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ha7ilm / openwebrx

Open source, multi-user SDR receiver software with a web interface
https://sdr.hu/openwebrx
GNU Affero General Public License v3.0
989 stars 476 forks source link

Improved waterfall display #49

Closed tejeez closed 7 years ago

tejeez commented 7 years ago

I found it was difficult to see weak signals in waterfall display of openwebrx. This could be improved by using slightly overlapping FFT windows and averaging power from multiple FFTs for each waterfall line. This helps improve sensitivity of the waterfall especially when using a high sampling rate and a relatively low fft_fps. Additionally, I changed the default waterfall palette to try to further improve its contrast and make weak signals easier to see.

I've also created a pull request to csdr to implement these averaged FFTs.

tejeez commented 7 years ago

BTW, if you quickly want to see what it looks like, it's in use at http://prk-12.prk.tky.fi:8073/ and http://sdr.dy.fi/

ha7ilm commented 7 years ago

@tejeez Wow, great!

leastonce commented 7 years ago

Great enhancement. I put this on my RPi today and it makes it a lot easier to see interesting signals.

Sent from my iPhone

On 23 Oct 2016, at 07:37, András Retzler notifications@github.com wrote:

@tejeez Wow, great!

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ha7ilm commented 7 years ago

@tejeez Thank you for your contribution! The waterfall looks much better now. I made some related, small changes:

816f860de38fb3a482dfaee6d2ccd86082060bea a31d4b9fe25fb14d9bf53afbaf3d0782539a81e7 943fa47a1c73d8bf911d6d908c8665ba40a4d816 1d19b07833e63761a507bcb73e9c56f081c751a4

What should still be evaluated if the new default colors work well with receivers that have higher dynamic range (e.g. 16 bit A/D). I'll try that later.

tejeez commented 7 years ago

Nice, thanks for interest in my contributions! I'm now working on more features to improve performance of my direct sampling receiver and I might contribute them soon as well.

The colors could probably still be improved. One could even take a look at the colors used in some other SDR programs (like linrad or gqrx) and try to mimic them in openwebrx. Would it be possible to choose the theme in the web UI?

ha7ilm commented 7 years ago

It should possible to do. The colors come down to an array in Javascript, that could be changed during runtime.