Category: News

New Experimental R820T RTL-SDR Driver that Tunes down to 13 MHz or Lower

Over on the Osmocom mailing list, Oliver Jowett an RTL-SDR experimenter has posted about his new experimental driver for the R820T RTL-SDR which extends the tunable range down to around 13 and up to 1864 MHz (previously 24 – 1766 MHz). Oliver writes

You can get these changes from’ll need to build from source yourself). There should be no application changes needed, just tune as normal. (gqrx needs the “no limits” option turned on)

These changes work by limiting the tuner to a range of frequencies that it can reliably tune to, then allowing tuning beyond those bounds by making the 2832’s downconverter do the final bit of tuning. This can add up to 14.4MHz to each end of the range. Also, the tuner is switched to low-side mixing at the top of the range which gives a bit more range there. The practical range is limited by the width of the IF filter and aliasing effects at the extreme edges of the downconverter’s range.

I’ve been able to pick up broadcast AM and amateur CW/SSB down to around 15.5MHz without too much trouble.

I’d be interested to know how this works for others. Also.. these changes are likely to have broken offset tuning, direct sampling mods, and tuners other than the R820T, as it touches all those areas but I only have an unmodified R820T to test against. If you have different hardware and are willing to spend some time testing then please let me know. I expect that the range of the other tuners can be extended in the same way with not much trouble.

Over on the Reddit RTL-SDR discussion board there has been talk about this patch. Most users are reporting that it works well down to around 15 MHz, but some people are reporting that they have been able to receive signals down to around 4 MHz. Testers also report that this modified driver works much better than the no-hardware direct sampling mod patch released a few months ago.

Update: Commenter J.B has been kind enough to upload a ready to go Windows binary for SDR#. Download here Simply copy the files in the zip into the SDR# folder.

Reddit user gat3way was able to take this screenshot showing AM reception at 9.5 MHz
Reddit user gat3way took this screenshot showing AM reception at 9.5 MHz

Micheal Ossmann’s Software Defined Radio Course

Micheal Ossmann, creator of the HackRF is starting an online video course on the topic of software defined radio (SDR). His course will cover GNU Radio and will help you to learn the fundamentals of digital signal processing. The first video has been released and in this video Micheal shows how to set up a broadcast FM receiver in GNU Radio.

To do the exercises in the course you will need a HackRF or other similar SDR radio. Most exercises involving reception only should be compatible with the RTL-SDR with some small modifications relating to things like the changing sample rate.

FlightAware Introduces PiAware for use with RTL-SDR and dump1090 on a Raspberry Pi

FlightAware is an online service providing real time flight tracking. The flights are primarily tracked by volunteers who run ADS-B decoding hardware which is networked through the internet to the FlightAware servers.

Now FlightAware have written in to to let us know about their new PiAware software which enables a Raspberry Pi running dump1090 to contribute data to the FlightAware network. Dump1090 is a popular RTL-SDR compatible ADS-B decoder program for Linux systems.

A major perk for running their software and contributing data is that FlightAware will buy you a licensed copy of PlanePlotter.

The press release provided is quoted below.

If you are running an inexpensive Raspberry Pi ADS-B receiver with dump1090 then you can install the PiAware Package from FlightAware to freely view nearby flight traffic and transmit this data to FlightAware’s tracking network.  Most aircraft within Europe by 2017 and USA by 2020 will be required to have ADS-B transmitters onboard.
FlightAware’s user-hosted worldwide ADS-B receiver network tracks about 90,000 unique aircraft per day and feeds this live data into the FlightAware website in combination with other public/private flight tracking data sources.  FlightAware has over 500 user-hosted ADS-B sites online across 60 countries, with top contributors tracking over 10,000 aircraft per day.  To see how ADS-B data is put to use, check out the FlightAware Live Map.
The PiAware installation process takes only a few minutes.  If you don’t have PlanePlotter, you can download it and then send FlightAware your installation’s serial number and we’ll buy you a license.  FlightAware will also give users a free Enterprise Account ($90/month value) in return for installing PiAware.
FlightAware Real Time Map Example

XiOne – A RTL2832U based Portable Software Defined Radio: Indigogo Funding Campaign

A new funding campaign for an RTL2832U based software defined radio has gone up on Indiegogo. The new SDR is called the XiOne and is intended to be the first SDR that is easy to use with smartphones and open to the maker community.

With its 100 kHz to 1.7 GHz receiving range, the XiOne has a similar tuning range to the standard RTL-SDR dongles when an upconverter or the direct sampling mod is used. What makes the XiOne different is that it will have a built in MIPS processor, an internal rechargeable battery for portability and it will connect directly through WiFi to a smart device. They are also developing SDR GUI software for mobile devices including decoders for things like ADS-B, AIS and NOAA Satellites.

The IndieGoGo backer price for a XiOne is $179 USD, but if you act fast there are 100 units available at the promotional price of $139 USD. At the moment they have a working prototype with completed firmware, portable Java based SDR GUI, iPhone demodulation software, a MacOS ADS-B receiver, an iPad AIS receiver and an iPad spectrum analyzer. The fundraiser is to help them begin serial production.

There is a Reddit thread discussing the project here.

XiOne Prototype Internals
XiOne Prototype Internals
XiOne Casing
XiOne Casing

Fundraising for RTL-SDR Development

Kyle Keen, the primary author of the well known and highly used rtl_fm, rtl_power, rtl_adsb and recently released rtl_sdl tools has started an indiegogo fundraiser to help raise funds to pay salary for ideally at least one month of dedicated RTL-SDR software coding. Kyle is hoping for $3,000 USD per month of coding. The time he codes for will scale proportionally to the amount of funds raised.

There are several levels to contribute at but the ideal contribution is the ‘Voter’ level at $50 USD. By contributing to the fundraiser at the ‘Voter’ level you will be able to have a vote on what features are to prioritized. It is also possible to contribute at a lower level of $10 USD and forego the voting perk.

The list of features to be implemented and the voting system can be found at Important improvements will be made to the librtlsdr library, rtl_sdl, rtl_adsb, rtl_tcp, rtl_power and rtl_fm..

We hope that if you have enjoyed the RTL-SDR in some form you will contribute to this developer and help make this hobby an overall better experience.

New Ebook: The Hobbyists Guide to RTL-SDR

We at have just released an Ebook for Kindle titled “The Hobbyists Guide to RTL-SDR: Really Cheap Software Defined Radio”. For the first few days we are selling it at a reduced price of $4.99USD (half price). If you are an Amazon Prime member you should also be able to lend it from the Kindle library for free. If you’re unsatisfied with the book remember that you can always refund it within 7 days of purchase.

The book covers many of the tips and tutorials found in this blog in a more in depth manner as well as containing many more new tutorials and RTL-SDR related information. Check out the table of contents in the sample for an idea of what the book contains. The content is mainly intended for people new to the RTL-SDR.

Remember that you don’t need a Kindle device to read Kindle books! There are readers available for Windows, Mac, Web Browsers, Android and iOS as well.

If you enjoy our book please remember to leave a review on the Amazon page.

The Hobbyists Guide to RTL-SDR: Really Cheap Software Defined Radio
The Hobbyists Guide to RTL-SDR: Really Cheap Software Defined Radio

SeeDeR: New SDR GUI Software Supporting RTL-SDR

SeeDeR is a new software defined radio GUI program that supports the RTL-SDR. It also supports the Funcube Dongle and BladeRF. Currently it is in an early beta release.

SeeDeR contains features specifically developed for decoding radio data transmissions from satellites – in particular the crowdfunded SkyCube satellite – such as a built-in AX.25 decoder, and a satellite pass predictor.

SeeDeR requires a PC with Windows 7+, 1+ GB RAM, 2+ GHz dual-core CPU, 20 MB HD space. The executable is 32-bit.

We need to note that SeeDeR has been a cause of some friction with the author (Youssef) of SDR# and may be part of the reason why SDR# was temporarily removed. Youssef is claiming that SeeDer has illegally used licenced code from SDR#, however the author of SeeDer refutes that claim.

SeeDeR Software Defined Radio GUI
SeeDeR Software Defined Radio GUI

SDR# Website and Downloads Removed

Update: The author has updated the website with an explanation of why he took it down. He has also restored download functionality so now sdr-install.bat will work again.

The SDR# website, download links and repositories have been taken down and probably won’t be back for a number of days or weeks. This means the sdr-install.bat file will not work as well. If you already have SDR# installed it will continue to work as normal.

We aren’t exactly sure why this has happened, but it seems the author of SDR# did not like the many forks of the software that have been recently popping up. The forks may have been violating the licence that SDR# is under.

If you are new to RTL-SDR, our Quickstart guide has guides to using HDSDR and SDR-CONSOLE to try while SDR# is unavailable. HDSDR and SDR-CONSOLE are two good alternatives to SDR# but are slightly more difficult to set up and use.

See the Reddit discussion on this here.

HackRF Now Available for Preorder

The HackRF One, a TX/RX capable software defined radio for 10 MHz – 6 GHz is now available for preorder at certain resellers for $299USD . Micheal, the man behind the HackRF expects the Kickstarter HackRF rewards to be shipped in June. Then after shipping the HackRF reward units, the resellers will receive their units.

HackRF One from Great Scott Gadgets is a Software Defined Radio peripheral capable of transmission or reception of radio signals from 10 MHz to 6 GHz. Designed to enable test and development of modern and next generation radio technologies, HackRF One is an open source hardware platform that can be used as a USB peripheral or programmed for stand-alone operation.

  • 10 MHz to 6 GHz operating frequency
  • half-duplex transceiver
  • up to 20 million samples per second
  • 8-bit quadrature samples (8-bit I and 8-bit Q)
  • compatible with GNU Radio, SDR#, and more
  • software-configurable RX and TX gain and baseband filter
  • software-controlled antenna port power (50 mA at 3.3 V)
  • SMA female antenna connector
  • SMA female clock input and output for synchronization
  • convenient buttons for programming
  • internal pin headers for expansion
  • Hi-Speed USB 2.0
  • USB-powered
  • open source hardware

HackRF One has an injection molded plastic enclosure and ships with a micro USB cable. An antenna is not included. ANT500 is recommended as a starter antenna for HackRF One.


HackRF One
HackRF One

Interest Check for an ADS-B Folded Monopole Antenna

Adam, manufacturer of the LNA4ALL and LNA4HF is putting out an interest check for an ADS-B folded monopole antenna. The antenna can efficiently cover the 1030 MHz to 1090 MHz frequencies that are used by ADS-B.

The major advantage to Adams antenna is that it uses a DC grounded design, eliminating static build up problems that can potentially fry your LNA or RTL-SDR dongle.

If there is sufficient interest, Adam will sell the antenna for 20 Euros.

ADS-B Folded Monopole Antenna
ADS-B Folded Monopole Antenna