Category: Satellite

Meteor-M N2-2 Weather Satellite Updates: No More 137 MHz LRPT, L/X-Band Working in Daylight

In late December 2019 we posted about Russian weather satellite Meteor M N2-2 which had unfortunately been struck by a micro-meteorite on Dec 18, causing it to lose control and go offline. Meteor M N2 and N2-2 satellites are often monitored with RTL-SDR dongles as it is relatively simple to receive their LRPT signal at 137 MHz which contains a high resolution weather satellite image.

Recently Happysat updated his Meteor M status page, noting that Meteor M N2-2 has been partially recovered, but due to low power it can no longer transmit a 137 MHz LRPT signal ever again. However, the L and X-bands are transmitting while the satellite is in daylight. Happysat writes:

January 2020 There will be only short-term power-ups in the radio visibility zone, and the battery life will be reduced tenfold.

Of particular concern are the batteries they are very quickly overheated and switching from regular to backup.

Unfortunately the power supply features do not allow the 137 MHz transmitter to be used in abnormal power, mode (from solar panels) which is used now although technically it is working fine.

There will be no LRPT Transmission's anymore.

The older Meteor M N2 satellite remains operational transmitting at 137.100 MHz.

The Meteor-M2 Satellite
The Meteor-M N2 Satellite

Increasing L-Band Active Patch SNR by using it as a Feed for a Satellite Dish

Recently RTL-SDR.COM reader Bert has been experimenting with our active L-band patch antenna product. He's written in to share that he's found that using it as a feed for a satellite dish works well to improve SNR on those weaker 10500 AERO signals which Bert found that he could not decode from his location due to insufficient SNR. Our active L-band patch antenna receives signals from 1525 - 1637 MHz and can be used for signals from Inmarsat, Iridium and GPS satellites.

To use the patch as a feed Bert used a 40mm drain pipe and mounted the antenna on the end of the pipe. The drain pipe fits perfectly into the LNB holder, and once mounted the distance and polarization rotation can easily be adjusted for best SNR. He also found that adding a secondary sub-reflector about 17x17cm in size helped to boost SNR by about 3-5 dB too.

Build steps to use the Active L-band Patch with a Satellite Dish
Build steps to use the Active L-band Patch with a Satellite Dish

Bert has tested the active L-band patch as a feed on a 65cm satellite dish and a smaller 40cm dish, both with good results.

SNR Results
SNR Results

Meteor M N2-2 Has Failed but Recovery May be Possible

UPDATE: It has now been confirmed by Roscosmos that the satellite was struck by what is presumed to be a micrometeorite which caused a leak of thermal transfer gas, and hence a sudden orbit change. It seems unlikely that the satellite will begin operations again as the satellite cannot operate it's camera sensors without thermal cooling. Data is being transmit currently on the X-Band, however, it appears to be a stored image only, rather than live images.

On December 18, 2019, an abnormal situation was recorded on the Meteor-M spacecraft No. 2-2 associated with an external impact (presumably a micrometeorite) on its structure. As a result, he changed the parameters of the orbit and switched to a non-oriented flight mode with high angular velocities.

In accordance with the inherent logic of operation, the device stopped fulfilling the target task and automatically switched to energy-saving mode when the on-board systems that were not involved in ensuring its functioning (including all on-board target equipment) are turned off.

After entering into the zone of Russian ground-based controls with the Meteor-M spacecraft No. 2-2, communication was established and work began to restore its operability: damping angular velocities, transferring to the standard orientation, receiving telemetric and target information.

Currently, work is underway with the satellite under the program of the chief designer. Meteor-M No. 2-2 is in an oriented flight; regular control sessions are conducted with it to receive telemetric information and information from target equipment.

Happysat's Notes:

Depressurization caused gas that was inside and used for heat transfer to leak out.

Resulting in some devices onboard overheating, while others did stop working.

Batteries are working under harsh thermal conditions.

Experts analyzing MSU-MR images during the incident to confirm collision.

------------------------- Original Post -------------------------

On December 18 Meteor M N2-2 suffered a failure that appears to have changed it's orbit. Roscosmos is quiet on the issue, but speculation by R4UAB is that there was a depressurization or on board explosion. However, Happysat who appears to be in contact with Roscosmos insiders has noted that on December 20 the orbit has been stabilized, and that they are working on recovering the operation of the satellite. Currently the LRPT signal and all sensors remain OFF.

Meteor M N2-2 is a Russian weather satellite that was successfully launched into orbit on July 5 2019. Like with the NOAA and Meteor M N2 satellites, it is possible to receive weather satellite images from this satellite with an RTL-SDR (when it is operational).

The older but still operational Meteor M2 satellite has failed several times in it's history too, each time with the satellite entering an unstable tumble. However, each time the satellite was recovered back into full operation after a few days.

The Meteor-M2 Satellite
The Meteor-M N2-2 Satellite

Tech Minds Demonstrates Iridium Live on a Raspberry Pi

Over on YouTube Tech Minds has uploaded a video of him demonstrating Iridium Live plotting Iridium satellite tracks in real time. We just posted about Iridium Live yesterday. It is a new program by microp11, who is also the author of Scytale-C, a useful Inmarsat STD-C decoder. The software works with gr-iridium to visualize Iridium satellite tracks as they pass overhead.

In the video Tech Minds runs the software on a Raspberry Pi with an Airspy. The current video is only a demonstration, but in the near future he promises to upload a full tutorial

IridiumLIVE - Real Time Visualization Of Iridium Satellites - Raspberry Pi

IridiumLive – New Software to Plot Iridium Satellites as They Pass Overhead with an RTL-SDR

Over on GitHub, microp11, the author of Scytale-C has released a new browser based program called IridiumLive which allows you to visualize the live positions of Iridium satellites as they pass overhead. Iridium is a satellite constellation that provides services such as global paging, satellite phones, tracking and fleet management services, as well as services for emergency, aircraft, maritime and covert operations too.

The software uses gr-iridium as the data source, which is an RTL-SDR and other SDR compatible Iridium satellite decoder. See this very interesting talk by the gr-iridium authors for more information, and this video by Techminds which shows how to install and run gr-iridium.

Also in order to receive Iridium satellites in the first place, you'll need an appropriate antenna such as our "RTL-SDR Blog Active L-Band 1525 - 1637 Inmarsat to Iridium Patch Antenna Set" which is currently available on our store.

Instructions for installing and running IridiumLive are available on the Git readme. Once installed you can browse to the IridiumLive web page on your local network, and view the tracks of the Iridium satellite fleet as they pass overhead, as well as the locations of Iridium signal activity from the ground.

IridiumLive Screenshot
IridiumLive Screenshot

Tech Minds: LoRa Text Chat with Two Othernet Dreamcatcher Boards

Back in the middle of last year we posted about Othernet's Dreamcatcher hardware and the LoRa chat application. The Dreamcatcher is Othernet's receiver and computing platform that is designed for receiving their satellite data broadcast. It is currently available for US$79.

Although the Othernet datacast is one way receive only, the Dreamcatcher board uses a LoRa radio chipset that has TX capabilities that can be leveraged for experimental purposes. One experimental piece of software that they developed is a chat application that works with two Dreamcatcher boards. It allows you to initiate a text based chat between two boards using the on board LoRa radio chips.

The TechMinds YouTube channel has recently released a video demonstrating the chat application in action, and the video shows how to set up, install and use it too. We note that since our post last year, the Dreamcatcher board has gone through a revision and no longer includes an LCD screen. The company name has also changed from "Outernet" to "Othernet".

What can you do with two Othernet Dreamcatcher Boards?

Building a FossaSat-1 LoRa IoT Ground Station

FossaSat-1 is a recently launched open source "picosatellite" with an onboard LoRa repeater designed for Internet of Things (IoT) communications. It was launched via the Electron Rocket in New Zealand on December 6. At only 5 x 5 x 5cm in size and 250g in weight, a picosatellite is a tiny satellite that fits in your hand and can be affordably built and launched for around US$40k. 

Since the launch, it has been confirmed that FossaSat-1 was successfully launched, and is working correctly. However, the antennas have not properly deployed yet resulting in a weak signal that cannot be received by small ground stations. The team are currently working on getting the antenna manually deployed from earth and the latest updates can be found on their Twitter @FossaSys. They note that if the antennas cannot be deployed, then there is still the future launches of FossaSat-1B and FossaSat-2 to look forward to.

While waiting for the antennas to deploy you can watch Andreas Speiss' YouTube video where he explains the satellite in more detail, and shows how to build a FossaSat-1 ground station that can receive the FossaSat-1 LoRa transmission and upload it to the internet. While not SDR-related as it uses a hardware based LoRa chip, this is still an interesting project that some readers may be interested in.

We build a 20 Dollars LoRa Satellite Ground Station and we follow the FossaSat-1 launch

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