Tagged: rtl2832u

Starlink Doppler Reflections Caught with an RTL-SDR

Over on YouTube William IU2EFA has been uploading multiple short "meteor scatter" videos. This involves using an RTL-SDR to briefly receive distant radio stations via the RF signal reflecting off the ionized trail left by meteors entering the atmosphere. However, in a similar fashion satellites orbiting the earth can also reflect distant radio stations. 

In one of his latest videos William caught a train of Starlink satellites reflecting the signal from the Graves radar in France. To do this he uses a 10 element VHF Yagi, and an RTL-SDR running with HDSDR and SpectrumLab. In the video you can see and hear the change in frequency caused by the doppler shift.

Starlink is a SpaceX project aiming to bring ubiquitous satellite internet to the entire world. Currently 358 Starlink satellites are in orbit, and the end goal is to have 12000.

IU2EFA Starlink radar Graves doppler reflection

A Homemade Boat Computer with RTL-SDR for Weather Fax, NavTex and more

Over on Hackaday we've seen a post about [mgrouch]'s "boat computer" which consists of a Raspberry Pi 4, HDMI display, and a whole slew of sensors and receivers useful for a marine environment including an RTL-SDR.

The built in equipment includes a GNSS receiver, orientation sensors, AIS receiver, 4G and WiFi, lightning EMI sensor and alarm, optional autopilot integration, rudder angle sensor, connections to boat instruments like wind, depth, speed, temperature, barometric and humidity sensors, an Iridium receiver, and finally an RTL-SDR for receiving weather fax, NavTex, satellite weather, AIS, RTL 433, morse code and more. It really is an "all-in-one" device.

His blog post explains in detail how each of the components work in the system, and in particular for the RTL-SDR he shows how you can use the boat computer to receive FM via GQRX, and NavTex via the Java based Frisnit Navtex decoder. Navtex is a marine radio service that transmits at 518 kHz or 490 kHz. It provides text data regarding weather forecasts, weather warnings, navigational information, and urgent maritime safety messages. For his antenna he writes that he uses a 10 kHz - 30 MHz Mini Whip antenna that he purchased on Aliexpress.

mgrouch's Boat Computer with RTL-SDR
mgrouch's Boat Computer with RTL-SDR

Creating an APRS I-Gate and Digipeater with Baofeng and RTL-SDR

Over on YouTube ModernHam has uploaded a video showing how to create an APRS I-Gate and Digipeater with Baofeng and RTL-SDR. He also makes use of a Raspberry Pi as the computing module and an audio cable to connect the Baofeng to the audio jack of the Pi. The tutorial then consists of a walk through of the various software setup steps, and finally how to connect the Baofeng and RTL-SDR to the Pi.

If you weren't already aware, Automatic Packet Reporting System (APRS) is a digital VHF mode used in amateur radio. It allows for packets of data to be sent to receiving nodes over a local area via RF. Typical uses for it are vehicle tracking, weather station telemetry, text messages, announcements and other wireless device telemetry like high altitude balloons. An I-Gate is an internet connected node which receives local APRS RF signals and uploads them to the internet, to be seen on sites like aprs.fi. TX capable I-Gates may also broadcast to the local RF network messages from APRS transmitters on the other side of the world.

APRS I-Gate and Digipeater with Baofeng and RTL-SDR

DragonOS: Debian Linux with Preinstalled Open Source SDR Software

Thank you to Aaron for submitting news about his latest project called "DragonOS" which he's been working on while in COVID-19 lock down. DragonOS is a Debian Linux based operating system which comes with many open source software defined radio programs pre-installed. It supports SDRs like the RTL-SDR, HackRF and LimeSDR.

Aaron's video below shows how to set up DragonOS in a VirtualBox, and he has two other videos on his channel showing how to set up ADS-B reception with Kismet, and how to run GR-RDS in GNURadio. He aims to continue with more tutorial videos that make use of the software installed on DragonOS in the near future.

DragonOS 10 Installer (download in description)

Screenshot of the GR-RDS Tutorial

RTL-SDR AIS Android App Now with Waterfall Display for Frequency Offset Tuning

Thank you to Christian, author of the RTL-SDR AIS Android App for letting us know that he's updated his app and it now includes a waterfall display for tuning the AIS frequency. Tuning the AIS frequency is not required on higher end RTL-SDR dongles that come with a TCXO (Temperature Compensated Oscillator), but cheaper RTL-SDRs will have significant frequency offsets that will require the offset to be determined after a few minutes of warm up time. The easiest way to do this is with a waterfall display as that allows you to tune the frequency manually.

AIS stands for Automatic Identification System and is used by ships to broadcast their GPS locations in order to help avoid collisions and aide with rescues. An RTL-SDR with the right software can be used to receive and decode these signals, and plot ship positions on a map.

RTL SDR AIS Driver App PPM

UFO Tracking Network using RTL-SDRs to Rule out False Positives from Commercial Aircraft

The Unidentified Aerial Phenomenon Tracking Network (UAPTN) is an effort to set up crowd sourced Raspberry Pi powered cameras all over the world in order to record videos of "unidentified aerial phenomena" AKA UFOs. In order to rule out false positives from known aircraft, they are recommending that contributors install a FlightAware RTL-SDR in their system for aircraft tracking. 

For this purpose doing your own ADS-B flight tracking would be required as most commercial flight tracking sites censor military and private jets. The only site that does not censor data is ADS-B Exchange. However, of course military aircraft conducting operations are always able to turn ADS-B off if required for the mission which is what the UAP network will probably detect the most. 

If UFO tracking does not interest you, then you might instead be interested in creating a RTL-SDR based GhostBox to talk to spirits!

Techminds Reviews the Ham-It-Up Nano Upconverter

A few days ago we posted about the release of the new NooElec Ham-It-Up Nano upconverter which sells for US$49.95 on their store and Amazon. Upconverters enable SDRs that cannot tune in the HF bands to receive HF by shifting the low HF frequencies "up" into a range receivable by most VHF/UHF capable SDRs.

In his latest video Techminds reviews the Nano together with an E4000 tuner based RTL-SDR with built in bias tee. In the video he demonstrates it working with the SDR# software, and shows how to set the Shift parameter to ensure that the correct frequency offset it set. He goes on to demonstrate reception through the various HF bands confirming that the unit works as expected.

Nooelec Ham It Up NANO - HF Upconverter

Coronavirus: Hamvention Cancelled & Other Updates

Hamvention, the largest yearly amateur radio event has been cancelled this year due to concerns over the spread of the Coronavirus (COVID-19). It was due to be held during May 15 - May 18, 2020. Chairman Jack Gerbs writes:

The Hamvention Executive Committee has been monitoring the COVID19 pandemic. We have worked very closely with our local and state health Departments.

It is with a very heavy heart the Hamvention Executive Committee has decided to cancel Hamvention for this year.
This decision is extremely difficult for us but with around two months until the Great Gathering we felt this action necessary.
More specific details regarding the closure will soon be posted here.

Thank you for your understanding in this time of International Crisis.

Jack Gerbs
General Chairman HV2020
[email protected]

According to the ARRL cancelled events tracker, a number of other amateur radio events across the USA have also been cancelled, and we're seeing similar reports for most other countries too. At this stage we expect that most events will be cancelled over the next few months.

RTL-SDR Blog V3 Stock & Shipments

Due to manufacturing delays and slowdowns related to the Coronavirus our multipurpose dipole antenna set, and set including antenna and dongle is currently out of stock on our international webstore. We expect to be able to restock by the end of the month. There remains sufficient stock of the dongle itself. Our wideband LNA will also be back in stock next month.

Amazon USA is still stocked with all products, however there may be a short out of stock period within 1-2 weeks as we await for the arrival of replenishing stock in the USA.

In regards to international shipments please expect that there could be delays. At the moment we are seeing most mail still getting through in a timely manner, however this could change over the coming weeks as more travel restrictions come into play.

It is expected that other radio related products could also soon be out of stock, or delayed due to the situation.

Other Coronavirus Posts

N0SSC has provided a good post outlining the risks to the amateur radio population and why amateur radio event cancellations are a good idea. 

SolderSmoke, a popular podcast about radio homebrewers has put out a special Coronavirus crisis podcast.

We thought it would be nice to put out a special edition of the podcast to help listeners keep up their morale during this difficult time. So we’ll do our regular kind of show, but we’ll try to emphasize things you can do to stay busy and keep up morale while stuck at home.

Over on The SWLing Blog Thomas has put out a post about social distancing and how to keep occupied without leaving the house, and another post about how shortwave broadcasters are now adding regular Coronavirus information and news to their broadcasts.