Tagged: satellite

GOES-U Satellite Launched and on the way to Geostationary Orbit

On June 25 the NOAA GOES-U weather satellite was successfully launched on a SpaceX Falcon 9 Heavy rocket. Once it reaches geostationary orbit, this will be a new weather satellite that RTL-SDR hobbyists can receive with an RTL-SDR dongle, satellite dish, and LNA.

From launch, it will take about two weeks for GOES-U to reach geostationary orbit and once it gets there it will be renamed to GOES-19. It is due to be positioned where GOES-16 currently is, and GOES-16 will become the redundant backup satellite. This positioning will make the satellite visible to those in North and South America.

GOES-16 is where GOES-19 will be positioned.
GOES-16 is where GOES-19 will be positioned.

We are anxiously looking forward to the first images from GOES-19 received by hobbyists, but once positioned it will probably take several weeks to be tested and calibrated before hobbyists can receive any signals on L-band. 

Over on X, @WeatherWorks posted a short video showing that the launch plume was visible from GOES-16.

The @CIRA_CSU account has also posted a video from GOES-18 which shows the launch in the water vapor bands

Finally, @SpaceX has also posted a video showing the deployment of the satellite, with an impressive shot showing how far away it is from the Earth.

YouTube Video Series on Iridium Satellite Decoding with an Airspy, RTL-SDR Blog Patch Antenna and DragonOS

Over on his YouTube channel, Rob VK8FOES has started a new video series about Iridium Satellite Decoding. Iridium is a constellation of low-earth orbiting satellites that provide voice and data services. Iridium was first decoded with low cost hardware by security researchers back in 2016 as mentioned in this previous post. Being unencrypted it is possible to intercept private text and voice communications.

Rob's video is part of a series, and so far only part one has been uploaded. The first video outlines the hardware and software requirements for Iridium decoding and demonstrates the gr-iridium software. An Airspy and RTL-SDR Blog Patch Antenna are used for the hardware, and the software runs on DragonOS.

Rob writes that in part two he will demonstrate the use of iridium-toolkit, which can be used to extract data and recordings from the Iridium data provided from gr-iridium.

Be sure to subscribe to his YouTube channel so that you are notified when part two is released.

Iridium Satellite Decoding Part 1: The Tutorial That Goes Over Your Head, Literally!

Gypsum: A Software-Defined GPS Receiver written in Python + A Writeup on How it Was Made

Thank you to RTL-SDR.COM reader Lee. who found a recently released program called "gypsum" which enables an RTL-SDR or HackRF to be used as a GPS Receiver when combined with a GPS antenna. Phillip Tennen, the author of Gypsum notes that Gypsum can obtain a fix within 60 seconds from a cold start and that it has no dependencies apart from numpy. We want to note that it appears that Gpysum has no live decoding ability yet, as it works from pre-recorded GNU Radio IQ files.

In the past, we've shown in a tutorial how GPS can be received and decoded with GNSS-SDRLIB and RTKLIB on Windows. The new Gypsum software should work on Linux and MacOS too.

What's more, Phillip has written an incredible 4-part writeup on how Gypsum was implemented from scratch. In the write-up, Phillip introduces GPS and explains how it can even work with such weak signals that appear below the thermal noise floor. He then goes on to explain how the detected signal is decoded and turned into positional information, and how challenging it was to propagate the accurate timing information that calculating a solution requires. The write-up is presented with clear visualizations to help readers intuitively gain an understanding of the advanced concepts involved.

Gypsum GPS Satellite Tracking Dashboard GUI
Gypsum GPS Satellite Tracking Dashboard GUI

Testing a WiFi Grid Antenna for L-Band Satellites

Over on YouTube dereksgc has uploaded a video where he tests out a 2.4 GHz WiFi Grid antenna for L-band weather satellite reception. WiFi grid antennas are typically repurposed in the SDR community for L-Band weather satellite reception because they are cheap and mostly work out of the box. They can also be used for hydrogen line radio astronomy. TV dish antennas are an alternative but with them, a custom feed needs to be built. 

In his video, dereksgc tests the WiFi dish on receiving various polar-orbiting L-band satellites including Metop, and Meteor M2. With the polar orbiting satellites the dish needs to point at the satellite as it passes over the sky and so dereksgc recommends using a mount if hand tracking them.

Later in the video he tests some geostationary satellites but finds that the dish is not tuned well enough to receive Elektro-LN3 properly without modifications. He was however able to receive a noisy image from FengYun-2H successfully.

We note that we also currently have our Discovery Dish product available for pre-order, which is similar to the WiFi grid dish, but smaller and lighter weight with a built-in optimized active feed.

I finally got a WiFi grid antenna for satellites

Saveitforparts: Receiving and Decoding L-Band Weather Satellites

Over on his YouTube channel 'saveitforparts' has uploaded a new video showing how he has been successful at receiving and decoding L-band weather satellites using his setup made from scavenged parts. He uses a custom-built helical feed on a scavenged dish, and an automatic pan-tilt rotator built from an old security camera mount. With this setup combined with an RTL-SDR and LNA and filter he is able to receive polar orbiting L-band weather satellites. 

In the video, he shows how his system works and what his software setup looks like. He uses SDR++ to record the pass initially, then SatDump to decode the data into images. We note that SatDump can be used to decode the images live, and can also record the raw radio files too, so SDR++ is not required.

How To Receive And Decode L-Band Weather Satellites

Meteor M2-4 has not failed – it is still in the testing phase

Thank you to Robin OK9UWU who wanted to point out that the recently launched Russian Meteor M2-4 weather satellite has not failed. There have recently been rumors and videos being spread online claiming that the satellite has already failed as the LRPT and HRPT signals are currently offline.

However, the satellite is still in a testing phase and was only briefly transmitting images for a few days after launch. It is difficult to find official updates from Roskosmos, the Russian space agency, but Robin explains his thoughts on what is happening:

The satellite in question, Meteor-M N°2-4 did not fail. The reason for both the LRPT and HRPT transmitters to be off is that the primary instrument (MSU-MR) is currently undergoing a routine cleaning process to get the IR channels up and running correctly.

It's completely normal.

Other reason why it's off could be that they are testing the MeteoSAR instrument (2-4 is the first sat of this series to have this), hence why unnecessary radios might have been taken offline.

It's important to understand that these satellites are being used to do actual science, weather forecasting etc. They require careful testing and calibration which might take some time. It's not just for "cool imagery".

For example, it took months to get the VIIRS instrument running onboard of the NOAA-21 satellite.

Keep calm and nerdy!

spaceintel101.com's infographic about the Meteor M2-4 Launch
spaceintel101.com's infographic about the Meteor M2-4 Launch

Saveitforparts: Building a Satellite Antenna from an Emergency Blanket and a Rotator from an old Security Camera Mount

Over on his YouTube channel, 'saveitforpaarts' has uploaded two new videos. The first shows how he was able to build a very cheap satellite antenna for GOES satellites out of an umbrella and a metallic emergency blanket. The blanket is simply spread over the inside of the umbrella, creating an RF reflective surface. Then a linear feed with LNA and amplifier is placed at the feed point. The makeshift dish works, though the SNR is marginal, and he is only able to receive slightly corrupted images from GOES satellites.

Satellite Antenna Made From Emergency Blanket

In his second video saveitforparts builds a satellite dish rotator out of an old thrown away security camera pan/tilt mount. The mount is hacked to be controllable via an Arduino microcontroller. 

I Built A Cheap Satellite Tracking System From Spare Parts

Receiving SSTV From the Russian UmKA-1/RS40S Cubesat

YouTuber 'saveitforparts' was recently contacted by the ground controller of the Russian UmKA-1/RS40S cubesat asking if he'd like to try and receive an SSTV image from the satellite. UmKA-1/RS40S is a small educational satellite assembled by a Russian high school. Originally it was intended for a radio astronomy experiment, but due to technical issues it's been switched to the secondary ham radio mission only.

Saveitforparts uses an RTL-SDR, directional Yagu antenna, PC running the MMSSTV decoder, and Android phone running the Stellarium satellite tracking app. After a few failed attempts he was able to eventually successfully track and receive the SSTV image as well as some telemetry.

We note that the SSTV image appears to have been specifically scheduled for saveitforparts personally, so if you try to receive this satellite yourself you will probably only be able to receive the telemetry signal.

Receiving Targeted Message From Russian Satellite