Tagged: rtl2832u

A Hydrogen Line Radio Telescope made from a Homemade Helical Antenna and RTL-SDR

Thank you to Geoff for submitting his experience with creating a hydrogen line radio telescope out of an easy to build helical antenna, Raspberry Pi, LNA and an RTL-SDR. The Hydrogen Line is an observable increase in RF power at 1420.4058 MHz created by Hydrogen atoms. It is most easily detected by pointing a directional antenna towards the Milky Way as there are many more hydrogen atoms in our own galaxy. This effect can be used to measure the shape and other properties of our own galaxy.

Earlier in the year we uploaded a tutorial showing how to observe the Hydrogen line with a 2.4 GHz WiFi antenna. In Geoff's setup he used a home made Helical antenna instead. This antenna is basically a long tube with a spiral wire element wrapped around the tube. He also shows how he needed to impedance match the antenna with a triangular piece of copper tape. The result is a directional antenna with about 13 dBi gain. To complete his setup he used a NooElec SAWBird H1+ LNA/Filter, an RTL-SDR Blog V3 dongle and a Raspberry Pi.

The results show a clear increase in RF power at the Hydrogen line frequency when the antenna points at the Milky Way, indicating that the setup works as expected. It's good to see a Helical working for this, as it is fairly light weight and could easily be mounted on a motorized mount to scan the entire sky.

A Hydrogen Line Radio Telescope made with a Helical Antenna.
A Hydrogen Line Radio Telescope made with a Helical Antenna.

Russian YouTuber Compares the RTL-SDR Blog V3 against the ColibriNano on HF

Over on YouTube a Russian language channel called "HAM Radio Channel" has uploaded a video that compares our RTL-SDR Blog V3 against a ColibriNano. While the video is narrated in Russian, it is easy to understand the side by side comparisons with the V3 running on HDSDR on the left of the screen, and the ColibriNano running on its custom software on the right.

The Russian made ColibriNano is a 14-bit direct sampling SDR with 0.1-55 MHz tuning range (undersampling up to 500 MHz), and up to 3 MHz bandwidth. It costs about US$280 - US$300 depending on the region. The RTL-SDR Blog V3 is our US$24.95 receiver with built in direct sampling mod which allows users to bypass the tuner in software resulting in a low-end HF receiver.

While the RTL-SDR Blog V3 cannot compare spec-wise to the ColibriNano, the review shows that the 12x cheaper SDR can still hold up fairly well against the higher end product. Of course as we always say, the differences between most SDRs only become apparent in challenging signal conditions, and we're sure that the ColibriNano would win out in conditions with very strong and weak signals being received together without appropriate pre-filtering. But if the conditions and/or pre-filtering is right, we belive that the RTL-SDR Blog V3 is still the best bang for your buck overall.

Что лучше? RTL-SDR или ColibriNANO? Сравнение SDR приемников

Building a Raspberry Pi Based AIS Receiver with an RTL-SDR, Preamp and Collinear Antenna

Thank you to SARCNET (School Amateur Radio Club Network) for submitting news about their tutorial on building a Raspberry Pi and RTL-SDR based AIS receiver. In their tutorial they show what equipment is required and provide access to a ready to use SD Card image for the Pi that has the AIS software pre-installed and ready go. They also show how to upload data to various online AIS data aggregators like AISHub and MarineTraffic.

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.

The School Amateur Radio Club Network publishes a simple project aimed at promoting the deployment of maritime Automatic Information System (AIS) receiving stations around the world using cheap RTL-SDR dongles and Raspberry Pi computers. The purpose of the project is to improve the existing terrestrial AIS receiving network by encouraging enthusiasts to setup their own AIS receiving stations and to disseminate their local vessel traffic data freely to AIS Servers. This data can then be used by many organisations involved in monitoring and improving the safety and security of shipping.

The SARCNET project, which works on all models of Raspberry Pi, makes building the AIS receiving station simple by providing pictorial construction details with a pre-packaged Raspberry Pi image to download. The free project uses open-source software and a bootable Raspberry Pi image which has been updated to use the latest Raspbian Lite operating system.

One of the attractions of building your own AIS receiving station is that some AIS servers reward you when you freely upload your local vessel tracking data. They publish your station information, showing your station position on a map and your receiving statistics like messages per hour and coverage in nautical miles. Some give you free, premium access to their AIS data, which can be viewed on their mobile apps. Even so, by operating one of these AIS receiving stations, you will have the satisfaction of making the world a safer place.

AIS Received with a Raspberry Pi and RTL-SDR Dongle.
AIS Received with a Raspberry Pi and RTL-SDR Dongle.

PineTab Linux Tablet will have an Optional RTL-SDR Expansion Module

The PineTab is an upcoming $100 open source Ubuntu Linux Tablet being created by PINE who are known for their low cost Pine64 single board computers, Pinebook Laptop and Linux based PinePhone. The PineTab is not yet for sale, and they have just announced their intention to begin taking pre-orders in late May, and that the first production run will be a limited quantity pilot production intended only for early adopters.

What's interesting about the PineTab is that they are advertising that they are working on expansion options, with one expansion module being an RTL-SDR. It seems that the expansion module will allow cards to be inserted internally, keeping everything tidy on the outside. Apart from the RTL-SDR, they will also offer LoRa, LTE (with GPS) and sata SSD add on cards.

The standard specs of the PineTab are shown below:

  • Allwinner A64 Quad Core SOC with Mali 400 MP2 GPU
  • 2GB LPDDR3 RAM
  • 10″ MiPi 720p Capacitive LCD
  • Bootable Micro SD Slot
  • 64GB of eMMC
  • microHDMI port for external HD output
  • USB 2.0 A host
  • Micro USB 2.0 OTG
  • 2Mpx front-facing camera
  • 5Mpx rear camera
  • Optional M.2 slot
  • Speakers and Microphone
  • Volume rocker and ‘home’ button
  • Magnetically attached keyboard (optional)
  • 6000mAh battery 
  • 3.5″ Barrel Power (5V 3A) Port
  • Multiple expansion boards for LTE, LoRa and SATA SSD
 

Derpcon 2020 Talk: Breaking into the World of Software Defined Radio

Derpcon is a COVID-19 inspired information security conference that was held virtually between April 30 - May 1 2020. Recently the talks have been uploaded to their YouTube channel. One interesting SDR talk we've seen was by Kelly Albrink and it is titled "Ham Hacks: Breaking into the World of Software Defined Radio". The talk starts by giving a very clear introduction to software defined radio, and then moves on to more a complex topic where Kelly shows how to analyze and reverse engineer digital signals using a HackRF and Universal Radio Hacker.

RF Signals are basically magic. They unlock our cars, power our phones, and transmit our memes. You’re probably familiar with Wifi and Bluetooth, but what happens when you encounter a more obscure radio protocol? If you’re a hacker who has always been too afraid of RF protocols to try getting into SDRs, or you have a HackRF collecting dust in your closet, this talk will show you the ropes. This content is for penetration testers and security researchers to introduce you to finding, capturing, and reverse engineering RF signals. I’ll cover the basics of RF so you’re familiar with the terminology and concepts needed to navigate the wireless world. We’ll compare SDR hardware from the $20 RTLSDR all the way up to the higher end radios, so you get the equipment that you need without wasting money. I’ll introduce some of the software you’ll need to interact with and analyze RF signals. And then we’ll tie it all together with a step by step demonstration of locating, capturing, and reverse engineering a car key fob signal.

Ham Hacks: Breaking into the World of Software Defined Radio - Kelly Albrink

GNU Radio TEMPEST Implementation Now Available

TEMPEST refers to a technique that is used to eavesdrop on electronic equipment via their unintentional radio emissions (as well as via sounds and vibrations). All electronics emit some sort of unintentional RF signals, and by capturing and processing those signals some data can be recovered. For example the unintentional signals from a computer screen can be captured, and converted back into a live image of what the screen is displaying.

Until recently we have relied on an open source program by Martin Marinov called TempestSDR which has allowed RTL-SDR and other SDR owners perform interesting TEMPEST experiments with computer and TV monitors. We have a tutorial and demo on  TempestSDR available on a previous post of ours. However, TempestSDR has always been a little difficult to set up and use.

More recently a GNU Radio re-implementation of TempestSDR called gr-tempest has been released. Currently the implementation requires the older GNU Radio 3.7, but they note that a 3.8 compatible version is on the way.

The GNU Radio implementation is a good starting point for further experimentation, and we hope to see more developments in the future. They request that the GitHub repo be starred as it will help them get funding for future work on the project.

The creators have also released a video shown below that demonstrates the code with some recorded data. They have also released the recorded data, with links available on the GitHub. It's not clear which SDR they used, but we assume they used a wide bandwidth SDR as the recovered image is quite clear.

Examples using gr-tempest

GR-TEMPEST: GNU Radio TEMPEST Implementation
GR-TEMPEST: GNU Radio TEMPEST Implementation

RTL-SDR Blog V3 Units and Antennas Back in Stock at Amazon (Local US Stock)

Just a note that our RTL-SDR Blog V3 units and antennas are now back in stock at Amazon.com with local US stock. There were a few manufacturing and shipping delays related to COVID-19 so they had been out of stock for a couple of months. Currently they are being fulfilled via our partners based in Chicago, and all orders will ship out within 2-business days via USPS First Class. We will look at replenishing the the Amazon Prime warehouses in a few weeks and at the moment we are only shipping to US customers from Amazon. US customers can also order directly from our store at www.rtl-sdr.com/store and this will result in the shipping fee being waived.

If you are based elsewhere in the world, please order directly from our store at www.rtl-sdr.com/store which ships non-US orders direct from our warehouse in China. Alternatively some countries might benefit from our Aliexpress store, which can now utilize the reliable Aliexpress Standard Shipping line.

Our RTL-SDR Blog V3 is an improved RTL-SDR dongle. It includes features like a TCXO, SMA port, software switchable bias tee, built in HF direct sampling mod, aluminum enclosure, improved ESD protection, improved cooling via thermal pad and many other design improvements. The kit comes with a multipurpose dipole antenna which is extremely versatile. It can be used as a standard vertical dipole for terrestrial signals, or can be mounted horizontally in a V-Dipole configuration for NOAA/Meteor LEO weather satellites. It's also easy to mount outdoors through a window for best reception with two mounting solutions included. 

Amazon Links

RTL-SDR Blog V3 Dongle + Multi Purpose Dipole Antenna Set

RTL-SDR Blog V3 Dongle Only

Multi Purpose Dipole Antenna Set Only

RTL-SDR Blog Store

We are also shipping any US orders made from our Worldwide store via our local stock. If you order directly from us you can save $1.99 on shipping.

RTL-SDR Blog Store

Features of the RTL-SDR Blog V3.
Features of the RTL-SDR Blog V3.
The RTL-SDR Blog V3 Set. Includes RTL-SDR V3 dongle, and multipurpose dipole antenna kit.
The RTL-SDR Blog V3 Set. Includes RTL-SDR V3 dongle, and multipurpose dipole antenna kit.

Running rtl_tcp over the TOR Network

Over on his DragonOS YouTube tutorial channel Aaron has uploaded a video showing how it is possible to run rtl_tcp over the TOR network. TOR is an "anonymity network" which routes your internet traffic through thousands of volunteer nodes in order to make tracing your internet activity more difficult.

Aaron's tutorial shows how to route rtl_tcp traffic through a TOR connection on his Linux distribution DragonOS (although it should work on any Linux distro), and connect to it with GQRX.

However, a major caveat is that the data streaming result is rather poor with there being lots of data drops, probably due to the slowness of the TOR network. Perhaps running a smaller sample rate, or using a more efficient server like Spyserver might work better.  

DragonOS LTS Remote access RTL-SDR over TOR network (Gqrx, rtl_tcp, OpenWRT)