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SDR Colorgramme is a software designed for the detection and counting of meteors via radio echoes within the RF spectrum rather than the audio spectrum.

It is a dedicated program using PothosSDR, capable of controlling various SDR receivers such as:

After installing PothosSDR-2021.07.25-vc16-x64, you can verify that your hardware is recognized by opening a Windows DOS console and typing: SoapySDRUtil --probe

This documentation does not cover the installation of your SDR hardware; we assume it is already installed and has been tested using another software.

If this is not the case, we advise you to first install Gqrx SDR, which is cross-platform and highly effective at hardware recognition.

As a reference, SDR Colorgram was developed using an HB9CV antenna and a Nooelec NESDR SMArTee SDR dongle tuned to 143.05 MHz to monitor the Graves radar.

The software is configurable and designed to minimize the impact of interference such as the Graves carrier, aircraft, numerous satellites, and transient noise covering a wide frequency spectrum (such as lightning storms).

The detection principle is simple: it relies on a technique used in optical astronomy, namely the measurement of the Full Width at Half Maximum (FWHM), applied to an RF spectrum.

Detection is performed in real time, and the relevant RF spectrum curve is saved as an image in a "meteors_captures" subfolder.
An image of the "time zone" waterfall is also saved—with a delay—in a "waterfall_captures" subfolder.

The images in these two subfolders are organized by year/month/day, and the timestamp is included in the image filename.

The waterfall helps interpret the validity of the detection within the RF spectrum by contextualizing it within its temporal environment, is always recorded when the detected meteor is at the center of the image (y=100px).

Two additional parameters supplementing FWHM detection allow you to "filter" and prevent false detections:

These simple parameters give me great satisfaction on my setup, despite living under an air corridor, dealing with an extraordinarily high number of Starlink echoes, and facing the Graves radar shifting its frequency and phase more or less randomly.

In any case, it must be understood that 100% automatic detection is virtually impossible; you must accept "losing" a few echoes by giving yourself a safety margin on the settings, otherwise false detections will become too numerous.

This software can also be used on other frequencies, such as dedicated transmitters around 50 MHz or for observing AM transmitters.

It features an audio output filtered for comfortable listening. Naturally, you can simply mute the computer's sound or change the audio source if you prefer not to hear it.

Calibration is the only operation requiring supervision the first time you run the software.

Press the "Start" button to start the receiver; you will see the RF spectrum come to life along with the FFT waterfall below it.

An initial calibration will run over 200 lines (the height of the RF waterfall). This is entirely arbitrary, but generally sufficient for the software to "discover" at least the basic parameters—such as the Median FWHM—and set an initial FWHM Threshold accordingly. You can then fine-tune the FWHM Threshold and Detection Threshold settings.

Once the settings yield results that satisfy you best, click the "Save CONFIG" button. Your parameters are then saved. If you close the software or experience an unexpected power outage, your settings will be automatically restored without any action on your part.

Finally, if you wish to participate on www.rmob.org, you must fill out the form that opens when you click the "Observer" button.

Fill in all fields properly and submit. Normally, every 30 minutes, the software will transfer your data to the web server at www.rmob.org/live.php.
You will also find two files bearing your name in the root folder of the software:

ALL TIMES and DATE in images timestamp and RMOB file is in UTC AUTOMATICALLY calculated from your computer location zone, don’t change anything about date and time !

Overdense meteor, strong graves radar carrier and complex echo remanence
In this case SDR Colorgram have only one echo count !

Permission is hereby granted, free of charge, to any person obtaining a copy of this SDR Colorgramme and associated documentation files (the “SDR Colorgramme”), to deal in the SDR Colorgramme without restriction, including without limitation the rights to use, copy, distribute copies of the SDR Colorgramme, and to permit persons to whom the SDR Colorgramme is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the SDR Colorgramme.

THE SDR Colorgramme IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SDR Colorgramme OR THE USE OR OTHER DEALINGS IN THE SDR Colorgramme.