Tagged: satellite

Comparing Two LNA’s for HRIT/LRIT (GOES) Reception

Over on his blog Lucas Teske has been comparing the LNA4ALL and an SPF5189 LNA from eBay on HRIT/LRIT reception from GOES satellites. SPF5189 LNA’s can be found on eBay for less than $8 USD, with free shipping from China, whereas the LNA4ALL costs 27 Euros shipped from Croatia. GOES is a geosynchronous orbit weather satellite which requires a satellite dish or other high gain antenna to receive. It downlinks at about 1.7 GHz, which means that a high quality LNA with low noise figure and good PCB design is needed for reception.

In his post Lucas mentions how he saw a review on eBay stating that the SPF5189 did not work at L-band. However, he found that odd as all of his SPF5189 LNA’s seemed to work just fine with L-band reception. So he did a benchmark comparing the SPF5189 to the PSA5043+ based LNA4ALL which is known to work well on L-band.

From his comparisons he found that the SPF5189 does indeed work well on L-band, and is comparable to the LNA4ALL. He concludes that the reviewer must have received a bad unit, or didn’t know what he was doing.

Lucas also makes an important note regarding the PCB design of these LNA’s. Even though the SPF5189 and PSA5043 chips have similar specs, with LNA’s the design of the PCB is crucial, as a poor design can significantly degrade performance. With the LNA4ALL you can be sure that the design is good, although the SPF5189 LNA’s currently on eBay look to be designed okay as well. Though with some eBay sellers there is no guarantee that you will receive a good board. We note that we have seen some really poor designs for PSA5043 LNA’s out there as well.

The eBay SPF5189 LNA vs the LNA4ALL from 9A4QV
The eBay SPF5189 LNA vs the LNA4ALL from 9A4QV

A New Meteor M LRPT Image Decoder for Windows, Linux, MacOS and Raspberry Pi

Thanks to twitter user @LinuxSocist for submitting a link to this new Meteor M weather satellite LRPT decoder called ‘meteor_decoder’ which can be run on both Linux and Windows. Pre-built binary of the software for Windows, Linux Raspberry Pi and MacOS are available at orbides.org.

This software decoder appears to be an excellent choice for those people who want to perform their reception and decoding of Meteor M satellites all in Linux. Previously as explained in this previous post, you were able to receive the QPSK data in Linux with an RTL-SDR and a GNU Radio program, but then you’d still need to boot into Windows or run Wine to run LRPTofflinedecoder in order to generate the image. Now it appears that the image generation can be performed natively in Linux too with meteor_decoder. This help with creating portable automated Raspberry Pi based Meteor M decoder servers.

Meteor M is a class of Russian weather satellites that transmit live weather images of the earth as they pass over your location. They are somewhat similar to the NOAA satellites, although the Meteor satellites transmit higher quality images via a digital LRPT signal, rather than the analog APT signals used by NOAA. With an RTL-SDR, an appropriate antenna and decoding software they can easily be received.

An Example LRPT Image Received with an RTL-SDR from the Meteor-2 M2.
An Example LRPT Image Received with an RTL-SDR from the Meteor M-N2 Satellite.

New Outernet Hardware “Dreamcatcher”: An RTL-SDR with Embedded Computing Hardware

Over on the Outernet forums Outernet CEO Syed has just released pictures of the latest upcoming Outernet receiver called “Dreamcatcher”. The new receiver is an RTL-SDR, LNA, filter, and embedded Linux capable computing hardware all on board a single PCB. The full specs are pasted below:

  • L-band SAW filter (1525 – 1559 MHz)
  • Two-stage L-band LNA with 34dB gain
  • 0.5 PPM TCXO
  • RF bypass for tuning from 24 – 1600 MHz – use as a regular RTL-SDR!
  • USB ports
  • GPIO forest
  • UARTs, I2C, SPI headers (unpopulated) for driving external hardware
  • Two microSD card holders – for boot and storage!
  • 1 GHz CPU
  • 256 MB RAM Now 512 MB RAM
  • USB wifi dongle (not shown) – STA+ AP mode capable!
  • Lots of LEDs! and Switches!
  • microUSB OTG
  • microUSB power port
  • Audio In/Out
  • Speaker with 1.4 W integrated audio amplifier
  • Fully mainline (4.10) Kernel and (2017.01) Uboot support!
    *** JST battery is being removed

On the Roadmap:

  • armbian/debian support

This is a fully-integrated SDR receiver – RF frontend, SDR, Compute, Wifi – Everything!

Outernet is an L-band satellite service that aims to be a download only “library in the sky”. Currently they are broadcasting from Inmarsat and Alphasat geostationary satellites which can be received from almost anywhere in the world. We have a tutorial on receiving and decoding their signal here. Every day almost 20 MB of data is sent down, and this includes data like news, weather forecasts, APRS, wikipedia articles, books and more. In the future you will be able to pay to upload private files or messages. This could be useful for sending messages to people isolated from cell phone reception, or for operating remote hardware.

Previously Outernet sold a DIY version of their receiver which included an RTL-SDR V3 or E4000 dongle, LNA+filter, a C.H.I.P embedded computer, and a patch antenna. Recently they have changed to their custom RTL-SDR hardware which is called the “SDRx”. The SDRx includes the RTL-SDR, LNA and filter on a single PCB. Over time it seems that they are moving in the direction of integration of all components onto a single PCB and this can be seen in the Dreamcatcher which now also includes the computing hardware. This is especially good news as the $9 C.H.I.P computing hardware has been almost impossible to acquire since its release.

The Dreamcatcher looks to be also not just useful for Outernet, but also for general projects that can be done on embedded hardware as there is a port which bypasses the L-Band filter.

Back in 2014 we posted about the XiOne. This was also to be an RTL-SDR and computing hardware built onto the same PCB. It would have been controlled via a WiFi connection and apps on a smart phone/tablet. Unfortunately the XiOne Indiegogo crowdfunding campaign never reached its target so the project faded away. The Dreamcatcher is somewhat similar in that both are RTL-SDRs with onboard computing hardware and WiFi connectivity.

The Dreamcatcher is not yet for sale, but it is currently under production. From the looks of the discussion on the forums, it looks like it will sell for $149 USD. Outernet have said that they are sending us a review sample, so keep an eye out for the review in the coming weeks.

The Outernet Dreamcatcher: RTL-SDR + LNA + Filter + Computing Hardware on a single PCB.
The Outernet Dreamcatcher: RTL-SDR + LNA + Filter + Computing Hardware on a single PCB.

—–Hz: A New STD-C Inmarsat Decoder

UPDATE: Unfortunately we have been informed that the code base of this software was illegally decompiled and reused in an almost unchanged way from an already available closed source decoder. This means the program itself is illegal and totally unethical.

Please respect the original developers hard work and do not download this software.

A new STD-C Inmarsat decoder called —-Hz has recently been released. The decoder is Windows based and simply listens to the demodulated Inmarsat STD-C audio from a program such as SDR#. This means that it is compatible with the RTL-SDR, and any other SDR that can receive Inmarsat. 

We gave the software a brief test and it ran very well, and managed to decode several SafeteNET messages without issue, maintaining a good lock most of the time. The author writes that he plans to improve on the software in the future by creating a web service based version of the software.

Currently there are two other Inmarsat decoders available. One is called InmarsatDecoder and the other is the Tekmanoid decoder. The InmarsatDecoder is generally regarded as the best, but the Tekmanoid decoder was recently updated for improved performance. The new software appears to be about the same as the Tekmanoid decoder.

Inmarsat STD-C messages are broadcast from geostationary satellites in the L-band at around 1.5 Ghz. They send mostly marine based messages such as the following quoted from the ——Hz website:

  • Safety: high seas, tropical storm warnings, ice accretion…
  • Shipping activity: moving oil rigs, submarine cable deployment and repairs…
  • Distress reports: MOB, ships lost at sea, migrant ship reports…
  • Military exercises (firing practice, no fly zones…)
  • Pirate at sea reports…

If you are interested in learning how to decode STD-C we also have a tutorial available here

The b4000Hz Inmarsat STD-C Decoder
The ——Hz Inmarsat STD-C Decoder

Building a DIY Carbon Fibre Yagi Antenna with 3D Printed Parts for 20€

Over on his blog author Manuel a.k.a ‘Tysonpower’ has written about a DIY Carbon Fibre Yagi antenna that he’s built for only 20€. The antenna is very lightweight thanks to a 12mm diameter carbon fibre pipe which is used as the main boom. It also uses 3D printed parts that clamp onto the carbon fibre pipe and hold the metal elements in place. The advantage of the carbon fibre pipe over a PVC one is not only is it lightweight and much easier to hold, but it also stronger, and much less bendy and floppy. The metal elements are welding rods which he found on eBay, and the carbon fibre pipe was sourced cheaply from China with Aliexpress. 

A Yagi is a directional antenna with high gain towards the direction it is pointing. You’ll need to hand point the Yagi in the general direction of the satellite as it passes over, but you can expect much higher SNR readings compared to something like a QFH or Turnstile.

Manuel designed his antenna for 2M satellites (NOAA, Meteor M2, ISS etc), and was able to achieve over 36 dB SNR with an RTL-SDR.com V3 receiver, FM Trap and LNA4ALL on NOAA 18 at a 34° max. pass. He writes that the design is easily modifiable for other frequencies too.

To show off the design, construction and performance of his antenna he’s uploaded two videos to YouTube which we show below. The speech is in German, but even for non-German speakers the video is easily followed

http://www.youtube.com/watch?v=bNsvUdHIliI
http://www.youtube.com/watch?v=UGdVRhsNFJU

Receiving GOES 16 Weather Satellite Images with the Open Satellite Project

Back in October/November of last year Lucas Teske showed us how to receive weather satellite images from the GOES line of geostationary satellites with an Airspy SDR (and possibly an RTL-SDR too), dish antenna and the decoding software that he created. 

On November 19, 2016 the next generation GOES 16 (aka GOES-R) satellite was launched by NASA. GOES 16 is a little different to the older GOES satellites as it has better sensors and is capable of capturing and transmitting a new image every 15 minutes which is quite fast. Thus a different and higher bandwidth RF transmission protocol called HRIT (High Rate Information Transfer) is used, compared to the LRIT (Low Rate Information Transfer) signal used on the older satellites.

Once the satellite started transmitting in January 2017, Lucas got to work on trying to create a decoder for the new satellite. After noticing some discrepancies between the published HRIT specs and the actual signal, Lucas sent off an email to NOAA and actually received an email back with the full specifications. With this information he was able to update his Open Satellite Project code and start decoding images from GOES 16.

The images being sent right now seem to just be relays of other similar satellites like Himawari-8 and Meteosat, as it seems that they are still testing the satellite. The relayed images received via GOES 16 received by Lucas can be seen on the Open Satellite Project twitter feed and on Lucas’ personal twitter feed.

Full disk image received via GOES 16, relayed from the Himawari-8 satellite.
Full disk image received via GOES 16, relayed from the Himawari-8 satellite.
Weather data received via GOES 16.
Weather data received via GOES 16.

Receiving GOES Weather Satellite Images with a Small Grid Antenna and an Airspy Mini

GOES is an L-band geosynchronous weather satellite service that can be received typically with a satellite dish. It produces very nice full disk images of the earth. In the past we’ve posted about Lucas Teske’s work in building a GOES receiving system from scratch (including the software decoder for Airspy and RTL-SDR receivers), devnullings post about receiving GOES and also this talk by @usa_satcom on decoding GOES and similar satellites.

Over on Twitter @usa_satcom has been tweeting about his experiments where he has been successfully receiving GOES L-Band weather satellite images with a small grid antenna and an Airspy Mini. In a Tweet he writes that the antenna is an $85 USD Hyperlink 1.9 GHz 22 dBi Grid Antenna made by L-com. A grid antenna may be more suitable for outdoor mounting for many people as they are typically lighter, smaller and more suitable for windy and snowy conditions. As the GOES satellite is in geosynchronous orbit, no tracking motor or tracking mount is required.


Outernet Patch Antenna Pan-Tilt Servo

Over on YouTube user Tomi Simola has uploaded a video showing his servo based Outernet satellite antenna tracker. Outernet uses L-band geostationary satellites which means that they are at a fixed position in the sky. Optimal reception of the Outernet and other L-Band satellite signals can be obtained by pointing the patch antenna towards the satellite.

Tomi wanted an easy way to remotely switch the antenna to point at one of two geostationary satellites, Alphasat at 25E which has the Outernet signal and Inmarsat at 64E which has more services like AERO and STD-C. Another potential use of his tracker might be for tracking L-Band satellite while in a moving vehicle such as a car or boat. 

To automatically point the Outernet L-band patch antenna Tomi used a commonly found Pan-Tilt servo mounted inside an waterproof enclosure. On the servo is a 3D printed mount which the patch antenna is attached on. An Arduino Nano with Bluetooth module allows control of the servo.

The video below shows a test of the system, over on Reddit he has written a comment explaining the project and over on Imgur he’s uploaded some photos of the construction.

https://www.youtube.com/watch?v=LGPxiUPJ7Eo