Upcoming DEFCON Cyberspectrum Wireless Village SDR Talks

At this years DEFCON conference SDR evangelist Balint Seeber will be hosting Cyberspectrum #23. DEFCON is a yearly conference with a focus on hacker topics, which often include SDRs and other radio topics too. This years conference will be help on August 9 - 12 a Caesars Palace & Flamingo in Las Vegas. Cyberspectrum is an almost monthly meetup of SDR enthusiasts and researchers that is normally held in the San Francisco Bay Area, but often hosts remote speakers via teleconference. This months meetup will be held at DEFCON on August 9, hosted by the Wireless Village.

The planned talk overviews are listed below, and Balint would like to note that any physical attendees are welcome to get in contact with him and submit more talks. Previous Cyberspectrum talks can be viewed on this YouTube playlist.

Michelle Thompson (@abraxas3d): "ORI and Phase 4 Ground" (https://phase4ground.github.io/)

Open Research Institute (ORI) is a new non-profit research and development organization which provides all of its work to the general public under the principles of Open Source and Open Access to Research.

One of our projects is called Phase 4 Ground. Our mission is to provide an open source implementation of DVB-S2 and DVB-S2X for both satellite and terrestrial amateur radio use. Phase 4 Ground radio system has a 5GHz uplink and a 10GHz downlink. We are developing SDR software that heavily leverages IP multicast and RTP protocols to set up and tear down distributed remote radio functions.

The reference designs are in GNU Radio and we will provide recipes for as many SDRs as possible.

Phase 4 Ground radios are intended to be reusable and reconfigurable, supporting payloads at GEO (AMSAT Phase 4B), HEO (AMSAT Phase 3E), and beyond (such as NASA's Cube Quest Challenge). Additionally, our radios will work as terrestrial microwave stations. These 'Groundsats' on mountaintops or towers establish a fun and flexible digital microwave experience. If you want to build up your radio from SDRs, you can. If you want to build it entirely from scratch, then you can. Our manufacturing partner for an off-the-shelf design is Flex Radio.

Lucas Teske (@lucasteske): SegDSP SpyServer Segment Digital Signal Processor

SegDSP is a WIP "Segment Digital Signal Processor" that is tuned for connecting into a SPY Server and do automatically demodulation/recording/parsing of RF data. This talk will be about what it does today, how was the development, how it works, how it will work and what are the uses for it. Tired of losing the pass of a LEO satellite? Want to hear the recording from last week? SegDSP is a Open Source tool made in Go for both learning and monitoring Satcom and Terrestrial Com.

Luigi Freitas (@luigifcruz): "Reverse Engineering X-Band Satellites Datalink And The Worst Software Defined Radio Ever"

This talk will be about the reverse engineering process of the next generation X-Band datalink signal on-board of Sun Synchronous Satellites like Suomi (NPP) and NOAA-20 (NPOESS/JPSS-1). From the RAW I/Q recording to the decompressed high-resolution Earth pictures. This is the latest addition to the Open Satellite Project, a non-profit organization that is committed to develop and publish software tools and hardware projects that enable the Open-Source Community to access spacecraft non-sensitive data.

The other half (or so) of this talk will be about the “Worst SDR Ever” that is made entirely of dirty cheap parts readily available from China. This project is intended to demonstrate how a Software Defined Radio works utilizing real hardware and comprehensive modular software.

Gavin Rozzi (@gavroz): "OC Radio Live" (https://ocradio.live)

An online trunking scanner website with time shifting capabilities covering New Jersey powered by the RTLSDR and open source software.

Using RPiTX as a 2FSK Transmitter

Over on his blog, Rowetel has been experimenting with 2FSK transmissions and the new v2beta branch of RPiTX. RPiTX is a piece of software for the Raspberry Pi that enables it to transmit RF signals via a GPIO port, with no other hardware required.

In his tests he's been creating 100bit/s 2FSK test frames, transmitting them at 7.177 MHz, and receiving and decoding them on another PC with a hardware radio. The results show that the transmission is working perfectly, with only minor artefacts caused by RPiTX. Rowetel also notes that the narrow band spectral purity of the RPiTX output is remarkably clean. The only worry is the wide band harmonics which can easily be removed with filtering.

This shows that RPiTX could easily be used as a transmitter for amateur radio purposes, assuming proper external filtering is applied. Rowetel also mentions that he hopes that cheap radio technologies like RPiTX could one day be used to help reduce the cost and difficulty in covering the 'last 100 miles' of communications in the developing world.

RPiTX 2FSK apectrum analyzer measurement showing good narrow band spectral purity.
RPiTX 2FSK apectrum analyzer measurement showing good narrow band spectral purity.

SDR-Remote: A Physical Tuning and Control Knob for SDR#

Recently Maxim who runs his small company "ExpElectroLab" wrote in and wanted to share a new product that he's developed called "SDR-Remote v2.0". This is a physical tuning knob that connects to your PC, and can be used with programs like SDR#. Apart from the knob, there are also several buttons for volume control, presets, and various other functions. He writes:

Heart - ARDUINO NANO V3.0, buttons, encoder and software. Sketch wrote to order a professional programmer.

Implemented by:

  • tuning the reception frequency with a multiplicity of 1 kHz, 100 kHz, 1 mHz (additionally 50 Hz)
  • volume control
  • Mute the sound (mute)
  • FM mono / stereo switching
  • switching of modulation types
  • turn on / off the noise
  • adjustment of the threshold of noise
  • adjustment of the width of the strip
  • switching ranges 160m, 80m, 40m, 25m, 13m.10m, FM, AVIA, 2m, 70cm

It appears that Maxim doesn't have a full store, but rather sells the devices on VK Markets, which is a Russian clone of Facebook. Also at the moment only SDR-Remote V1.0 is available for sale, but V2.0 seems to be due to go on sale soon. Version 1.0 sells for 2,650 Rub, which is equivalent to around US$42. His store also contains various other home brew SDR related products such as upconverters, LNA's, filters and a fractal antenna. The video below in in Russian, but shows V2.0 being unboxed and demonstrates it working with SDR#.

Maxim has noted that you can contact him at [email protected] if you are non Russian and are interested in his products.

SDR-Remote V1.0
SDR-Remote V1.0

SDR-Remote V2.0 или валкодер для SDR Sharp

Building a Tracking Mount for HRPT Weather Satellite Reception

Over on YouTube channel The Thought Emporium recently released a new video where they show the first steps they've taken towards building a home made satellite tracking mount for receiving HRIT and HRPT low earth orbit weather satellites. In their build they use a 2.4 GHz WiFi parabolic grid antenna, gears and mounts made from milled wood, and some metal supports. The build is not yet finished, but they intend to show their progress in future videos. Note that we're not confident that the 2.4 GHz grid antenna will actually work for them. In the past people have had success with 1.9 GHz Grid antennas however.

If you didn't already know, receiving HRPT weather satellite signals is a little different to the more commonly received NOAA APT or Meteor M2 LRPT images which most readers may already be familiar with. HRPT is broadcast by the same NOAA satellites that provide the APT signal at 137 MHz, but is found in the L-band at around 1.7 GHz. The signal is much weaker, so a high gain dish antenna with motorized tracking mount, LNA and high bandwidth SDR like an Airspy is required. The payoff is that HRPT images are much higher in resolution compared to APT.

Actually, it's not entirely true that a tracking mount is required, although it certainly makes things easier. We've seen in the past that 'Tysonpower' was able to receive HRPT by tracking his dish by hand.

The Thought Emporium also note that they hope to use their tracking mount in the future for other purposes like amateur radio astronomy. In one of their previous experiments they've build a smaller version which was able to create a heat map of WiFi signal strengths in their area.

Building a Motorized Satellite Tracker for HRIT/HRPT Reception and Radio Astronomy - Part 1

Helium: The SDR Based Cryptocurrency for IoT

Helium is a cryptocurrency being designed for internet of things (IoT) sensors which will be based on low cost software defined radio (SDR) technology - that's a lot of buzzwords!. The idea is to design a system that will pay people to run an internet connected gateway which will receive data from wireless sensors, and put that data onto the internet. A use case that Helium has already developed is providing services to track and monitor medicine and food supplies. The linked article gives a good example of this use case:

...let’s say you have a gateway in your house: if a vial of medicine were to enter your coverage zone, it would send its location and temperature data to your gateway, which would then send it to its proper destination in return for a previously agreed upon cryptocurrency fee. These steps would then be cryptographically verified and recorded in the distributed ledger.

In terms of IoT network competition, LoraWan and SigFox IoT networks are already popular and established in several places in the world, but wireless coverage isn't great because these networks rely on companies to build gateway infrastructure. Helium crowd sources this infrastructure instead, which could result in greater coverage.

Most cryptocurrencies base the security of their network on the 'proof of work' process, which is a way to ensure that the miners get rewarded for the heavy cryptographic computations that they do in order to secure the network. Instead of proof of work, Heliums idea is to use a 'proof of coverage' system, where other gateways will confirm if a gateway is providing coverage and is in the correct location. Helium cryptocurrency 'miners' will be the people running the internet connected gateways, and they will be paid for any devices that use their wireless coverage.

According to one of their latest blog posts, the wireless gateway radio system is to be based on a software defined radio architecture. The reasoning behind using SDR is that they need to support potentially thousands of wireless sensor channels, require the sensors to be able to be geolocated, and require the radio to be low cost and energy efficient. For geolocation of sensors they are considering the use of radio direction finding techniques that we assume will be based on pseudo-doppler, or alternatively they will use the time difference of arrival (TDoA) technique which requires the signal to be received by multiple gateways. The SDR will be developed on a dual core TI SoC, with four programmable realtime units (PRU), which they'll use to interface with the RF chips.

At the moment Helium is just a whitepaper, and we haven't seen any concrete evidence of a working SDR design yet, but according to their website they plan to launch gateway hardware in Q4 2018 for a cost of $495. 

The Helium Network
The Helium Network

A Car Based SDR Station for ADS-B, ATCS, P25, DMR, POCSAG and more

Over on YouTube user Corrosive has uploaded a video where he takes us on a tour or his very nicely set up mobile SDR station that is built into his car. His setup includes several antennas on his car's roof which cover multiple bands, a BCD780XLT scanner, an RTL-SDR, an Android head unit that is capable of running multiple SDR apps and also a Windows tablet that is used to run more CPU heavy SDR apps.

Later in the video he shows himself running SDR Trunk on the tablet and receiving and decoding the local P25 police department signal, and then running dump1090 for monitoring aircraft ADS-B, and Gpredict for tracking satellites.

Corrosive's Mobile SDR Station | Receive ADS-B ATCS P25 DMR POCSAG and More on the Go!

RadCom Review of the RSPduo Now Available Online

In the July 2018 edition of the UK based amateur radio magazine 'RadCom' Mike Richards wrote up a review of the RSPduo. This review is now available for free to download from SDRplay (pdf). The RSPduo is the latest product from SDRplay. Unlike previous models the RSPduo has two tuners on board which can be used to tune to two independent 2 MHz wide areas of the spectrum simultaneously. It currently retails for US $279.95 + shipping.

Mike's review goes over the design of the RSPduo and discusses it's dual tuning capabilities. He mentions that the most exciting prospect of the RSPduo is going to be the phase-coherent applications, such as active noise cancelling. At the moment no software for these applications is available, however SDRplay is working on it. In addition to this, Mike also discusses the new API, changes to the filtering and connections, and well as some notes on sample rates and decimation.

Inside the RSPduo
Inside the RSPduo

Tutorial on using RS to Decode and Plot Radiosondes

A radiosonde is a small weather sensor package that is typically attached to a weather balloon. As it rises into the atmosphere it measures parameters such as temperature, humidity, pressure, GPS location etc, and transmits this data back down to a receiver base station using a radio signal.

Zilog's RS is a free open source radiosonde decoder for Linux and it supports a wide range of radiosonde protocols. Together with an RTL-SDR it is possible to receive radiosonde signals, and decode them using RS.

Over on his website, happysat has recently uploaded a tutorial that shows how to use RS with an RTL-SDR, CubicSDR or GQRX, and FoxtrotGPS, a GPS plotting program for visualizing the location of the radiosonde. The tutorial covers some tricky points like setting up audio piping in Linux, and getting the GPS data into a virtual COM port to use with FoxtrotGPS.

Alternatively, there are also Windows GUI based sonde decoders that can be used with the RTL-SDR such as SondeMonitor which costs 25 Euros, but also covers a wide range of sonde protocols, and RS41 Decoder which is a GUI for the RS41 sonde protocol only. If you are interested we have a tutorial on setting up radiosonde decoding in Windows with SondeMonitor available here.

Plotting the Sonde Location with an RTL-SDR, GQRX, RS and FoxtrotGPS.
Plotting the Sonde Location with an RTL-SDR, GQRX, RS and FoxtrotGPS.