Every month SDR evangelist Balint Seeber hosts the Cyberspectrum Meetup in San Francisco, where many SDR fans come together to listen to various presentations. The 20th Cyberspectrum SDR meetup has now concluded, and the recorded video is available on YouTube.

The talks this time include a very interesting talk by Joe Steinmetz (@usa_satcom) about decoding L-Band weather satellites such as NASA GOES. Previously we made a post regarding GOES where Reddit user devnulling showed his GOES reception setup. To save time, on the video Joe’s talk starts at 00:10:45.

This presentation will cover most aspects of receiving, demodulating and decoding current L-Band Weather Satellite signals (NOAA, MetOp, Meteor, FengYun, GOES). Topics will include hardware, software, de-modulation/decoding techniques, challenges, flows as well as cool sample images and data.

 The second talk is titled “Disposable, Stealthy, Cheap SIGINT” is by Chris Kuethe, @kj6gve and delves into topics relating to low cost signal analysis. Chris’ talk starts at 1:45:00. The blurb reads:

This presentation covers some observations and considerations for using inexpensive and compact ARM boards for signals analysis.  Topics may include: power budget, air interface, attributability, performance tuning, lolcats and doges.

The post The 20th Cyberspectrum Software Defined Radio Meetup appeared first on rtl-sdr.com.

Outernet is a new L-band satellite services which aims to be a “library in the sky”. Their satellite signal can be received from almost anywhere in the world, and they aim to constantly transmit data like news, weather updates, books, images/videos and other data files. The service is free and can be received with an RTL-SDR, LNA and patch antenna. We have a full tutorial on receiving their service available here.

The “rxOS” decoder, file management system and web interface GUI has recently been updated to version 3.0. This new version has several new features:

1. Downloaded files are automatically decompressed after downloading, so they can be viewed directly in the Outernet web interface.
2. An hourly transmission of APRS data which comes from the repeater on board the international space station. APRS messages can now be relayed across the world via the ISS and Outernet.
3. This Monday they will begin transmitting NOAA weather data (we are unsure if this entails images or text data yet)
4. Soon they should begin transmitting news data too.

More details on the update can be found on their forum post. To update the service on a CHIP or Pi 3, download the .pkg file from the links on the forum and choose this file in the Update Firmware section of the Outernet settings menu. 

The post Outernet rxOS Version 3 Released: Automatic Decompression, APRS, NOAA Weather Data, News Updates appeared first on rtl-sdr.com.

Over on his YouTube channel Adam 9A4QV has uploaded a new video showing reception of L-band signals with a bias tee powered LNA4ALL and a small patch antenna. The video seems to show a new miniature bias tee powered LNA4ALL device that Adam might be working on. The LNA4ALL is a low noise amplifier that works well with our bias tee capable RTL-SDR dongles.

The patch antenna is made out of a single piece of PCB board which was made by etching out the patch pattern with masking tape. While the patch antenna is not optimal, and tested indoors, Adam is still able to receive some AERO signals.

Later in the video he compares the PCB patch against a GPS patch antenna which gets no reception. He also compares the results when two LNA4ALL’s are used in series. Using two LNA’s improves reception slightly.

The post L-Band Setup with Mini LNA4ALL and Mini Patch Antenna appeared first on rtl-sdr.com.

A few days ago we reported that the Outernet L-band satellite service had just upgraded their software to make it available for receiving APRS and weather updates. Back then it wasn’t clear what the weather updates would entail. Today weather updates starting being transmitted. They are using NOAA data and displaying it on a live weather app (which can also be viewed online here).

The app can be used to view weather data such as wind vectors, temperatures, relative humidity, total precipitable water, total cloud water, mean sea level pressure and ocean currents. Outernet writes that the global weather data will be updated via their satellite system once per day, and that each update also provides 24h, 48h and 72h predictions. 

We also see that grib files for mariners are now coming in as well as several Wikipedia articles and regular APRS broadcasts from the ISS.

It looks like the Outernet service is becoming more and more useful over time. If you are interested in receiving Outernet with an RTL-SDR see our tutorial post here.

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Outernet is a satellite based file delivery service. Currently they’re beta testing their service and they are using RTL-SDR’s as the receiver. In previous posts we’ve seen that they’re now regularly transmitting weather updates, wikipedia files and more files like images and books. Over time the service is becoming more and more useful. If you’re interested in receiving their service we have a tutorial available here.

While most of the Outernet software is open sourced, the signal protocol itself is closed source, which ties you into needing to use the official Outernet software. Over on his blog, Daniel Estévez has been working on reverse engineering the Outernet signal with the goal of publishing the results and building a fully open source receiver.

So far he’s managed to fully reverse engineer the modulation, coding and framing. He’s also been able to build a GNU Radio program that receives the Outernet frames and a Python program called free-outernet which does the decoding. His post goes into greater details on how he reverse engineered the signal and what his finding are.

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Many people with an RTL-SDR have had fun receiving NOAA and METEOR low earth orbit (LEO) weather satellite images. However, a step up in difficulty is to try and receive the geostationary orbit (GEO) weather satellites like GOES. These satellites are locked to a fixed position in the sky meaning there is no need to do tracking, however since they are much further away than LEO satellites, they require a 1m+ satellite dish or high gain directional antenna to have a chance at receiving the weak signal. The GOES satellites transmit very nice high resolution full disk images of the earth, as well as lots of other weather data. For more information see this previous post where we showed devnulling’s GOES reception results, and this post where we showed @usa_satcom’s presentation on GOES and other satellites.

Over on his blog and Twitter account (@lucasteske) Lucas Teske has been documenting his work in building a GOES receive system. The SDR he uses mostly is an Airspy, but recently he showed that our RTL-SDR Blog V3 dongle is also capable at receiving the GOES signal.

The nice thing about Lucas’ post is that he documents his entire journey, including the failures. For example after discovering that he couldn’t find a 1.2m offset satellite dish which was recommended by the experts on #hearsat (starchat), he went with an alternative 1.5m prime focus dish. Then after several failed attempts at using a helix antenna feed, he discovered that his problem was related to poor illumination of the dish, which meant that in effect only a small portion of the dish was actually being utilized by the helix. He then tried a “cantenna”, with a linear feed inside and that worked much better. Lucas also discovered that he was seeing huge amounts of noise from the GSM band at 1800 MHz. Adding a filter solved this problem. For the LNA he uses an LNA4ALL.

To position the antenna Lucas used the Satellite AR app on his phone. This app overlays the position of the satellite on the phone camera making it easy to point the satellite dish correctly. He also notes that to improve performance you should experiment with the linear feeds rotation, and the distance from the dish. His post of full of tips like this which is very useful for those trying to receive GOES for the first time.

In future posts Lucas hopes to show the demodulation and decoding process.

The post Setting up a GOES Weather Satellite Antenna System appeared first on rtl-sdr.com.

Last week we posted about Lucas Teske’s (@lucasteske) experience with setting up an antenna system that can receive the geostationary GOES weather satellites. He set up a dish antenna, feed, LNA and filter and was able to successfully receive the GOES signal with an RTL-SDR and Airspy.

Now Lucas has uploaded his second post where he discusses how to demodulate the GOES signal. The GOES satellites transmit a Low-Rate Information Transmission (LRIT) signal which contains full disk images of the earth as well as other weather data from the secondary Emergency Managers Weather Information Network (EMWIN) signal.

In order to demodulate the signal Lucas wrote a BPSK demodulator in GNU Radio. His post goes into good technical detail and shows exactly how the demodulator is constructed. Basically the the BPSK signal is first decimated down to 2.5e6, normalized with an AGC, then cleaned up with a Root Raised Cosine Filter. From there the signal goes through a Costas Loop PLL to receover the carrier wave, then a Clock Recovery MM block to recover the symbol clock. The data is then output to a TCP pipe for the decoder.

In the upcoming third part of his article Lucas will show us how to actually turn the demodulated data into an image of the earth.

The post Creating a GOES Weather Satellite Demodulator appeared first on rtl-sdr.com.

Yesterday we posted about Lucas Teskes (@lucasteske) success in building a demodulator for the GOES weather satellite. Before that he also showed us how to build an antenna system to receive GOES with an Airspy or RTL-SDR dongle.

Today Lucas continues with part three of his series on GOES decoding. This time he shows how he has built a frame decoder to process the output of the demodulator, and also gives us a link to his code. The decoder is written in C code. Lucas’ post explains how to sync the frame by detecting the preamble, perform convolution encoding to generate a parity and help correct any errors, and decode the frame data.

In part four Lucas will show us how to parse the frame data and extract the packets which will eventually form an image file of the earth.

The post Building a Frame Decoder for the GOES Weather Satellite appeared first on rtl-sdr.com.

In his latest two posts Lucas Teske continues with his series about receiving and downloading weather satellite images from the GOES satellites. In past posts he’s show us how to receive the signal with a satellite dish and Airspy or RTL-SDR (part 1), how to demodulate the signal (part 2), and how to extract frames from the demodulated signal (part 3). Lucas has recently completed his series with parts 4 and 5 having just been uploaded.

In part 4 Lucas shows how to parse the frames and get the packets which will ultimately be used to generate the weather image files. His post explains how to de-randomize the frame data which is initially randomized to improve performance, how to add Reed Solomon error correction, how to demux the virtual channels and the packets and finally how to save the raw packet.

In part 5 Lucas shows us how to finally generate weather satellite images from the GOES satellites. He notes that there is a problem with the LritRice compression method used by NOAA, because the library is currently broken on Linux. So he made a workaround which involved making a Windows application that runs through Wine for decompressing the data. Once the files are decompressed he uses the xrit2pic program which can open the generated .lrit files and convert them into images.

In the future Lucas mentions that he will write a user guide to his LRIT decoder, and make the whole decoding process more user friendly for people who do not care so much about the actual decoding process. Below are some images that Lucas was able to receive with his system.

The post Demuxing Frames and Generating Images from the GOES Weather Satellite appeared first on rtl-sdr.com.

Akos from the RTLSDR4Everyone blog has recently uploaded four new articles. The first article reviews the new FlightAware Prostick Plus. The Prostick Plus is an RTL-SDR dongle optimized for ADS-B reception. It contains a LNA and 1090 MHz filter on board the dongle. In his review Akos tests the FlightAware Prostick Plus and compares it against the regular Prostick with external filtering. His results show that the Prostick Plus gets 18.45% more position reports and 5.4% extra max range in his location. His second post continues with the Prostick topic and warns customers to look out for sellers reselling, or relisting the Prostick for much higher ripoff prices.

In his third post Akos reviews our RTL-SDR.com broadcast FM filter and compares it against another similar filter from another seller. His test results show that both filters can improve performace.

Finally in his fourth post Akos writes a tutorial on getting started with Outernet reception. He bought the full Outernet bundle which comes with a battery bank, CHIP single board computer, E4000 with bias tee RTL-SDR, LNA with filter and patch antenna. His post describes what each component is, then shows how to use them to receive Outernet. His results also seemed to show that our V3 dongle significantly outperformed the E4000 dongle at Outernet reception. The V3 received the Outernet signal with a SNR of 6.39 dB vs only 2.58 dB with the E4000.

The post RTLSDR4Everyone Four New Posts: FlightAware Pro Stick Plus Review, Avoid FlightAware Ripoffs, Review of two BCFM Filters, Getting Started with Outernet appeared first on rtl-sdr.com.

Over on YouTube Adam 9A4QV has uploaded a video showing how to build a DIY bandpass filter for 137 MHz. This can help improve the reception of NOAA and Meteor M weather satellites, by blocking strong out of band signals. Adams design is a 132 MHz – 142 MHz Butterworth bandpass filter which gives about 35 dB attenuation outside of the pass band. He’s also posted a write up documenting the filter design on his website.

Lucas Teske recently went ahead and built the 137 MHz filter suggested by Adam. Lucas didn’t have the correct capacitor values so he ended up cascading several in series. His results showed that the filter did improve his reception significantly.

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Outernet is a relatively new satellite based file delivery service which can be received with an RTL-SDR dongle. They continuously send out useful data like weather reports, news, APRS data as well as files like Wikipeda pages, images, videos and books. Previously we posted a tutorial that shows how to set up an Outernet receiver here.

If you instead prefer video tutorials, then two YouTube channels have uploaded Outernet set up tutorials. The first tutorial is by MKme Lab. In this video they set up Outernet using a Raspberry Pi and a Lipo battery for portable operation. Once setup he shows the Outernet browser and weather app in action.

The second video is by John’s DIY Playground and is similar, but goes a bit deeper into setting up the software on the Raspberry Pi and shows how to point the patch antenna towards the satellite.

The post Two Videos That Show How To Set Up An Outernet Receiver appeared first on rtl-sdr.com.

Akos from the radio for everyone blog (formerly known as the rtlsdr4everyone blog) has uploaded two new posts. On the first post he shows some further tests on the new FlightAware Prostick plus. The Prostick is an RTL-SDR that contains a built in LNA and the Prostick plus adds an additional SAW filter on the stick. For him the Prostick Plus works significantly better than the regular Protstick + external FA cavity filter and also gets about twice the ADS-B reception reports as our V3 which does not use an additional internal LNA. Next week we hope to release our own review of the Prostick Plus, and we’ll hopefully be able to show and explain why some people see better performance with the plus and why some instead see degraded performance.

In his second post Akos shows a tutorial on building an easy helical antenna for Outernet reception. The antenna is constructed from readily available household materials such as a soda bottle, coax cable, electrical tape and a cookie tin. With the cookie tin used he was able to get a SNR reading between 7 – 9 dB, which is pretty good considering that only 3 dB is required for Outernet decoding to work.

The post Radio For Everyone: An Easy Homemade Outernet Antenna, More FlightAware Pro Stick Plus Results appeared first on rtl-sdr.com.

The International Space Station periodically schedules radio events where they transmit Slow Scan Television (SSTV) images down to earth for listeners to receive and collect. This time they have scheduled SSTV images for Dec 8 1235 – 1800 UTC, and December 9 1240-1740 UTC. The ARRL announcement reads:

Slow-scan television (SSTV) transmissions from the International Space Station (ISS) are scheduled for December 8-9. The SSTV images will be transmitted from RS0ISS on 145.800 MHz FM as part of the Moscow Aviation Institute MAI-75 Experiment, using the Kenwood TM-D710 transceiver in the ISS Service Module.

MAI-75 activities have been scheduled on December 8, 1235-1800 UTC, and December 9, 1240-1740 UTC. These times correspond to passes over Moscow, Russia. ISS transmissions on 145.800 MHz FM use 5-kHz deviation, and SSTV transmissions have used the PD120 and PD180 formats.

The ISS Fan Club website can show when the space station is within range of your station. On Windows PCs the free application MMSSTV can decode the signal. On Apple iOS devices, use the SSTV app.

These SSTV broadcasts can usually be easily heard with an RTL-SDR and appropriate satellite antenna such as a QFH, Turnstile or a hand held Yagi. Many listeners have reported in the past as being able to receive them even with non-satellite antennas such as discones, ground plane, rubber duck and long wire antennas, so try your luck even if you don’t have the right antenna.

We recommend using the Orbitron software to track the ISS, but you can also use the web tracker on issfanclub.com as recommended by the ARRL.

The post SSTV From the ISS Scheduled for Dec 8 – 9 appeared first on rtl-sdr.com.

Over on YouTube Adam 9A4QV has uploaded a video showing us his home made cooking pot L-band antenna. The antenna consists of a large aluminum cooking pot which acts as a reflector and a cross-dipole inside the pot acting as the antenna.

The antenna is placed at a height of exactly 1/4 wavelength from the base of the pot, and the cross dipole wire lengths are 0.52 and 0.42 wavelengths long. They are different wavelengths as this achieves circular polarization. Adam writes that the gain should be about 4 – 5 dB’s better than a patch antenna.

The first video shows the performance of the antenna in SDR# when receiving the Outernet and Inmarsat/Alphasat L-band satellite signals indoors. Together with an LNA4ALL and RTL-SDR, Adam gets about 8 dB on the Outernet signal and 24 dB on AERO.

The post A Cooking Pot L-Band Antenna appeared first on rtl-sdr.com.

Outernet is an L-band satellite service that aims to be a “library in the sky”. They are constantly transmitting data such as up to date news, weather updates, Wikipedia pages, books, ISS APRS repeats and much more. Their DIY receiver kit consists of a lithium battery pack, L-band patch satellite antenna, LNA with built in filter, C.H.I.P mini Linux computer and an RTL-SDR E4000 or V3.

The DIY kit is normally priced at $99 USD, but right now they are running a 30% off Christmas promotion, bringing the price down to $69.30 USD. If you don’t need the battery pack, the sale price is then only $55.30 USD. This seems like a very good deal as normally just the patch antenna and Outernet LNA would be almost $50 USD in total.

To get the discount you must purchase directly from their store and use the coupon 30OFF. The promotion ends 31 December 2016 at 11:59 PM CST so get in quick.

The post 30% Off Outernet L-Band RTL-SDR DIY Kits – $70 for RTL-SDR, LNA, Antenna, CHIP and Battery appeared first on rtl-sdr.com.

In previous posts we showed how Phillip Hahn had been trying to use his RTL-SDR as a GPS receiver on a high powered rocket in order to overcome the COCOM limits which prevent commercial GPS devices from operating when moving faster than 1,900 kmph/1,200 mph and/or higher than 18,000 m/59,000 ft.

In order to test future flights with the RTL-SDR GPS receiver, Phillip has been simulating GPS rocket trajectory signals and using his LimeSDR. The RTL-SDR then receives the simulated GPS signals which are then fed into SoftGNSS for decoding. The simulation simulates the Japanese SS-520-4 rocket which is a 32′ long, 2′ diameter small high powered rocket capable of putting loads like cubesats into orbit affordably. Using the simulated data Phillip is able to calculate the trajectory and see all the motor burns in the velocity profile.

While Phillip intends to use the RTL-SDR on a similar rocket in the future, he notes that the simulation does not take into account problems such as thermal noise, or RF interference, rocket jerk, satellite occlusion and vibration problems.

The post Simulating GPS with LimeSDR and Receiving it with an RTL-SDR appeared first on rtl-sdr.com.

Vivaldi’s are linearly polarized broadband antennas that have a directional radiation pattern at higher frequencies. The high end SDR manufacturer RF Space produces their own Vivaldi antennas made from PCB boards which they sell online. The larger the antenna, the lower its receiving frequency, and ones that go down to about 200 MHz are almost the size of a full adult person. But all sizes receive up to 6 GHz maximum. Typically smaller versions of Vivald antennas have been used in the past for L-Band satellite reception.

Over on his blog KD0CQ noted that he always had trouble trying to purchase a Vivaldi from RF Space because they were too popular and always out of stock. So he decided to try and build his own out of PCB boards. On this page he’s collected a bunch of Vivaldi cutout or transfer images. On his second page he shows a Vivaldi antenna that he built out of PCB material, just by using scissors and semi-rigid coax. With the Vivaldi placed outdoors he’s been able to successfully receive and decode L-Band AERO on his Airspy Mini even without an LNA. 

KD0CQ writes that he’ll update his blog soon with more results.

The post Building a Wideband Vivaldi Antenna for SDR Use appeared first on rtl-sdr.com.

BY70-1 is a Chinese amateur Cubesat satellite which was recently launched on December 29, 2016. It is expected to stay in orbit for only 1 – 2 months due to a partial failure with the satellite releasing into an incorrect orbit. The purpose of the satellite is for education in schools and for amateur radio use. The receivable signals include an FM repeater and BPSK telemetry beacon both of which can be received at 436.2 MHz. The telemetry beacon is interesting because it also transmits images from an on board visible light camera. These signals can easily be received with an RTL-SDR or other SDR with an appropriate antenna.

Over on his blog Daneil Estevez has been posting about decoding these telemetry images. He’s been using telemetry data collected by other listeners, and the gr-satellites GNU Radio decoder which is capable of decoding the telemetry beacons on many amateur radio satellites. So far the decoded images haven’t been great, they’re just mostly black with nothing really discernible. Hopefully future decodes will show better images.

If you want to track the satellite and attempt a decode, the Satellite AR Android app has the satellite in its database.

Not many people seem to have gotten telemetry decodes or images yet, but below we show an image decoded by @bg2bhc on Twitter.

The post Receiving the Recently Launched BY70-1 Satellite appeared first on rtl-sdr.com.

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.

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