Category: Other

Working Towards a Fast OpenWebRX HF Web Receiver + The Ethics of KiwiSDR

Over on his blog András Retzler has created a post that discusses his research work on creating a fast networked wideband HF receiver. András is the creator of the web based OpenwebRX software, which allows RTL-SDR and some other SDR’s to efficiently broadcast their SDR data over a network and onto the internet. Some live SDR’s can be found at the OpenWebRX directory at sdr.hu.

The problem with the current implementation, András writes, is that while OpenWebRX works well with the RTL-SDR’s 2.4 MSPS sampling rate, it can not work so well with very high sampling rates, such as 60MSPS due to excessive computational requirements when several channels need to be monitored. András’ solution is to use his Fast Digital Down Conversion (FastDDC) algorithm which is significantly more CPU efficient. András writes that the FastDDC algorithm improves computation by up to 300% in some cases, can speed up calculations on low powered computers like the Raspberry Pi 2 and can be implemented on a GPGPU for even higher performance. He is still working to implement the algorithm in OpenWebRX.

Performance of the FastDDC Algorithm
Performance of the FastDDC Algorithm

In addition to his work, András has also posted about what he feels is a bit of an injustice between his work on OpenWebRX and the KiwiSDR designers. The KiwiSDR is a new wideband HF SDR that has recently been successfully funded on Kickstarter. Andras writes that he is discontented with the fact that the KiwiSDR developers have forked his open source software (OpenWebRX) and are now profiting from it, without contributing back to the original project.  András writes:

John Seamons has forked OpenWebRX, and sells his own hardware with it. The web interface is clearly the selling point of the device. After getting a lot of help from me, most of which was inevitable for his success, now John and ValentF(x) are leaving me with nothing, except a ‘Thank you!’. John has told me that OpenWebRX is a large part of his project, and he also claimed that my work has reduced the time-to-market of his product by maybe a year or so.

Why I’m standing up here is that forking open source software (which means changing the code in a way that is incompatible with the original version, and taking development in another direction), and funding it through Kickstarter is a very unusual way of getting things done. I acknowledge that John has very much work in his board and the accompanying software, however, he treated me and my project in an unethical manner.

In the Kickstarter comments section, the KiwiSDR creators reply back with their side. It is hard to say who is in the right in a situation like this. While what KiwiSDR have done is legal according to the licence, the ethics of doing so are questionable. We hope that both parties can successfully come to an agreement in the end.

If you want to directly support András and his work on OpenWebRX and other projects like FastDDC, then please consider donating to him at http://blog.sdr.hu/support. If you are a KiwiSDR backer, donating to Andras may be one way to right the situation if a deal cannot be reached.

Dave from EEVBlog Reviews the Red Pitaya

The Red Pitaya is a type of advanced digital acquisition device (DAQ) that is marketed mainly for use as a type of digital oscilloscope. But it has an on board programmable FPGA and through various downloadable apps can be used for many different applications, such as a spectrum analyzer, impedance analyzer, bode plotter, signal generator or even as a software defined radio. 

Back in February we posted how Pavel Demin had created an SDR app for the Red Pitaya which allows it to be used with common SDR software such as SDR# and HDSDR. The Red Pitaya has an on board 14-bit ADC which when in SDR mode can receive signals from between 0 to 50 MHz with a bandwidth of up to 2.5 MHz.

Recently, Dave from the hugely popular electronics YouTube show EEVBlog reviewed the Red Pitaya. Whilst Dave doesn’t try out the SDR apps, he tests it out as an oscilloscope and also tests more of its default apps such as the spectrum analyzer.

Unfortunately in his review the Red Pitaya does not seem to live up to expectations. During operation Dave encounters problems with the WiFi connectivity, frequent problems with the web based apps crashing and freezing on him, and discovers that the provided apps are extremely rudimentary and provide very little functionality. He mentions that the device is probably more useful for people wanting to write their own customs apps for specific applications, but as an out of the box digital measurement tool it is not there yet.

The Red Pitaya
The Red Pitaya

EEVblog #858 - Red Pitaya

SoDeRa: An upcoming low cost app-enabled open-source 100 kHz to 3.8 GHz SDR Transceiver

A new software defined radio called SoDeRa (SOftware DEfined RAdio) is currently under joint development by companies Canonical (the company behind the Ubuntu OS) and Lime Micro. SoDeRa is based on the new Lime Microsystems LMS7002M Transceiver chip which has a 100 kHz – 3.8 GHz range. The transceiver chip interfaces with an Altera Cyclone IV FPGA with 256 MB of RAM and a USB3 controller, and the whole radio will have 4x TX outputs and 6x RX inputs.

SoDeRa Block Diagram
SoDeRa Block Diagram

The people behind this SDR are currently marketing SoDeRa as “the Arduino of the Telecom and Radio Engineer”. It appears to be designed mainly to implement IoT and other radio communications protocols, but it also sounds like it could find excellent use in the hobby and amateur market as well as have benefits for the average person. Interestingly, the developers also plan to implement an app store which would allow you to essentially download a radio and instantly configure the SoDeRa SDR for any desired protocol or application. They write:

This is the first time that a revolutionary device for which we are organising a joint crowd-funding campaign with Lime Microsystems is made public. The #SoDeRa is the cheapest software defined radio you can buy. The #SoDeRa will have an app store and will be able to provide any type of (bi-directional) radio communication going from LTE, Lora, WiFi, GPS, Bluetooth, radar, radio-controlled toys/robots/drone, digital radio, digital TV to even MRI scanners, satellite and air traffic communications by just installing an app. The #SoDeRa is the Arduino of the Telecom and Radio Engineer.

The VP of IoT at Canonical also writes:

The SoDeRa is powerful enough to be a full MiMo LTE base station with long range coverage, provided you add the right antenna. You can via apps put other wireless communication protocols like LoRaWAN, Bluetooth, Zigbee, Z-Wave, GPS, Galileo, Airspace protocols, radar, MRI scanning RF, TV/Radio, any toy/robot/drone control, White Space, etc. But most importantly because of its price and ease of adding more protocols, the SoDeRa will enable anybody to define competing wireless communication protocols and put them into Github. Developers don’t like closed standards like LTE or complex standards like Bluetooth & Zigbee. The future will allow developers to compete against corporations and standardization bodies if they think current standards can be improved upon. The Internet has shown that this dynamic brought us easier standards through adoption like JSON and Yaml vs XML and EDI. Wireless, RF and telecom engineers never had an Arduino like the electronics engineers. The SoDeRa will plug this hole.

Development on SoDeRa is working towards a trend in radio systems where all radio devices are software defined, allowing for futuristic features like advanced spectrum control and the ability to change protocols on the fly. They write:

Including #SoDeRa in any type of smart device will greatly reduce the cost of deploying a mobile base station network because by open sourcing the hardware design it will become commodity. By including software defined radio in lots of devices, often with a completely different purpose, will allow these devices to become a smart cell via installing an extra app. In the future, support for software defined radio will likely be embedded directly in Intel and ARM chips. The foundational steps are already happening. This will likely reshape the telecom industry. Not only from a cost perspective but also from a perspective of who runs the network. Telecom operators that don’t deliver value will see their monopoly positions being put in danger. As soon as spectrum can be licensed on a per hour basis, just like any other resource in the cloud, any type of ad-hoc network can be setup. The question is not if but when. Open sourcing and crowdfunding will make that “when” be sooner than later. Smart operators that align with the innovators will win because they will get the app revenue, enormous cost reductions, sell surplus spectrum by the hour and lots of innovation. Other operators that don’t move or try to stop it will be disrupted. What do you want to be?

At first glance SoDeRa sounds like it will be an expensive device, but on their official website they are currently running a survey asking people what they would be willing to pay, and the lowest price given is $50 – $99. This makes it seem likely that in the future with enough volume SoDeRa could be sold at very low cost and become very popular.

I am willing to pay for 1 unit

  • $50 – $99 (lead time 9 months)
  • $100 – $199 (lead time 6 months)
  • $200 – $299 (lead time 3 months)
  • $300 – $399 (lead time 2 months)
  • $400 – $500 (lead time 1 month)

It sounds like the team behind SoDeRa are gearing up for a crowd funding campaign so we will be keeping an eye on this SDR.

Thanks to RTL-SDR.com reader Serdar (TA3AS) for submitting news about SoDeRa to us.

The SoDeRa SDR
The SoDeRa SDR
The SoDeRa PCB
The SoDeRa PCB

Red Pitaya and Software Defined Radio

The Red Pitaya is marketed as a type of digital oscilloscope, and is more accurately described as a type of digital measurement and control tool that sells for about $220 USD. However the technology behind its operation (high speed ADCs) is basically the same as what is used in a software defined radio like the RTL-SDR. By using the correct software, and by reconfiguring it’s onboard Xilinx FPGA, the Red Pitya can be turned into an SDR transceiver. 

Until recently SDR projects for the Red Pitaya have been rare and so Pavel Demin decided to create his own. So far he’s managed to create a dual channel SDR transceiver that is compatible with SDR#, HDSDR, GNU Radio as well as with HPSDR. It can tune from 0 – 50 MHz with a bandwidth of up to 500 kHz, sampling with its 14-bit ADC.

More information on setting the Red Pitaya up as a SDR transceiver with software like SDR# and HDSDR can be found on Pavels website.

The Red Pitaya
The Red Pitaya

Competition Winners Announced!

Firstly, thanks to all who entered our competition. We saw a huge response and learned a great deal about what the RTL-SDR community is up to these days. I encourage everyone to take a look through the comments on the competition post if you’re looking for project inspiration.

We ran competitions on Twitter, Facebook, the competition post itself and on our mailing list. We randomly chose 5 winners from each competition and will be sending them each one of our RTL-SDR Blog dongles. The 20 winners have now been selected. If you missed out, don’t worry – we hope to do more competitions like this again this year!

Facebook Winners!

Winners, please check your Facebook private messages. If you don’t see it, the message may be hidden in the spam inbox.

Zim Zimmerman – Currently working hard to overcome the NOISE related to living in an apartment complex in a Seattle suburb! TWO band pass filters; shielding via Al foil wrap and a directional antenna have helped. As hams say; “Good luck in the contest OM!” 73 K4IES

Sammy Truong – Exploring quickpass highway toll system.

Jimmy Vance – Just getting started with SDR dongles. For now will use them as general purpose receivers and spectrum analyzers

Amy Cstar – I’m a newbie and I’m hoping to use this to listen to the ISS 

Cezar Lesanu – Already running a radio meteor detection setup on RMOB and frequency stability and shielding are issues:http://www.rmob.org/livedata/main.php#Cezar Lesanu_ROAN@USV

Twitter Winners!

Winners, we’ve publicly tweeted you asking you to please email us directly. Please also tweet back at us confirming that you’ve received our notification.

Xizt ‏@RECEPTORR – Will use RTL-SDR dongle for learning wide band signals and monitoring Ham radio bands.

Rooster Mcdoogle ‏@RoosterMcdoogle – My first SDR project is going to be identifying/decoding local signals, and then satellites.

Sparkie Nelson ‏@SparkieNelson – Need a cheap spectrum analyzer for balloon beacon transmitter development.

DPini ‏@DPini – Right now, I’m trying to build a QFH antenna. My intention is to recieve NOAA and CubeSats

D M Miller ‏@bentmg – Hoping to set up a dedicated sdr to decode some DMR and NXDN signals in my area for streaming if I win the giveaway!

Blog Comment Winners!

We’ve emailed all blog comment winners using the email address that was provided. Please check your spam folder if you don’t see it, or contact us directly.

Jeff – Portable rf spectrum analysis

Stephen McBain – Starting out at the basics and using a dongle to decode different signals and just learning radio.

Matt – I’m working on building a WebSDR in Bucharest with full coverage from ~15mhz to ~1700mhz (R820T2 upper limit)

John Wilkerson – I use dual dongles for monitoring p25 trunked systems, as well as aircraft tracking.

Bryan – I’m pairing the RTL-SDR with my TS-940SAT and DXLab Commander + SDR# FTW.

Mailing List Winners! (Emails obscured for privacy)

We’ve obscured the winning emails for privacy, but we’ve emailed these winners now. Please check your spam inbox too!

g___e__e.r_i___i@____.com

j____p__a@____.com

v___o_t@________.ca

m_r___n@________.net

d_b___l_+_t_s_r@_____.com

Reverse Engineering Cheap Chinese Radio Firmware

This post isn’t related to SDR, however it may interest many readers as it has the potential to become the “RTL-SDR” of handheld hardware radios. Recently at Shmoocon 2016 (a yearly hacking and security themed conference), hardware hacker Travis Goodspeed showed how he was able to reverse engineer the firmware of a cheap Chinese made Tytera MD380 DMR digital handheld radio transceiver.

The reverse engineering feat essentially means that custom firmware can now be written to the radio. They’ve already managed to add a promiscuity mode that allows the radio to be able to receive from all talk groups on a known repeater and timeslot. Access to he firmware now also means that custom decoders for protocols such as P25, D-Star or System Fusion can potentially be added to the radio’s features in the future. In the end this could turn this cheap $140 radio into a more featured radio that would be worth much more.

See the full story over at Hackaday and the white paper here (start at page 76) and the video of the talk below.

Jailbreaking a Digital Two Way Radio Travis Goodspeed travisgoodspeed

Inside the Tytera MD380
Inside the Tytera MD380

PiTX QRP TX Shield for WSPR on 20M Now For Sale

Back in October 2015 we posted about a piece of software for the Raspberry Pi called PiTX. PiTX allows you to turn your Raspberry Pi into a fully functional RF transmitter. When combined with an RTL-SDR a full transceiver radio can be built using the QTCSDR software.

PiTX works by modulating the GPIO pins on the Pi in such a way that it is able to produce FM modulation. The major problem with using this method of producing radio is that it creates large amounts of harmonics and interference outside of the intended transmit frequency. Interference like this is illegal and could potentially disrupt life critical radio systems such as emergency services, cellphones and air traffic control.

In order to cleanly transmit with PiTX an output RF filter should be used. Recently, the team over at TAPR.org have released a 20M WSPR TX filter shield. WSPR is pronounced “Whisper” and is short for “Weak Signal Propagation Reporter Network“. It is a type of amateur radio signal that can be broadcast and received around the world by using very low transmit power. Radio amateurs use it to see how far their signal can travel when using very low power (QRP) and to investigate signal propagation conditions. 

The 20M WSPR shield sells for $20 at www.tapr.org/kits_20M-wspr-pi.html.

The WSPR shield sitting on top of a Raspberry Pi.
The WSPR shield sitting on top of a Raspberry Pi.

Demonstrating the ARM Radio

Back in November 2015 we posted about the ARM Radio, a minimalist direct sampling software defined radio that runs almost entirely on an ARM processor on a STM32F429 discovery board. It can tune from about 8 kHz up to 900 kHz, which covers the VLF, LF and some of the MF bands. 

Now over on YouTube amateur radio hobbyist W9RAN has uploaded a video where he demonstrates an ARM Radio that he built. He shows the radio in operation with it clearly receiving some NDB’s and some AM broadcast stations.

ARM Radio demo BY W9RAN