enhancement was not “with precipitation” as there was no colour. It was imply MCIR enhancement. Now wxtoimg comes in three flavours: Standard, Standard registered and Professional. Back in the day I had paid for a Professional key and I had entered that into my PC version and all was fine. Incidentally Standard and Professional keys are freely available on https://wxtoimgrestored.xyz/downloads/. Seems like the author of wxtoimg has lost interest in it and abandoned the project and is happy for the keys to be in the public domain.

Now the MCIR with precipitation enhancement is only available in the professional version. So how to enter the unlock key into my command line Raspberry Pi wxtoimg version?

I have not seen the following information reported before. To get the professional version running on the Pi here are the steps.

Firstly you need to log into the Pi via a graphical interface. I use VNC Viewer on the PC. If you are running your Pi headless like me (i.e. normally using a terminal to log in, putty in my case) you will get the message “Can not display desktop”. The solution is to either plug a hdml cable into the Pi (doesn’t have to be connected to a monitor) or, more elegantly, to use raspi-config to change the default low resolution to the highest you are offered.

Once you are logged in you have to launch wxtoimg in graphical mode by either running “wxtoimg -G” or xwxtoimg. You can then click “help/enter upgrade key” and your standard unregistered copy become a professional version with all enhancements unlocked. But…………………………………… After you log out and close the program down when you restart it the registration details have disappeared and it has reverted back to the unregistered standard version. The answer is to run “sudo wxtoming -G” and enter the relevant credentials. But there is another but………………….Subsequently you always have to use sudo to launch the program or else you are running the unregistered version…………wtf!

So in the scripts which launch wxtomimg to decode the passes on the Pi I have prefaced the wxtoing calls with sudo, e.g.

sudo /usr/local/bin/wxtoimg -m ${3}-map.png -c -e MCIR-precip $3.wav $3.MCIR-precip.png

And finally you really can get the MCIR with precipitation enhancement!!! See below for a couple from this morning:

Well what a faf de klerk! Still we got there in the end.

With regard to the Pi images seeming cleaner I think this may be to do with the Pi recording the pass at 60 kHz bandwidth (the value in the script I copied) whereas on the PC I was setting bandwidth to 34 kHz.