Search results for: meteor scatter

Techniques for using the RTL Dongle for Detecting Meteors

Back in 2013 we posted about a Dr. David Morgan who had written a tutorial paper discussing how he used the Funcube Dongle Pro+ for radio astronomy. Recently Dr Morgan has also written another paper showing how to use the RTL-SDR together with the Spectrum Lab software to detect meteors.

A software defined radio can be used to detect and count meteors entering the earth’s atmosphere by detecting strong radio waves reflected by ionized trails left by the meteor. If you are unfamiliar with how to detect meteors using radio waves, you should consult Dr Morgans older papers called Detection of Meteors by RADARMeteor Radar SDR Receiver (Funcube Dongle), and Antennas for Meteor Scatter. The tutorial shows how to set up SDR# and Spectrum Lab to work together to detect meteors using the Graves Radar in France at 143.050 MHz.

Meteor Scatter Detection in Spectrum Lab
Meteor Scatter Detection in Spectrum Lab

Detecting the Perseids Meteor Shower with an RTL-SDR Passive Radar

Amateur radio hobbyist EB3FRN has made a post on his blog showing how he was able to use an RTL-SDR to act as a passive radar and detect meteors from the Perseids meteor shower. To do this he tuned to 143.050 MHz which is the the frequency of the Graves radar, a French space surveillance radar used to spot satellites and detect their orbits. He then used the Baudline software to record the radar signal scatters which occur when a meteor reflects the Graves radar signal.

Graves Radar - 2013 Perseids Meteor Shower

Perseids Meteor Reflection Observations with the RTL-SDR

In this video YouTube user ek6rsc shows a timelapse of meteor reflection observations during the yearly Perseids meteor shower which occurred in 2013 during August 10-15. To do this he uses an R820T RTL-SDR tuned to 59.25 MHz, and the HROFFT software to do the recording.

Meteors entering the atmosphere can cause radio frequency reflections which may allow extremely distant radio signals to be received briefly. Reception of such a signal may be a good indicator that a meteor has fallen. A good informational guide on meteor scatter with the RTL-SDR can be found in this pdf file by Marcus Leech.

2013 Perseids Aug10-15 radio observations Meteor reflection 59.25Mhz

Meteor Reflection Observations with RTL-SDR

YouTube user ek6rsc has posted a video showing one week of meteor scatter observation at 59.25MHz using the rtl-sdr and the HROFFT software. More information about meteor scatter observations can be found at the page of The International Project For Radio Meteor Observation. The rtl-sdr is handy as a cheap monitoring tool for purposes such as this. From Wikipedia meteor scatter is described as follows.

 Meteor burst communications (MBC), also referred to as meteor scatter communications, is a radio propagation mode that exploits the ionized trails of meteors during atmospheric entry to establish brief communications paths between radio stations up to 2,250 kilometres (1,400 mi) apart.

The results of observations 1 week Meteor reflection 59.25Mhz

Starlink Doppler Reflections Caught with an RTL-SDR

Over on YouTube William IU2EFA has been uploading multiple short "meteor scatter" videos. This involves using an RTL-SDR to briefly receive distant radio stations via the RF signal reflecting off the ionized trail left by meteors entering the atmosphere. However, in a similar fashion satellites orbiting the earth can also reflect distant radio stations. 

In one of his latest videos William caught a train of Starlink satellites reflecting the signal from the Graves radar in France. To do this he uses a 10 element VHF Yagi, and an RTL-SDR running with HDSDR and SpectrumLab. In the video you can see and hear the change in frequency caused by the doppler shift.

Starlink is a SpaceX project aiming to bring ubiquitous satellite internet to the entire world. Currently 358 Starlink satellites are in orbit, and the end goal is to have 12000.

IU2EFA Starlink radar Graves doppler reflection

Starlink GRAVES Radar Reflections Received with SDR

Over on YouTube Jan de Jong who is based in Germany has posted a short slide show video showing that he received reflections of the GRAVES space radar from the new Starlink satellites.

Starlink is a SpaceX run satellite constellation that is slowly being launched in order to provide worldwide satellite internet access. The last launch was on 11 November 2019. Typically multiple satellites are launched at once, and they follow each other closely in a line, slowly spreading out.

The GRAVES space radar is a powerful radar based in France that is used to track satellites. If you are not too far away from France and within the GRAVES radar footprint you can point an antenna at the sky, and tune to the GRAVES radar frequency of 143.05 MHz with an RTL-SDR or any other SDR. You might then receive the reflections of this radar signal coming from satellites passing overhead. GRAVES has also been used for meteor scatter detection.

As the 60 and more satellites from Starlink 2 pass over the Graves radar signal they reflect a vertical track on the HROFFT radar image from the 143.05Mhz signal. In the first images the satellites are all still very close together, in current passes they have spread already and the display looks almost like rain in the sky on the 1 second radar plot from HROFFT.
Signal received with SDR RTL (SDRuno RSP1A) and 3 element Yagi at 45 degrees towards south

#Starlink-2 Passes over #Graves Radar #ElonMusk

WWV and WWVH Special Messages to Broadcast!

Starting from Monday September 16th and continuing through to October 1st, both WWV and WWVH shortwave time signal transmission stations will broadcast a special message from the Department of Defense to mark the centennial of WWV. These messages will be heard on 2.5, 5, 10, and 15 MHz. In addition from September 28 to October 2 a special WWV event will occur:

The world’s oldest radio station, WWV, turns 100 years on October 1, 2019, and we are celebrating!

From September 28 through October 2, 2019, the Northern Colorado ARC and WWV ARC, along with help from RMHam, FCCW, and operators from across the country, are planning 24-hour operations of special event station WW0WWV on CW, SSB and digital modes. Operations will shift between HF bands following normal propagation changes and will include 160m and 6m meteor scatter. We will be operating right at the WWV site and face a challenging RF environment.

WWV is a [NIST] operated HF station based in Fort Collins, Colorado. It continuously broadcasts a continuous Universal Coordinated Time signal in addition to occasional voice announcements. It has been on the air since 1919 but began continuous broadcasts in 1945 from it’s final site in Fort Collins, Colorado. WWVH is a similar time signal, but based in Hawaii.

The WWV Transmit Building

The WWV time signal can be used to automatically set RF enabled clocks to the correct time. [Andreas Spiess] on YouTube recently uploaded a video where he emulates this signal in order to control clocks within his home. This is a great watch if you’d like to learn more about how these time signals work.

The time format itself is actually pretty simple and it’s possible to emulate with a number of devices from an Arduino to Raspberry Pi and of course Software Defined Radio.

#287 Remote Controller for Clocks (IKEA and others, DCF77, WWVB, MSF, JJY)

New SDR# Plugin: Radio-Sky Spectrograph Data Stream

Edit: If you downloaded an older version of the plugin please note that it has now been updated. The update fixes some stability issues which would previously hang SDR#. The updated .dll file can be downloaded directly from https://goo.gl/0dPzOL.

Radio-Sky Spectrograph is a radio astronomy software program which is often used together with the RTL-SDR or other similar SDRs. It is best explained by the author:

Radio-Sky Spectrograph displays a waterfall spectrum. It is not so different from other programs that produce these displays except that it saves the spectra at a manageable data rate and provides channel widths that are consistent with many natural radio signal bandwidths. For terrestrial , solar flare, Jupiter decametric, or emission/absorption observations you might want to use RSS.

Usually to interface an RTL-SDR with Radio-Sky Specrtograph a program called RTL-Bridge is used. However, now SDR# plugin programmer Alan Duffy has created a new plugin that allows SDR# to interface with Radio-Sky Spectrograph via a network stream. This allows it to work with any SDR that is supported by SDR# plugins. Alan Duffy writes:

I wrote the plugin after becoming interested in amateur radio astronomy. The plugin allows you to use any of the software defined radios supported by SDR# to feed the Radio-Sky Spectrograph program with wide-band data. The plugin shows the frequency, bandwidth, and FFT resolution and has a user selected "Number of Channels" that are sent to the spectrograph program with an allowable range of 100 to 500. This number can only be edited when the data stream is not enabled. Also if certain key parameters change, such as the frequency or decimation, the network stream will stop as the spectrograph would no longer be capturing the same data. If this happens, simply click the start button on client side software (i.e. Radio-Sky Spectrograph). As long as the Enable box is checked on the server side, the plugin will listen for a connection and start transmitting data after RSS makes a new request for data.

We note that the software might also be useful for simply capturing a long term waterfall for finding active frequencies or looking for meteor scatter or aircraft scatter echoes. 

The Radio-Sky Spectrograph SDR# Plugin
The Radio-Sky Spectrograph SDR# Plugin