SDRA2020 Online Conference Videos

The Software Defined Radio Academy is an organization that holds a conference within the yearly HAMRADIO fair in Friedrichshafen, Germany. This year due to the pandemic the conference was held online, and recently videos from the various talks have begun to slowly get uploaded to their YouTube channel.

The talks are typically very technical in nature, but if you're interested in cutting edge SDR research and applications then these are good talks to get caught up on. Currently there are seven videos that have been uploaded, but we are expecting that there are more to come since there are more talks listed in their programme. They appear to be uploading one video per day at the moment so get subscribed to their YouTube channel for the upcoming videos.

The currently uploaded talks include:

  • A Keynote interview with N1UL Dr. Ulrich Rohde
  • Laurence Barker G8NJJ: Using Xilinx Vivado for SDR Development
  • Edwin Richter DC9OE, Crt Valentincic S56GYK: Usage of higher order Nyquist Zones with Direct Sampling Devices
  • Prof. Dr. Michael Hartje DK5HH: Signalprocessing in the man made noise measurement system ENAMS
  • Bart Somers PE1RIK: Long term spectrum monitoring using GNUradio and Python

We are looking forward to the upcoming talks like the one by Dr. Bastian Bloessl DF1BBL that discusses the GNU Radio on Android implementation.

SDRA2020 - 02 - N1UL: Interview with Dr. U. Rohde

Characterizing Yagi Antenna Directionality via ADS-B Reception

Over on his blog Alex Krotz has been investigating whether adding more passive director elements actually affects the directionality of his home made Yagi-Uda antenna. Instead of using modelling software, Alex wanted a more accurate result that took into account all the imperfections of his antenna.

His idea was to receive ADS-B signals with his Yagi and a dipole antenna, then compare the data received in order to determine in which directions the Yagi receives better than the dipole. To do this he first creates a standard 2D map of plane tracks collected over a 24hr period for both the dipole and Yagi. A gaussian blur is applied to the two maps in order to fill in blank space and the data is normalized. Then he simply subtracts the dipole plot from the Yagi-Uda plot. The resulting difference plot reveals a mapping of where the Yagi receives better or worse compared to the dipole in a 2D plane.

Directivity of the Yagi revealed by comparing against a dipole
Directivity of the Yagi revealed by comparing against a dipole

TechMinds: How to Track Weather Balloons Using SDR

In his latest video Tech Minds has uploaded a video showing how to use an SDR to receive transmissions from radiosondes carried by weather balloons. Every day meteorological agencies around the world launch weather balloons several times a day. Each balloon carries a device called a radiosonde which continuously transmits weather telemetry to a ground station. With an SDR, antenna and free software it's possible to decode these radiosonde signals yourself from home.

In the video Tech Minds uses an RSPdx, SDRuno, VBCable and the RS41 Tracker software to receive telemetry from an RS-41 radiosonde launched in his area. We note that an RTL-SDR and SDR# could also be used. He shows the various bits of weather information available from the telemetry including information like temperature, pressure, humidity and the dew point. GPS and hardware status data is also available. Finally he shows how to view the balloon's flight path in Google Earth.

How To Track Weather Balloons Using SDR

Metal Case Upgrade for the SDRplay RSP1A back in Stock

Our metal case upgrade kit for the SDRplay RSP1A software defined radio is now back in stock in our store and will be ready to ship out within the next couple of days. This is a premium aluminum metal upgrade enclosure for the SDRplay RSP1A. Helps block RF interference and protects the RSP inside the sturdy enclosure. This will be the final batch made of this product, so if you are interested please order before stock runs out for good.

The kit includes 1x black aluminum metal enclosure with two labelled side panels, 1x black semi-hardshell carry case, 1x thermal pad to keep the RSP1A cool and mechanically stable inside the enclosure, 1x accessory set including enclosure screws, GND lug bolt set and 3M anti-slip rubber feet.

RSP1A Metal Case Upgrade
RSP1A Metal Case Upgrade

NanoVNA V2 Video Tutorials

The NanoVNA V2 (aka S-A-A-2) is a vector network analyzer (VNA) with 50 kHz to 3 GHz frequency range. Recently is has become readily available for around $60 + shipping from the Tindie store. We like this product a lot and are planning to get some for our store soon as well. (Update: A limited quantity of NanoVNA V2's are now available in our store)

A Vector Network Analyzer (VNA) is an extremely useful tool for radio hobbyists as it allows you to measure and tune antennas and filters, as well as measure cable loss among other applications. Until recently low cost VNA's cost hundreds of dollars. Then came along the original NanoVNA which brought expensive VNA capabilities to the masses with its low $40 pricing. But the original design is limited to a maximum frequency of only 900 MHz. The new V2 design pushes this maximum frequency up to 3 GHz officially, and unofficially up to 4.4 GHz with reduced performance. It also improves on overall dynamic range and maintains the affordable sub $100 price. We note that the NanoVNA V2 is unrelated to the original NanoVNA apart from being the inspiration, and sharing the same firmware base.

Over on YouTube Robert J. Meade has been uploading a series of videos demonstrating and teaching viewers how to use the NanoVNA V2 to measure various devices. For example in his videos he shows how to use the NanoVNA V2 to measure one of our RTL-SDR Blog Broadcast FM filters, how to measure a log spiral & clover antenna, use measurements to rebuild a variable attenuator, measure an active device (SAWbird+ NOAA), and how to measure a DIY microstrip L-band LNA. If you're just getting started with the NanoVNA V2, then these are some great videos to start with.

NanoVNA V2: RTL-SDR.com FM Bandstop Filter Measurements via NanoVNA-QT

Hak5: Turning a Key Croc into an RTL-SDR Server

The Hak5 Key Croc is a pentesting tool designed for emulating USB devices such as keyboards. It is commonly used by pentesters for keylogging and keystroke injection. It has some advanced features like keyword detection which can be used to detect when a certain word is typed. Under the hood it runs Linux on a quad-core ARM processor.

Over on the Hak5 YouTube channel Glytch shows us that he's been using the Key Croc as a remote RTL-SDR server. The server is setup through a payload script, which is then activated by typing "setup" into notepad on a PC. The keystroke logging and keyword detection feature detects the setup keyword, and runs the payload script which installs the RTL-SDR drivers and rtl_tcp server all while using the keystroke injection feature to output the install progress. Then it is a simple matter of plugging in an RTL-SDR, and connecting to the rtl_tcp server on a program like SDR#. 

Glytch notes that this is useful because you can run the entire Key Croc server and RTL-SDR on a portable battery pack, and now you have a remote SDR that you can place anywhere within your WiFi network.

Turning a KeyCroc into an RTL SDR Server w/ Glytch

DragonOS: Decoding Iridium Satellites with the Iridium Toolkit and an RTL-SDR

DragonOS is a ready to use Linux OS image that includes various SDR programs preinstalled and ready to use. The creator Aaron also runs a YouTube channel that has multiple tutorial videos demonstrating software built into DragonOS.

In his latest video Aaron explores Iridium reception with an RTL-SDR Blog V3, RTL-SDR Blog Active L-Band Patch Antenna and Iridium Toolkit/gr-iridium. Iridium is a satellite constellation that provides services such as global paging, satellite phones, tracking and fleet management services, as well as services for emergency, aircraft, maritime and covert operations too.

In the video he shows how to edit the config file to turn the bias tee on, how to record Iridium data, how to install the AMBE voice decoder, and finally how to decode the Iridum data with Iridium toolkit and play voice recordings.

DragonOS LTS Decoding Iridium satellites with the Iridium toolkit (gr-iridium, RTL-SDR)

Tech Minds: Testing the Mayhem Firmware on the HackRF Portapack

In a video uploaded to YouTube last week, Tech Minds explored the HackRF Portapack, which is an add on for the HackRF SDR that allows the HackRF to be used portably without a PC. In that video he demonstrated it running the stock firmware.

In his latest video Tech Minds explores the Mayhem firmware, which is firmware developed by a third party in order to add significantly more features. The Mayhem firmware is a fork of the Havok firmware which is no longer maintained. If you're interested, back in 2018 we did our own review of the Havok firmware.

In the video Tech Minds first explains how to install the Mayhem firmware which also requires you to add an external SD card into your portapack. He goes on to demonstrate the various RX decoders available including ADS-B, ACARS, AIS, AFSK, BTLE, FM/AM/SSB audio, analog TV, ERT meters, POCSAG, Radiosonde and TPMS. Next he shows the various transmittable signals available including, ADS-B, APRS, BHT, GPS Sim, Jammer, Key Fob, LGE, Mic, Morse, Burger Pagers, OOK, POCSAG, RDS, Sounds, SSTV, TEDI/LCR and TouchTune.

MAYHEM Firmware for the HackRF Portapack Installation / Overview