Echoes: An RTL-SDR Tool for Meteor Scatter Detection

Echoes Running
Echoes Running

Thanks to "gmbertani" for letting us know about his recently released RTL-SDR compatible software called "Echoes". Echoes is a Windows, Linux and Raspberry Pi/Arch compatible tool that can be used together with an RTL-SDR and appropriate antenna to monitor for meteor scatter detections.

Meteor scatter works by receiving a distant but powerful transmitter via signal reflections off the trails of ionized air that meteors leave behind when they enter the atmosphere. Normally the transmitter would be too far away to receive, but if its able to bounce off the ionized trail in the sky it can reach far over the horizon to your receiver. Typically powerful broadcast FM radio stations, analog TV, and radar signals at around 140 MHz are used. By listening to these signal blips it can be possible to estimate the number of meteors falling.

Below we paste the official description and feature list of Echoes, and at the end is a video demonstrating Echoes in action:

Echoes it's a radio spectral analysis software for RTL-SDR devices, designed for meteor scattering purposes.

Echoes doesn't demodulate neither decode any human-made signal. Its main goal is to analyze and record the total power of natural signals and generate screenshots and tabular data (CSV, GNUplot) output in presence of particular peaks in a selected narrow range of frequencies. Since there is no demodulation, there is no provision for audio listening, except for a notify sound when an event has been recorded.

Features

  • Captures waterfall spectra as PNG screenshots and statistics data files.
  • Optionally generates GNUplot data files
  • Multiple instances can manage separate dongles plugged in the same computer
  • Three operating modes: continuos (records data only), periodic (captures data and screenshot every X seconds) and automatic (record data and screeshot each time a customizable (S-N) treshold is exceeded)
  • HTML report production
  • Installers ready for Windows7++ and RPMs / SRPMs for Linux
  • xz binary package for Raspberry PI / Arch distro
  • It can run headless, recording GNUplot and statistic data only

perseidi 2017

15 comments

  1. Giuseppe Massimo Bertani

    Hi Max,

    I introduced the periodic mode because it’s the simplest and dumbest way to take screenshots. Simplest because it does not need to set signal thresholds (automatic mode) and dumbest because in this way you record a big amount of data that must be manually selected afterwards. This is also a way to learn about how to set the thresholds for automatic mode.
    The “shot x sec after peaks” control (manual fig.8) does exactly what you’re thinking. The best value should be equal to the time coverage of the waterfall minus 1..2.
    The time coverage depends on the “time interval” control (see manual fig.7). Increasing this value, the waterfall slows down.
    Don’t take in count the “shot duration” control, because it is not about screenshots but about the plot data files.

    Thanks for your feedback.

    Massimo

  2. Giuseppe Massimo Bertani

    Hi Max,
    I introduced the periodic mode because it’s the simplest and dumbest way to take screenshots. Simplest because it does not need to set signal thresholds (automatic mode) and dumbest because in this way you record a big amount of data that must be manually selected afterwards. This is also a way to get an idea about how to set the thresholds for automatic mode.
    So, the delay you mean – “shot x secs after peaks” (see manual 6.3.4) – must be exactly what you’re asking for. Its best value is equal to the total waterfall coverage in seconds, minus 1..2. Notice that you can increase the refresh interval (6.3.3) to make the waterfall browsing slower.
    Remember, the “shot duration” is meaningful only when you record plot files, not screenshots. If you don’t plan to use GNUplot, forget about it.
    Thanks for your feedback.
    BTW. in future, it’s better mail me directly since I get no notifications if someone writes a comment here. Today I’ve seen your post and the post above almost casually, since I didn’t know yet about the article 🙂

  3. Anonymous

    I am a newbie with SDR, so not sure I fully understand how this ECHOES works.
    Does it mean that it only receives reflected waves from GRAVE radar that transmits the waves?
    So it receives the waves at the same frequency as the GRAVE radar transmits?
    Thank you for for explanation

    • Giuseppe Massimo Bertani

      Hi,
      no no, Echoes can be tuned on any frequency supported by your dongle, it’s not GRAVES-centric. The examples in the manual use the GRAVES because in Europe it’s the best source of radar signals for meteor scattering purposes, since it works 24h (except in maintenance stops).
      You should find something similar source located at about 1000…3000 km from your site (looking at the hour you wrote your message, it seems you’re somewhere in America) it could be also an analog TV station – if they still exist there – working in VHF bands I..III . Some says that frequencies below 80MHz give the best results, but I only heard about, never checked.
      If you contact a radio-amateur club I think they can give you much more help in setting up your station. There is also much material available online.
      Thanks for you feedback
      Massimo

  4. Max

    Regarding the 3 operating modes, i don’t think the periodic one is usable because reflecttions can last from less than 1 sec to more than 20sec but most of them are about 1 sec. only. I would like to understand what is the delay in automatic mode before it starts recording to make sure that very short reflections are not cut significantly at the beginning. However the automatic mode is interesting for particular times of the year with high number of reflections most of them lasting over 2 sec. like the Perseids in August

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