Tag Archives: Software Defined Radio

An inexpensive Windows tablet for portable SDRs?

A tablet with two USB ports would be ideal.

I’ve never been a fan of tablet PCs. I have an old Android tablet that I occasionally use to watch Netflix and read eBooks, but when I want to interact with a computer, I typically want the convenience of a proper keyboard and the precision of a mouse or large track pad.

With that said, this year at the Winter SWL Fest, I was co-host of a forum called: “Time Travel, Teleportation & Spectrum Hoarding for the Contemporary DXer.” My good friend and co-host, Mark Fahey brought his Windows tablet PC and we used it to demonstrate how easily and effectively SDRs can be taken to the field and spectrum recordings can be reviewed practically anywhere. Indeed, Mark tunes through his spectrum recordings while taking the train to work! (How cool is that!?!)

This week, I reviewed a guest post about portable SDRs by London Shortwave; afterward, I decided that I must begin the search for a Windows tablet. Since I would only use this tablet for portable SDR work, I really want to keep it as affordable as possible ($200 US or less).

It appears to me that there are a few things that you must overcome in a portable SDR package including: mitigating internal noise produced by the tablet and accessories, and the ability to power the tablet and the SDR at the same time.

Windows Tablet Wishlist:

  • Inexpensive (less than $200)
  • Enough speed and memory to run SDR applications and record spectrum to an internal SD card or external portable drive
  • Separate USB and power ports or the ability to power both the tablet and SDR at the same time

My choices so far:

Readers: Your recommendations and advice are most welcome! Please comment especially if you have experience using tablet/SDR combos.

Roundup of software defined radios

 

RTL-SDR

Many thanks to several readers (including Mike and Greg) who have shared a link to RTL-SDR.com’s Roundup of Software Defined Receivers. The list gives an excellent, comprehensive overview of SDRs currently on the market. I encourage you to check it out.

Indeed, while you’re at RTL-SDR.com, take a look at their active blog and forum to get the most out of your RTL-SDR dongle!

SDRplay RSP: now $149 or £99

SDR-PLay-RSP

I just received the following tweet from @SDRplay:

We’ve been able to reduce the SDRplay RSP price to $149 or £99 (approx €149 ) + tax/shipping. See

I’ve just started reviewing the SDRplay RSP for the June 2015 issue of The Spectrum Monitor Magazine. Preliminary impressions of this SDR are quite positive–especially for a receiver in this price class. At $149 US, the SDRplay RSP is now less expensive that the Funcube Dongle Pro+. Indeed, the RSP is even less expensive than portables like the Tecsun PL-880 and Sangean ATS-909X.

Over the next two months (as I get to know the RSP better) I will post the occasional broadcast recording using the SDRplay RSP with HDSDR and SDR#.

The Quadrus SDR: A New Military-Grade Software Defined Radio Receiver

Quadrus-SDRDr. Bertalan Eged of Spectrafold Technologies recently contacted me regarding a new military grade SDR they’ve produced: the Quadrus SDR. Today is the Quadrus official release.

The Quadrus SDR has phase-coherent multi-channel capabilities with up to 16 channels, which means that it can be used for direction finding, diversity reception, as well as MIMO applications.

While the Quadrus line is aimed squarely at government and scientific research markets, the $1490 US Quadrus DRU-244A-1-1-PCI, a four-channel SDR, might appeal to the discerning DXer, amateur radio operator, or radio experimenter.

Below, I’ve posted the full press release from Spectrafold Technologies along with several photos and screen shots.

Since I’m not a radio engineer, I’ve asked a representative of Spectrafold to answer any questions you may have about the Quadrus SDR line and its receiver architecture.


Military-Grade Software Defined Radio Receiver Platform
Now Commercially Available for Building Better Receivers

Quadrus-SDR-2

Phase-coherent, Multi-channel Quadrus Platform Brings New Features to Commercial Market

Spectrafold Technologies today released the Quadrus software defined radio (SDR) platform for commercial use, enabling access to advance, professional-grade platform for signal intelligence, spectrum monitoring communications systems and missions. The long-standing platform has features are still unmatched by other commercially available products, and include four cutting-edge, phase-coherent antenna inputs with 16 bit, 80 MSPS; high-sensitivity, high-dynamic range Analog-to-Digital Converters (ADCs) driven by a low phase noise; and high-stability sampling clock. The input signal chain also contains a Low-Noise pre-Amplifier (LNA) and an input leveling attenuator providing the necessary sensitivity while still maintaining the proper input drive. The architecture provides the capability of using high gain antennas, and standing against the overload by the crowded radio spectrum.

“Today there is strong international community of radio enthusiasts and listeners using SDR technology, looking for platforms that implement advanced radio signal processing algorithms,” said Dr. Bertalan Eged, chief architect of the Quadrus. “Physically and logically phase-coherent multi-channel SDR platforms provide the capability to implement various algorithms and receivers such as diversity reception, interference cancelling, beam forming and correlative receivers. These applications can help to deliver better sensitivity, more stable fading free reception, longer connectivity and collecting more information on the radio signal environment.”

The platform input bandwidth is wide enough to be used up VHF/UHF bands as Direct Digital Receiver (DDR). The samples are fed into an FPGA, where a non-blocking switch matrix is used to forward them to the input of the four on-board receiver signal processors. The on-board processing is capable of forming a 16 multi-channel receiver. The platform also features a standard PCI interface for PC integration, and comes with a Windows®32 bit kernel driver and fully open API, which can be downloaded from the website along with the operating SDR software. The SDR receiver software has remote control capability for system level integration via TCP/UDP/IP links. Further details on these capabilities are available at the Spectrafold website. The system has spectrum recording capability to binary files, some example can be downloaded for evaluation purposes.

SAGAX DRU244A-1-1-PCI  Stock photo 15-Jan-2015

The Quadrus API is available as a Windows® DLL, and developers and system integrators may download it from the SUPPORT page on the Spectrafold website. The hardware API is meant for direct hardware access, but a higher level remote control interface API is available as well, which can be used to (i) set up the receiver channel parameters and to (ii) access the IF as a UDP/IP stream. If you prefer to not use any of these methods, it is possible to fall back to a virtual audio card connection between the SDR software and external applications, like decoders and post processors.

Additional information on the performance and usage scenarios is available in the BLOG. Users interested in experimenting with the hardware can gain access to remote access to a computer with SDR hardware digitizer and installed SDR software. Interested parties should contact the team by email: [email protected]

Hardware orders may be placed through the manufacturer’s ORDER page. Standard secure payment option is provided via PayPal. International shipment by UPS is part of the service. The hardware is manufactured in batches with limited stock. Introductory pricing starts at $1490.

###

About Spectrafold Technologies

Spectrafold is a dedicated community of professionals, who work tirelessly to invent and create affordable, cutting edge SDR solutions. Together we have decades of hands-on experience delivering working solutions to the toughest missions and environments. Our customers include academic, governmental, and military organizations, but radio enthusiasts as well.


Screen shots

Click to enlarge:

srm-4 srm-3 srm-2 srm-1

23 January 2015: A Friday morning 31 meter band scan

31-Meter-Waterfall-SpectrumThis morning, I tuned around the 31 meter band and was surprised with favorable propagation out of Asia (see spectrum waterfall above–click to enlarge).

I started logging a few stations, but the effort quickly turned into a full band scan/survey.  I logged everything I could easily hear between the 9,390-10,000 kHz portion of the 31 meter band.

I logged 52 stations and omitted eight that I considered too weak for good copy.

I used my WinRadio Excalibur SDR connected to a large horizontal delta loop wire antenna.

The number of broadcasts originating in or targeting China is pretty phenomenal: the 31 band is your oyster, if you speak Chinese.

31 Meter Band 1200 – 1300 UTC, all frequencies in kHz

  • 9390 Radio Thailand Malaysian (1200Z) then English (1230Z)
  • 9410 China National Radio 5 Chinese
  • 9430 FEBC Radio Chinese
  • 9440 China Radio International Cambodian
  • 9460 China Radio International English
  • 9475 Radio Australia English
  • 9490 Voice Of America Korean
  • 9500 China National Radio 1 Chinese
  • 9515 China National Radio 2 Chinese
  • 9530 Voice Of America Chinese
  • 9540 China Radio International Chinese
  • 9550 China Radio International Vietnamese (covered by CRI Cantonese distortion)

    Note the CRI signal on 9,570 kHz which is blanketing the surrounding spectrum with noise.

    Note the blowtorch CRI signal on 9,570 kHz which was blanketing the surrounding spectrum with noise.

  • 9570 China Radio International Cantonese (transmitter spewing distortion 50 kHz wide)
  • 9580 Radio Australia English (covered by CRI Cantonese distortion)
  • 9590 China Radio International Russian (covered by CRI Cantonese distortion)
  • 9600 China Radio International English
  • 9620 China National Radio 6 Chinese
  • 9635 Voice of Vietnam 1 Vietnamese (slightly below freq)
  • 9640 Radio Havana Cuba Spanish
  • 9645 China Radio International English
  • 9655 China Radio International Chinese
  • 9660 Radio Taiwan International Chinese
  • 9680 Radio Taiwan International Chinese
  • 9700 Lower Sideband communication (UNID)
  • 9710 China National Radio 1 Chinese
  • 9720 China Radio International Filipino
  • 9730 China Radio International English
  • 9735 Radio Taiwan International Indonesian
  • 9740 BBC English
  • 9745 Guanghua zhi Sheng Chinese
  • 9750 Radio Kuwait Arabic
  • 9730 China Radio International English
  • 9770 KBS World Radio Chinese
  • 9775 China National Radio 2 Chinese (vy weak)
  • 9785 China Radio International Laotian
  • 9790 Voice Of Islamic Republic of Iran Pashto
  • 9810 China National Radio 2 Chinese and All India Radio Telugu
  • 9820 Radio Havana Cuba Spanish
  • 9825 Voice Of America Chinese
  • 9830 China National Radio 1 Chinese
  • 9840 Voice of Vietnam English
  • 9850 Radio Habana Cuba Spanish
  • 9855 China Radio International Chinese
  • 9860 China National Radio 1 Chinese (vy weak)
  • 9880 KSDA-AWR Guam Korean (vy weak)
  • 9900 Radio France International Chinese
  • 9920 FEBC Radio Bahnar (w/Jamming)
  • 9940 Reach Beyond Australia (HCJB) Indonesian
  • 9955 Radio Slovakia International English (via WRMI/WRN)
  • 9975 KTWR Guam Chinese
  • 9990 Radio Farda Persian
  • 10000 WWV Fort Collins English

I recorded two broadcasts during the scan–both at 12:30 UTC: Radio Thailand (9,390 kHz) and Radio Slovakia (9,955 kHz). I will post them soon.

Excellent website dedicated to the RTL-SDR

RTL-SDRSWLing Post reader, Mike, writes:

Check this website – not only does it cover RTL dongles, but others as well as Airspy…

http://www.rtl-sdr.com/

Many thanks, Mike. The depth of RTL-SDR.com is most impressive. They seem to post near daily updates on their blog.

Perhaps it’s time I jump into the RTL-SDR craze and get an upconverter as well to work HF. I’ve hesitated making this modest investment in the past because I have other top-shelf SDRs. A dongle, however, would certainly prove to be ultra-portable; especially for one bag travel.

Video: Controlling the Elad FDM-S2 SDR with the HP Stream 7 tablet

Elad-FDM-S2-FrontPanelMany thanks to SWLing Post contributor, Guy Atkins, who shares the following video demonstrating how the Elad FDM-S2 can be controlled with the $99 HP Stream 7 Windows 8.1 tablet PC:

You can read more about Guy’s FDM-S2/HP Stream 7 setup in his previous post.