Category Archives: Digital Modes

Software Defined Receivers (SDRs) for the visually impaired listener

At the 2015 Winter SWL Fest, I co-hosting a forum on Software-Defined Radios. Afterwards, a radio friend–who happens to be visually impaired–approached me to ask:

“What is the best SDR for those who are blind or visually impaired?”

I’d never been asked the question before, and replied that I’d have to do a little research. In truth, I suspected that research would turn up very little that was useful: after all, SDRs require a lot of pointing and clicking, and some of the interfaces are rather complicated. Spectrum and waterfalls displays, often at the heart of the SDR app, are visual displays.

But I kept thinking of my friend’s question. Upon my return, I set out to do a little research and possibly pose the question here on the SWLing Post. Then assistance stepped in…in the form of medium wave DXer Tore Johnny Bråtveit.

If Mr. Bråtveit’s name sounds familiar, that would be because I recently posted a link to an Oregon Public Broadcasting interview with him. In the interview, he mentioned that he uses SDRs to chase MW DX, and that he is visually impaired.

I reached out to Mr. Bråtveit via his website and asked for any advice he could give about SDRs for those who are blind or visually impaired. His enlightening response:

“In the interview I mentioned screen reader software and the need to find SDR software that plays well along with such screen reader software. For those visually impaired who have some eyesight, this aspect may not apply, since many of them are well helped by a screen magnifier software package.

For those without eyesight at all, or with so little left of the eyesight that they cannot make practical use of the screen, there are these screen reader software packages. They all do the same, but they solve the job in a somewhat different way and are good at different tasks.

I began using SDRs back in 2007. First I used some [RFspace] SDR-IQs for a few years, until I purchased a Winradio G31DDC in 2010. The user experience with Winradio was so good that I have stayed with those radios since then, using both G31DDC and G33DDC receivers at my remote listening places.

I think I can say that all the software packages delivered with SDRs have issues and challenges when it comes to using them along with a screen reader. The worst example of unusable native software I have seen so far, is the software package delivered with the [Microtelecom] Perseus. I had a thought purchasing one some years ago and make some scripts for my screen reader JAWS to see if I could make the Perseus possible to use effectively, but I dropped the idea at that time in favor of Winradio.

The SpectraVue software delivered with SDR-IQ was usable, but I had to script it quite extensively, especially to be able to use the timeline when playing back recordings. Also the frequency selector was a bit tricky, so I had to assign some hotkey combinations to it. Otherwise it worked fine.

The Winradio software for the G3x series works quite fine right out of the box. They have apparently thought [through] keyboard operation, and there are shortcuts for almost everything. Such shortcut keys are necessary, as navigating the program interface with a screen reader can be a bit too complicated, especially for those only using speech output from the screen reader to access the screen content.

I personally am living in a country where we have good access to refreshable Braille displays, which gives me the opportunity to turn off the speech entirely if I want and only use Braille output. This way I can navigate the program interface quite effectively to understand how things are laid out.

The only real issues I have had with Winradio software, is:

1. Changing shortcut keys:
Normally, the Tab key is used to move between elements on a screen, so it would be natural to think that pressing the Tab key will bring me to the next shortcut key definition. Not in Winradio. Tab can be defined as a shortcut key itself, so trying to navigate the shortcut keys dialog with that key gives you a number of options, all connected to the Tab key. My way around this was to navigate with the Braille display until I found the shortcut key definition I wanted to change, focus on it by pressing a cursor routing key in that position and changing the definition. Then navigate further down to the OK button and activate it.

2. The timeline:
The timeline used when playing back recordings can be hard to locate when using a screen reader, and even more difficult to work with, since when you press a cursor routing key on the Braille display to simulate a mouse click on it, the focus often moves to somewhere else on the screen. Then you have to work hard to locate back to that timeline again. My solution here was to script my screen reader with a hotspot at the timeline with a shortcut key assigned to it, so that I could move focus back there by pressing a key.

Among the third-party software packages developed for SDRs, I have found few that I can recommend. The only one I can think of, is HDSDR. Especially in the current version from November 2013, there are a number of useful shortcut keys, and the program seem to work very well. I have used it a bit with an AFEDRI SDR I have, and have also used it to play back older SDR-IQ recordings.

So, if nothing else works, Iwould say that HDSDR is the solution, since it is both easy to use and have support for a number of receivers. And it is free, as you certainly know.

[…]Please write back if I can help you any further”

Brilliant! What a treasure trove of information for our visually-impaired SDR listeners and operators. Thanks so much, Mr. Bråtveit, and please keep in touch with us here at the SWLing Post. 73s!

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VOA Radiogram #100

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Dr. Kim Elliott, has been transmitting VOA Radiograms to a devoted set of global listeners for two years. Indeed, he recently passed a milestone by transmitting the 100th episode of the VOA Radiogram. Most impressive!

SWLing Post reader, Harald (DL1ABJ), recently sent the following message regarding reception of the 100th episode:

Dear Thomas,

Last weekend I decoded VOA Radiogram #100 on 17860 kHz AM (via Greenville, Edward R. Murrow TX station) from 1600 till 1630 UTC here in Germany.

Part of it was a text by Kim Andrew Elliott, KD9XB, telling a bit about his project of broadcasting text and pictures over AM transmitters on shortwave.

I am also attaching one of the pictures sent during VOA Radiogram #100.

Regards

Harald

VOARadiogram100

Click here to view/download Harald’s text file (.RTF).

Many thanks for sharing this, Harald. VOA Radiograms are successfully decoded by listeners across the world. If you’re interested in decoding a VOA Radiogram, or simply following the broadcasts, bookmark VOAradiogram.net.

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Kyodo News Agency Fax and the Sony CRF-V21

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My friend, @K7al_L3afta, posted to Twitter, the following fax he decoded from the Kyodo News Agency on 12,745 kHz today:

The Kyodo News Agency is possibly the last marine weather fax station which faxes daily news (full newspapers) and navigational warnings to ships at sea.

For those of you who might believe it takes a sophisticated setup to decode a FAX transmission, you would be incorrect. @K7al_L3afta uses only a Tecsun PL-660 portable hooked up to his PC running the MultiPSK application. He lives in Morocco–in an urban environment with lots of RFI as well, so those of you living in a similar situation should feel encouaged.

After posting the FAX image, our friend @LondonShortwave then sent a link to a Sony radio I have never seen before: the Sony CRF-V21.

The Sony CRF-V21 (Image source: Universal Radio)

The CRF-V21 is a full-featured shortwave radio receiver with built-in printer and decoding for FAX and RTTY. In fact, with an optional AN-P1200 satellite antenna, the CRF-V21 will even copy and print G.O.E.S. satellite weather transmissions.

Here is Universal Radio’s archived description of the CRF-V21:

The Sony CRF-V21 Visual World Band Radio is the first portable to offer integrated facsimile (FAX) and radioteletype (RTTY) shortwave reception. You can print RTTY and FAX transmissions directly with the built-in thermal printer. Supported RTTY modes include Baudot at 60, 66, 75 and 100 WPM and ASCII at 110, 200, 300 and 600 bps. FAX shortwave speeds include 60, 90 120 and 240 rpm. Even G.O.E.S. satellite weather transmissions may be copied and displayed with the optional AN-P1200 satellite antenna.

Frequency coverage is 9 kHz to 30 MHz for all longwave, medium wave and shortwave frequencies. Plus FM coverage from 76 to 88 MHz and NOAA satellite channels 137.62/141.21 MHz. The optional AN-P1200 antenna system adds 1.6910/1.6945 GHz G.O.E.S. satellite reception. Another highlight of this radio is built-in spectrum display showing a visual picture of 200 kHz or 5 MHz of the shortwave spectrum.

Other refinements include: Mini Earphone Jack, S Meter, 350 Alpha Memories, Carry Handle, Clock, 8 Event Timer, Scan, Sweep, FM AFC, Synchronous Detection, Attenuator, 6/3.5/2.7/14 kHz Selectivity, AF Filter, Record Jack, Dial Lamp, Keypad and LCD Contrast Adjustment.

The CRF-V21 is supplied with: AN-V21 telescopic antenna unit, ACP-88R AC power unit, NP-227 battery, BCA-70 charge tray, antenna cable, protective cover, UPP-21 thermal printer paper and manuals. Operates from 110/120/220/240 VAC. Requires two AA cells for memory retention. 16.25 x 11.25 x 6.75 inches (21 lbs.).

The CRF-V21 is basically an all-in-one Holy Grail portable for those at sea!

@LondonShortwave also shared the following video of the CRF-V12 in operation:

Simply amazing. I love the display–reminds me of the Eton E1. I would expect excellent audio out of this rig as well.

When I checked today, there wasn’t even one CRF-V21 listed on eBay–not even as a completed listing. I imagine they are rare indeed.

Out of curiosity, do any SWLing Post readers have a Sony CRF-V12 in their collection? I would certainly like to add one to mine someday.

Many thanks to my friends @K7al_L3afta and @LondonShortwave for this radio diversion today!

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

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Dr. 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

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.

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:

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The Spectrum Monitor: only $24 for a year’s subscription

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On occasion, the things you enjoy most, you forget to share with your friends. Not sure why this happens, but this is certainly the case with the Spectrum Monitor magazine (TSM). I’m long overdue to properly pitch TSM to my readers, which I feel is an absolute bargain at just $24 per year.

Why? Many of you may recall that it was only July of last year when we learned about the closure of The Monitoring Times magazine. I had always loved the magazine–not only were the management and editors a great group, but the magazine content was some of the best in the communications business when I began writing features and reviews for MT. But the owners of MT, Bob and Judy Grove, were ready to retire; ultimately, they decided to close their magazine down rather than sell it off.

Shortly after the announcement, MT‘s managing editor, Ken Reitz (KS4ZR), decided to make a go of a new publication. Albeit wholly digital, this magazine was to cover the same scope and content depth as MT, and would be known as The Spectrum Monitor (TSM).

In January of this year, TSM launched, and like many SWLing Post readers, I was eager to see if the content met the benchmark MT had set for so many years.

I needn’t have worried. Ken had corralled many excellent contributors, in many cases drawing upon previous writers for MT. And in the past year, I don’t believe it’s a stretch to say that in many respects, TSM not only met that benchmark, but has actually even exceeded it. TSM is now–unquestionably–a good, solid, thoroughly enjoyable publication.

Each issue is packed with topics covering the radio spectrum: shortwave, ham radio, vintage radio, pirate radio, scanning, public service, satellite, AM/medium wave and host of digital/mobile technologies, as well. Really, everything a listener could hope for.

Initially, I had my doubts. I frankly wasn’t sure whether I’d like reading a “digital-only” radio publication, or whether other readers would. I confess to being a bit “old school;” as a radio listener, I like to hold a radio in my hands, to physically tune it; as a reader, I prefer holding a printed publication in hand, to turn the (paper) pages…How would I feel with an e-reader or laptop, instead? Would reading that way feel like work?

But TSM soon swayed me toward the digital as both reader and as a columnist. As a writer, there was less stress on word count. If it was a bit short, or lengthy– as my October column was–I soon found it mattered less. In a digital publication, page count is comparatively irrelevant as long as content is worthwhile and captivating for the reader. And as a reader, I appreciated that the columnists that I was reading would have the freedom to write at length, too.

Secondly, a digital publication gave its writers an opportunity to infuse columns with a multi-media element–something I’d become accustomed to as a blogger here on the SWLing Post. When I published a review of a radio, I could include actual audio clips in the article. If I wrote about pirate radio, for example, I could embed actual pirate radio recordings. Brilliant! And, again, more fun for the reader.

Also, including links or references to external websites is a cinch in a digital format, and quite easy for the reader to check out. Instead of copying a long gangly URL from a printed page, you simply click on a link as you would on a website, such as on this one. Second nature, really.

Finally, in a digital publication, I found writers could use more full-color images in their articles. I really enjoy the addition of the images; they make articles come to life…

So, I soon learned to relax with the e-reader just as I had with the printed Monitoring Times. No pages to turn, but then again, not so different from reading…well, a blog like this. I’ve received excellent feedback from TSM readers, too, many of whom admitted their initial bias against a “digital” magazine had since been withdrawn completely.

I continue to enjoy reading TSM every month. And although–due to time constraints–I’m no longer TSM‘s primary shortwave radio columnist, I still enjoy writing for TSM when time permits, so you will see my reviews and features pop up in TSM now and again.

But why take my word for it? Check it out for yourself–it’s one of the best magazines for the radio enthusiast, digital or print…And at only $24 annual cost, it’s a terrific and affordable last minute Christmas gift for a friend, family member, or–let’s be honest–for yourself.

Afraid to commit to a one year subscription? Individual issues of TSM are available online for $3 each. If you like what you’re reading (you will), you can then purchase a one year subscription, and the cost of your issue will be refunded.

If you’re lucky enough to receive a subscription to TSM in your stocking, I can assure you that you’re in for a real treat. Happy reading!

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VOA Radiogram, 29-30 November 2014: Dim the lights

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(Source: VOA Radiogram)

Flmsg returns this weekend on The Mighty KBC. See details below.

This week on VOA Radiogram, the “surprise mode of the week” becomes the “bonus mode of the week.” Because many of you have problems with the RSID, I will divulge the bonus mode so that you can make manual adjustment if necessary.

Here is the lineup for VOA Radiogram, program 87, 29-30 November 2014, all in MFSK32 centered on 1500 Hz except where indicated:

1:37 Program preview
2:39 Dimming lights to see the night sky*
11:27 Cambodian rice wins “world’s best” title*
19:53 Color photos of 1963 Soviet Union*
26:29 Closing announcements
27:20 Bonus mode of the week: MT63-2000L

Please send reception reports to [email protected]

VOA Radiogram transmission schedule
(all days and times UTC):
Sat 0930-1000 5910 kHz
Sat 1600-1630 17860 kHz
Sun 0230-0300 5745 kHz
Sun 1930-2000 15670 kHz
All via the Edward R. Murrow transmitting station in North Carolina.

The Mighty KBC will transmit a minute of MFSK64 Saturday at about 1230 UTC on 6095 kHz, and Sunday at about 0130 UTC (Saturday 8:30 pm EST) on 7375 kHz. Both frequencies are via Germany. Reports to Eric at themightykbc (at) gmail.com.

This weekend, the MFSK64 transmissions on The Mighty KBC will be in Flmsg format. If you do not have the Flmsg software, download it from the same source as Fldigi: http://w1hkj.com/download.html.

To make Flmsg work with Fldigi, in Fldigi: Fldigi: Configure > Misc > NBEMS > Under “Reception of flmsg files” check both “Open with flmsg” and “Open in browser.” Under that indicate where your Flmsg program is located, for example C:Program Files (x86)\flmsg-2.0.5\flmsg.exe.

If all goes well, the text from The Mighty KBC will pop up on your web browser.

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STF Broadcast #2 Schedule

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(Source: STF Radio International)

STF Radio International
Broadcast #2

November 30 0500-0600 UTC
5110 / 7490 / 7570 / 7730 / 9330 The Americas
9955 The Carribean
17645 Asia
Preshow Warm-up!!
November 30 0400-0500 UTC
7730 Khz The Americas

PLUS! Rebroadcast for EU
November 30, 2014 1600-1700 UTC
6095 kHz EU
“I can see the radio wave.”

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