The latest RTL-SDR receiver from Thumbnet, the Thumbnet N3 is now shipping out. Back in October we received a sample of one of their prototypes and found it to have a very low noise floor since they have replaced the 1.2v switching regulator with a linear regulator.
ThumbNet is a company that is hoping to provide low cost satellite deployments, and make use of volunteers around the world with RTL-SDR’s to help track them. The RTL-SDR’s and antenna kits are provided to schools and educational institutions for free by ThumbNet, in exchange for students setting up and monitoring a satellite tracking station.
In their release email they wrote:
ThumbNet would like to send a very large “Thank You!!” to all of you who have supported us by purchasing one of our surplus N3 SDR receivers, and we wanted to take a second and let you know that we’re excited to announce that the N3’s have left the factory and will begin shipping.
The support has been tremendous and we have a backlog of many hundreds of receivers to get out. We will be working extremely hard, over the coming days to get them all delivered as quickly as possible (Orders will be shipped in the order they were received.).
Don’t forget that there are accessories in the ThumbSat Store (http://www.thumbsat.com/thumbnet-sdr-hardware/thumbsat-store-4 ) that may be of value to you, such as adapters, cables or power supplies to let you get the maximum performance from your ThumbNet N3.
A handful of independent tests have been done on the Qualification Models of the N3, and the results have been quite positive. If interested, you can read some of the reviews at the following links.
A new beta version of HDSDR has recently been released. HDSDR hasn’t been updated since 2013, so it is good to see that the author is back in action. HDSDR is a free general purpose SDR receiver, similar in nature to other programs like SDR# and SDR-Console. It was one of the first programs to work with the RTL-SDR dongle and despite a lack of recent updates is still a very solid piece of software.
The new HDSDR is version 2.75 Beta1 and the changes include:
more recording options
support for 8bit sampling format
HDSDR runs without output soundcard
support for 8k display resolution (7680×4320)
extended ExtIO capabilities
many fixes and improvements
The main visual difference we’ve noticed so far is the addition of a text dBM meter under the S-Units meter. We also discovered some new color palettes.
HDSDR Beta running a new bright grayscale color palette.
Back in March of this year we posted about the release of the FlightAware "Pro Stick". The Pro Stick is FlightAware's ADS-B optimized RTL-SDR dongle. It uses a low noise figure LNA on the RF front end to reduce the system noise figure, thus improving the SNR at 1090 MHz. Because the added gain of the LNA can easily cause overload problems if there are other strong signals around, FlightAware recommend using one of their 1090 MHz ADS-B filters in front of the dongle to prevent overload.
FlightAware.com is a company that specializes in live air travel tracking. Most of their data comes from volunteers running RTL-SDR ADS-B receivers.
The new Pro Stick Plus RTL-SDR based ADS-B Receiver from FlightAware.
Over on their forums and on Amazon, they announced the device and specs. They wrote:
FlightAware is excited to announce the next evolution of USB SDR sticks for ADS-B reception! The new Pro Stick Plus USB SDR builds on the popular Pro Stick by adding a built-in 1090 MHz bandpass filter. The built-in filter allows for increased performance and range of reception by 10-20% for installations where filtering is beneficial. Areas with moderate RF noise, as is typically experienced in most urban areas, generally benefit from filtering. By integrating the filter into the SDR stick, we are able to reduce the total cost by more than 40% when compared to buying a Pro Stick and an external filter.
Specifications:
Filter: 1,075 MHz to 1,105 MHz pass band with insertion loss of 2.3 dB; 30 dB attenuation on other frequencies
Amp: 19 dB Integrated Amplifier which can increase your ADS-B range 20-100% more compared to dongles from other vendors which can increase range 10-20% over a Pro Stick in environments where filtering is beneficial
Native SMA connector
Supported by PiAware
R820T2 RTL2832U chips
USB powered, 5V @ 300mA
Note that this dongle is only for ADS-B at 1090 MHz, and not for 978 MHz UAT signals, as the filter will cut that frequency out.
Back in April, we did a review of the original Pro Stick. We found its performance on ADS-B reception to be excellent, but only when a filter was used. The low NF LNA theoretically improves the SNR of ADS-B signals by about 7-8 dB, but in reality there is too much gain causing signal overload everywhere, thus making reception impossible without the filter. Rural environments may not need a filter, but in a typical urban or city environment strong FM/TV/GSM/etc signals are abundant and these signals easily overloaded the Pro Stick when no filtering was used. This new Pro Stick Plus dongle completely solves that problem at a low cost with its built in filter.
Remember that if you are using a run of coax cable between the LNA and RTL-SDR, then it is more optimal to use an external LNA, like the LNA4ALL. Only an external LNA mounted near the antenna can help overcome coax, connector, filter and other losses as well as reducing the system noise figure. The FlightAware dongles are the optimal solution when they are mounted as close to the antenna as possible. This is usually the case when running the FlightAware feeder software on a Raspberry Pi.
We hope to soon review the Pro Stick Plus, however we assume it will operate nearly identically to the Pro Stick + FlightAware ADS-B filter combination.
The LimeSDR is a RX/TX capable SDR with a 100 kHz – 3.8 GHz frequency range, 12-bit ADC and 61.44 MHz bandwidth. Back in June 2016 they reached their $500,000 goal on the crowdfunding site crowdsupply. They are now gearing up to enter mass production the final product. Recently they released a production update which is quoted below.
Production Progress
Since the successful close of our funding campaign, We’ve been incredibly busy preparing to deliver LimeSDRs to all our backers. Just as we worked hard during the campaign – internally, with key partners, and with our fantastic beta testers in the community — creating a series of exciting demos, we continue to work to ensure backers will have a first-class experience upon receiving their hardware. In this update, we’ll review the state of the production schedule, hardware design, testing setup, documentation, app store, and more.
Production Schedule
To be upfront, our production schedule has slipped, but not by a lot. We discovered that some of the parts used in the original LimeSDR design have since entered end-of-life status, so we redesigned the board with replacement parts. In addition, we are still waiting on manufacturers for a few key components, such as the high-precision oscillators. We are in close contact with those manufacturers and our best guess right now is we will have all components by mid-November.
Once we have the components, our manufacturing partner in Taiwan can very quickly produce the entire lot of LimeSDRs. The assembled boards will then be sent to the UK for final quality assurance and packaging before heading off to Crowd Supply’s warehouse for delivery to all backers.
Given all this, we expect all LimeSDRs, including the Aluminum Kit version, to be delivered in December. Of course, we will update everyone as soon as have more information. In any case, we will post an update at least once a week between now and delivery.
Update Your Shipping Address
You will know your order has shipped when you receive a shipping confirmation email from Crowd Supply. The shipping confirmation email will contain a tracking number. If you need to change your shipping address, you can do so by logging into your Crowd Supply account. If you didn’t already have a Crowd Supply account, one was automatically created for you when you placed your order. We will post a separate update letting you know about the cutoff date for updating your shipping address.
Hardware and BoM
We have been contacting all the component suppliers and manufacturers and placing orders through our operation in Taiwan. As part of this work we wanted to make sure that no component will become end-of-life for at least 2 years. As a result, we have had to make minor changes to the board to replace some of the older parts. This was followed by another set of prototype runs to ensure that there is no impact on performance and manufacturability of the boards.
First batch of the Altera FPGA parts delivered to Lime headquarters yesterday.
Production Testing
A rigorous testing programme is essential with an advanced technology platform such as the LimeSDR and this work has just been completed. The LMS7002 production test had already been verified and running on industry standard Teradyne testers with RF test configuration. The program for the LimeSDR boards runs on x86-based workstations and provides an optimised test time while exercising all the functions, including frequency and bandwidth sweep across the full range.
Driver and Software Updates
We have already shipped over 100 boards to our community of beta testers for their feedback, before, during, and after the campaign. This enabled us to provide so many truly exciting updates during the campaign and, more significantly, we have been getting excellent feedback from the community, who have been simply outstanding in sharing their ideas for improving the user experience. We are making significant updates to the driver and calibration algorithms as a result, these are largely complete and will be pushed to Github before the end of November.
Documentation
We will continue to invest heavily in this area and see this as being key to demonstrating our steadfast commitment to the community. Giving you the best support begins with well structured documentation. Obviously, we rely here on your input and feedback. Making the process as smooth as possible is key, we have already started to publish data sheets and supporting documentation on the Myriad-RF Wiki, and will continue to do so as we gather your comments and suggestions.
LimeNET App Store
One of the key activities which we believe will set LimeSDR apart from other software-defined radio solutions is the concept of app-enabled SDR. With this, developers can provide their solution as a incredibly simple to install app, complete with all the various dependencies — with optional support and certification etc. — and publish it via the LimeNET app store. We envisage a rich ecosystem of many applications, resulting in a fantastic out-of-the-box user experience as the maturity and sophistication of the algorithms and software routines improves over time.
We are working very closely with Canonical (the organisation behind the immensely popular Ubuntu Linux distribution) to put in place the app store infrastructure and plan to have a basic service running and populated with a few initial apps by the time the first boards go out.
We are currently in the process of setting out the criteria for publishing an app in the LimeNET store, along with the associated terms and conditions. This is another area where we plan to seek input from you, our backers, to encourage the widest participation and cater for a variety of business and revenue models for developers. There will be numerous posts and updates on this topic, with plenty of opportunity for your input, comments, and feedback.
Last but not least, we shall be posting regular updates as we get closer to the deadline. This will be similar to during the campaign and with plenty of details, including things such as component delivery status, manufacturing progress, and delivery dates for the pledges made by you in all the different categories.
Thank you once again for your support and here’s to the exciting weeks ahead!
Coherent-receiver.com is a company which is a customer of our RTL-SDR V3 dongle and they have been working on creating a multi-channel coherent receiver product based on the RTL-SDR. An RTL-SDR multi-channel coherent receiver is at its most basic, two or more RTL-SDR dongles (multi-channel) that are running from a single clock source (coherent). A multi-channel coherent receiver allows signal samples from two different antennas to be synchronized against time, allowing for all sorts of interesting applications such as passive radar and direction finding.
The team at coherent-receiver.com have used the new expansion headers on our V3 dongles to create their product. In their receivers they attach a control board which has a buffered 0.1 PPM TCXO (buffered so it can power multiple RTL-SDR’s). They also added an 8-bit register and I2C connection capabilities which allows for control of future add-on boards. The I2C capability is useful because it means that several RTL-SDR dongles can be controlled and tuned from the same control signal. More information on the registers and build of the receiver control board can be seen on their technical support page.
A ten channel RTL-SDR coherent receiver.The Coherent Receiver block diagram.
One example application of a multi-channel coherent receiver is passive radar. Coincidentally, we’ve just seen the release of new GUI based Passive Radar software by Dr. Daniel Michał Kamiński in yesterdays post. Passive radar works by listening for strong signals bouncing off airborne objects such as planes and meteors, and performing calculations on the signals being received by two antennas connected to the multi-channel coherent receiver.
A second example is direction finding experiments. By setting up several antennas connected to a multichannel coherent receiver calculations can be made to determine the direction a signal is coming from. An interesting example of direction finding with three coherent RTL-SDRs can be seen in this previous post. A third example application is pulsar detection which we have seen in this previous post.
Coherent-receiver.com sent us a prototype unit that they made with four of our V3 dongles. In testing we found that the unit is solidly built and works perfectly. We tested it together with Dr. Kamiński’s passive radar software and it ran well, however we do not have the correct directional antennas required to actually use it as a passive radar yet. In the future we hope to obtain these antennas and test the coherent receiver and the software further.
Currently they do not have pricing for these models as it seems that they are first trying to gauge interest in the product. If you are interested in purchasing or learning more they suggest sending an email to [email protected]. It seems that they are also working on additional RTL-SDR ecosystem products such as filters, downconverters, antennas and LNAs.
We hope that the release of this product and Dr. Kamiński’s software will give a boost to the development of coherent multi-channel receivers as we have not seen much development in this area until recently.
Back in April 2016 the KiwiSDR was successfully funded on Kickstarter. Since then almost all the rewards have been mailed out and the number of worldwide receivers available on sdr.hu has increased. KiwiSDR is an SDR cape (add on) for the BeagleBone Black/Green embedded computer which covers 0 – 30 MHz with 30 MHz bandwidth. It’s main purpose is to be used as a web based remote receiver which can be publicly accessed by many users.
Over on the Kickstarter updates page we see news that Seeed Studio is taking over the production and distribution of the KiwiSDR, and soon you’ll be able to order the KiwiSDR cape directly from their online Bazaar. Seeed studio is the same company that produces several other capes for the BeagleBone and they also produce the BeagleBone Green which is needed to run the KiwiSDR. They write:
We are very pleased to announce an agreement for Seeed Studio to take over production and distribution of the KiwiSDR going forward. What does this mean? Until now Seeed only had a contract with us to produce the Kickstarter rewards and pre-orders. Now Seeed will add the KiwiSDR to their family of BeagleBone capes they manufacture and distribute. Very soon you’ll be able to order the KiwiSDR directly from Seeed’s online Bazaar, pay directly with a credit card or Paypal and use their shipping system.
For us, and you as Kiwi owners, this is a very positive development. It means soon we’ll be able to devote the majority of our time to software development and providing you support. And as you probably know there is a large list of bugs, feature requests, extensions, distributed experiments and educational material we’d like to be working on instead of worrying about shipping and manufacturing issues. Improving the software is the best way to differentiate ourselves in a crowded SDR marketplace.
We would appreciate it if you would continue to purchase from us until our stock is depleted. Seeed has already manufactured a significant number of units alongside our prior build and will be able to meet the demand immediately. We thank everyone at Seeed for their fantastic effort in making KiwiSDR a reality.
Outernet is a new L-band satellite services which aims to be a “library in the sky”. Their satellite signal can be received from almost anywhere in the world, and they aim to constantly transmit data like news, weather updates, books, images/videos and other data files. The service is free and can be received with an RTL-SDR, LNA and patch antenna. We have a full tutorial on receiving their service available here.
The “rxOS” decoder, file management system and web interface GUI has recently been updated to version 3.0. This new version has several new features:
Downloaded files are automatically decompressed after downloading, so they can be viewed directly in the Outernet web interface.
An hourly transmission of APRS data which comes from the repeater on board the international space station. APRS messages can now be relayed across the world via the ISS and Outernet.
This Monday they will begin transmitting NOAA weather data (we are unsure if this entails images or text data yet)
Soon they should begin transmitting news data too.
More details on the update can be found on their forum post. To update the service on a CHIP or Pi 3, download the .pkg file from the links on the forum and choose this file in the Update Firmware section of the Outernet settings menu.
An example of some received APRS messages from the Outernet.APRS messages
Version 2.6 of the popular SDR program GQRX has just been released (changelog). GQRX is a general signal browsing program similar to programs like SDR#, HDSDR and SDR-Console. However GQRX is designed to run on Linux, MacOS and Raspberry Pi 2 & 3. Note that v2.6 is still a work in progress for MacOS. Apart from the new features and bug fixes, one of the major improvements appears to be reduced CPU usage, meaning that it should run better on older PCs. The changelog is pasted below:
New features
1-2-5 scaling on FFT axis.
Audio waterfall.
Remember AGC settings between sessions.
Right-click on FFT resets frequency zoom.
Separate dB ranges for pandapter and waterfall.
Raw I/Q mode.
Portaudio support.
Command line option to set Qt style (fusion, windows, …)
Binary packages for Raspberry Pi 2 and 3 (see below)
Bugs fixed
Stuttering audio with Pulseaudio backend.
Use system font on FFT plot (too small font on high res displays).
Broken FUNcube Dongle Pro+ support on Mac OS X 10.11.4.
Correct display of negative offsets between -1 and 0 kHz.
Reset frequency digits below the one that is being changed.
LNB LO could not be set from I/O configuration dialog.
Update squelch level when switching between demodulators.
Set correct filter range when loading bookmark.
White area on waterfall.
RFSpace Cloud-IQ support on Mac OS X, RPI binaries and in PPA.
Miscellaneous improvements
Input decimator performance.
SDRPlay integration through SoapySDR.
Only probe for devices when the program is started.
