Tagged: satellite

Receiving Elektro-L3 LRIT Weather Satellite Images with an 11-Turn Helix Antenna and No Dish

Typically, a satellite dish is used to receive Elektro L3. As an example, our 70cm diameter Discovery Dish with linear feed can do this easily, and achieve an SNR of about 5-6 dB. However, as Meti shows, it is possible to receive this satellite even without a dish, and as he shows, an SNR of 1.5 dB is sufficient for decoding a perfect image.

Meti's antenna is an 11-turn RHCP helix made of copper wire, with a 17 x 17cm ground plane. In his post, he also notes a few interesting findings, noting that the height of the antenna off the ground is critical, rotating the helix can help, interference from cell towers can cause issues, and bending the corners of the ground plane can help.

In the rest of the post, Meti also shows how well the helix antenna works at receiving weather satellite signals from polar orbiting L-Band satellites like Meteor M2-3.

Meti's 11-Turn RHCP Helix Antenna
Meti's 11-Turn RHCP Helix Antenna

Using our RTL-SDR Blog Dipole as a V-Dipole for Receiving Weather Satellites

With our RTL-SDR Blog dipole antenna set, it is possible to use it in a "V-dipole" configuration to receive polar-orbiting weather satellites such as NOAA and Meteor at 137 MHz. More information on this can be found on our page at www.rtl-sdr.com/DIPOLE.

If you are after more visual instruction, "Baltic Lab" has uploaded a clear video on YouTube showing how to set the dipole leg lengths and angles correctly for weather satellite reception. 

We want to add that it is also important to remember to mount the antenna outdoors horizontally and in a north-south orientation with a clear view of the sky for the best results.

How To Build A V Dipole For Receiving Weather Satellites

IEEE Spectrum Article on Discovery Dish

Electrical engineering magazine IEEE Spectrum has recently posted an article about our Discovery Dish product, which was successfully crowd-funded on CrowdSupply and delivered to initial backers early this year. Discovery Dish is a 70-cm aluminum satellite dish with an active filtered feed. It is designed for receiving real-time weather data from GOES HRIT, GK-2A LRIT, FengYun LRIT, NOAA HRPT, Metop HRPT, Meteor M2 HRPT, and other weather satellites that operate around 1.69 GHz. There are also feeds for Inmarsat satellites, Hydroden Line observation, and S-band satellites.

In the article, Stephen Cass introduces the Discovery Dish, highlighting its practical uses and the convenience of disassembling it for easy packing in a suitcase during travel. He also shares his experience using the Discovery Dish to successfully receive images from the GOES-East satellite from the rooftop of his New York City apartment.

Finally, he mentions how he tested the hydrogen line feed as well, successfully seeing a hydrogen line peak when pointing at the galaxy.

Image from the IEEE Spectrum Article on Discovery Dish
Image from the IEEE Spectrum Article on Discovery Dish

Saveitforparts: Snooping on the SatGus Selfie Satellite

SatGus is a recently launched cubesat owned by CrunchLabs/Mark Rober, an extremely popular science and engineering YouTuber. The satellite is designed to take selfies of CrunchLabs customers' own photos in space, using a screen and a selfie camera mounted on the satellite. It then broadcasts the selfie image back down to a CrunchLabs ground station, where it is eventually emailed to the customer. Customers then claim that they've had their selfie taken in space.

Over on the saveitforparts YouTube channel, Gabe has been attempting to listen in on the SatGus downlink using a HackRF and a motorized satellite dish setup. SatGus transmits telemetry at 400.2 MHz and the payload dump at 2,262.5 MHz. While he is able to receive the signal, Gabe notes that it is encrypted, so not much can be done with it.

Snooping On SatGus Again

A 3D Printed V-Dipole Guide for the RTL-SDR Blog Dipole Kit

Thank you to Denis for submitting his 3D printable V-dipole guide for our RTL-SDR Blog Dipole Antenna set. The guide holes the dipole at a 120-degree V-shape angle, which is ideal for receiving polar-orbiting satellites such as NOAA and Meteor at 137 MHz. 

Back in 2017, Adam 9A4QV wrote about how a V-Dipole could be used as a very simple yet effective antenna for receiving weather satellites. Since then, it has become a popular beginner's choice for receiving weather satellites.

In the past, we've also seen other 3D-printed V-dipole holders, such as this one by f16v1per. However, f16v1per relies on cable ties to hold the elements in place, whereas the design by Denis simply slides in place.

If you don't have an RTL-SDR Blog Dipole Antenna, you can also build a V-dipole out of an electrical terminal block and a different 3D-printed part, as shown in this previous post.

3D Printed V-Dipole Holder
3D Printed V-Dipole Holder

Saveitforparts: Listening in on Russian Soldiers Hijacking US Military Satellites

Over on the saveitforparts YouTube channel, Gabe has uploaded a video showing how he uses WebSDR streams to show how Russians, including Russian soldiers, are using old US Military satellites for long-range communications around Ukraine.

In the '70s and '80s, the US government launched a fleet of satellites called "FLTSATCOM," which were simple radio repeaters up in geostationary orbit. This allowed the US military to easily communicate with each other worldwide. However, the technology of the time could not support encryption or secure access. So security relied entirely on only the US military's technological superiority of being the only one to have radio equipment that could reach the 243 - 270 MHz frequencies in use by these satellites. Of course, as time progressed, equipment that could reach higher frequencies became commonplace.

In the video, Gabe explains how many Russian soldiers involved in the Ukraine war are using these legacy satellites to communicate with each other. He notes that apart from voice comms, some channels are simply Russian propaganda and music, as well as some channels that appear to be jammed. Gabe also notes that the "UHF Follow-On Satellite" (UFO) satellites that were launched as recently as 2003 are also being hijacked, as they also have no encryption or secure access.

In the past, we also posted a previous video by Gabe about attempting to receive these satellites from his home in North America. However, on that side of the world, the satellites are being hijacked by Brazilian pirates instead.

Russia Is Hijacking US Military Satellites

Saveitforparts: Receiving Military DMSP Satellite Data with a Hacked TV Dish

Over on the saveitforparts YouTube channel, Gabe has uploaded a video showing how he uses a hacked TV satellite dish to receive satellite weather data from Defense Meteoroloogical Satellite Program (DMSP) satellites.

These satellites were initially developed during the Cold War and featured an encrypted downlink of meteorological data. However, recently, the DMSP downlink has encryption turned off when passing over the northern half of the USA (40°-41° latitude and up to 60° North), allowing hobbyists in some parts of the USA to decode images. 

In his video, Gabe uses a HackRF SDR with an old DirectTV dish with a modified S-band helical feed mounted on a hacked Wineguard motorized platform that was originally intended for automatically pointing TV dishes on RVs. Despite some initial problems with the SatDump software crashing, he is eventually able to receive some nice, clean images.

Interestingly, Gabe also shows what the signal looks like while encrypted and how it transitions to the unencrypted signal after the satellite passes over the threshold. 

We note that it is not documented by the military why encryption is being turned off only over the northern half of the USA. Still, it is speculated that the military doesn't consider images over this part of the USA to be sensitive, and disabling encryption could help save power and help other organizations with scientific research. However, as Gabe mentions in the video, being a Cold War-era satellite, the image quality from DMSP isn't great, and more modern satellites like the NOAA series give much better images over the entire earth unencrypted. 

Grabbing Military Satellite Data With Hacked TV Dish

Saveitforparts Checks out the Discovery Dish

Over on his YouTube channel 'saveitforparts,' Gabe has uploaded a video checking out and reviewing our Discovery Dish product that we successfully crowd-funded on CrowdSupply back in December 2023.

Discovery Dish is designed as a low-cost way to dive straight into backyard satellite experiments, including receiving L-band and S-Band weather satellites as well as Inmarsat satellites. It also offers an easy entry into making galactic Hydrogen line observations.

The dish is a 70cm prime focus dish, that can easily be broken down into three parts for easy storage and transport. The feeds are fully integrated, meaning that the feed antenna, LNA, and filtering are all in one unit and built into a waterproof enclosure. This means there is no need to purchase individual components and figure out waterproofing.

In his video, Gabe unboxes the Discovery Dish, builds it, and uses the L-band feed to receive a few images from GOES 16, Meteor M3, Meteor M4, and METOP weather satellites. He goes on to successfully test reception with the S-band feeds on NOAA weather satellites, before testing out the Inmarsat feed and successfully receiving signals. Finally, Gave notes that he hopes to test out the Hydrogen Line feed in a future video.

Checking Out The Discovery Dish - A Simple & Easy-To-Use Satellite Antenna For Everyone!