I find this an article I read in Radio World to be absolutely fascinating. It’s called “Radiogram” and it basically is a method of embedding webpage like content within a tone via an shortwave AM broadcast!
No internet connection or special equipment is needed to receive or decode the signal other than a standard shortwave receiver and a computer or smartphone.
Below I’ve copied and pasted the highlights from the full article at http://www.radioworld.com/default.aspx?tabid=75&entryid=10210
..They want to draw attention to VOA Radiogram, a form of international high-frequency broadcasting. Radiogram is a VOA program experimenting with digital text and images via shortwave broadcasting;
Radiogram broadcasts Web content via error-detecting/correcting AM tone modulation, using standardized formats commonly used by ham radio. They say this approach is robust and resistant to interference.
“The user’s ordinary shortwave receiver, tuned to a Radiogram transmission, feeds its audio to a user device. These could include mobile phones, tablets, laptop and desktop computers and the new ARM-based miniature computers and embedded devices. The user device decodes the tones and displays text and imagery despite propagation impairments and intentional interference — and without Internet connection.”
They point out that no hardwire connection is required; putting the radio near the phone or computer is usually sufficient. “By adding a simple audio cable between receiver and user device, however, reception can be silent and covert. No specialized hardware is needed, and the software platform for decoding is long in the public domain.”
The user need not be present to receive content, and essentially receives a web magazine “updated at will and always ready for use” that can be redistributed.
“Naturally, the audio tone transmission can be recorded for later playback. Even when buried well under music or noise, the nearly inaudible recorded broadcast can nevertheless deliver 100% copy upon decode. “
Radiogram’s transmission methods provide text at 120 words per minute, along with images.
“Sent over regular broadcast transmitters (no modifications needed), this approach effectively extends the reach of the transmitter. In other words, the digital text mode will decode in locations where the audible speech over the same transmitter would be too low for aural intelligibility. The audio recorded or captured could be replayed over another transmitter to even further extend the reach of the broadcast.”
Here’s some more information
Here’s some more information and links to youtube videos showing it in action. In the first example it shows a Radiogram sent from North Carolina as it was received and decoded in Japan.
This one included only text, but some of the other examples include images such as logos and photos as well..
http://voaradiogram.net/
Since no special equipment is
Since no special equipment is needed on either end, wouldn’t it also be feasable to experimenting the same proceedure with part 15 AM locally?
Interesting
We should keep an eye on this!
Bruce, DOGRADIO
I’ve been trying to find more
I’ve been trying to find more information about this.. If I had a shortwave receiver I’d be all over this thing!
To decode and read the VOA Radiogram text and image transmissions, you will need the following items:
1. A shortwave radio. The radio does not need to have single sideband (SSB) capability. Even if you do have SSB capability, listening in the AM setting will probably work best.
2. A basic personal computer. It does not have to be particularly powerful.
3. A patch cord from the audio output of the radio to the audio input of the PC. This is usually from the earphone jack of the radio to the microphone jack of the PC.
4. Free software to decode the digital text. This includes the free Fldigi program http://www.w1hkj.com/ (also download companion Flmsg and Flamp programs), as well as MixW, MultiPSK, DM780 (part of Ham Radio Deluxe), and others.
VOA Radiogram transmission schedule
(all days and times UTC):
Sat 0930-1000 5745 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.
More information at http://voaradiogram.net/
Under Study
I don’t mean that I’m an understudy, which is someone being tutored by a smart teacher, but the subject of RadioGrams is under study here at Worldround.
There are a few links provided by Rich Powers I haven’t yet seen, but the one I did see had this warbly tone which would certainly annoy most listeners, only to see some slow “texting” or something like a sluggish web browser.
Yet, I think I read that the RadiGram tone can be “buried” in the audio and pass unheard, while it texts and browses.
What would be the use for it, assuming the audience would set up to receive the RadioGrams?
Why ask why?… Why not?
“What would be the use for it, assuming the audience would set up to receive the RadioGrams?”
Good question Carl. I not sure. I just think it’s cool capabilty!
The following factors is the closest things I’ve been able to gather which might begin to provide an explaination of an actual purpose..
… Just prior to VOA launching this experimentation about year ago, this blog: http://swaus.blogspot.com/2013/03/voice-of-america-radiogram.html described it’s purpose as such:
The Voice of America is set to launch a new communication service on shortwave radio with interesting implications for information flow in crisis situations or under repressive regimes…
..The idea behind Radiogram is to facilitate the spread of vital information in areas of the world where communications are restricted. Shortwave provides massive range – and the technology works remarkably well even in conditions where reception of regular programs are degraded, including jamming…
Some noted advantages as compiled from other sources:
… The content is retreivable without the need of internet connection.
… The signal carrying the text is very resistant to interference and can still be retrieved and decoded at a greater range even after the accompaning audio has faded to static.
… The user has no need to be present for the transmission, one only has to set it up and a updated “web magazine” will be there complete and waiting to be read, printed and/or redistributed. “Even when buried well under music or noise, the nearly inaudible recorded broadcast can nevertheless deliver 100% copy upon decode.”
The writer of the Radio World blog recomends here http://swling.com/blog/2014/03/dear-bbg-take-note-of-the-radiogram/ that Voa should:
1. Capitalize on Radiogram as a circumvention tool, readily consumable by mobile devices. It should integrate Radiogram into its media strategy and networks.
2. Retain, but reconfigure as necessary its HF facilities in view of the potentially lower costs and greater efficiency of Radiogram when compared to conventional sound broadcasting.
3. Support the development and wide distribution of simple, usable, open-source Radiogram decoding applications for popular mobile devices and platforms (Android, iOS, Windows, Mac, Linux), derived from the free Fldigi software used worldwide.
… The nearly inaudible signal is easily heard by canines, who in turn will bark, thus convienatly alerting that a new message has just arrived. (ok, I made that up)
Premature Approval Granted
I like it, and would like to get it set up and running, we can always work out the purpose later on. I might start RadioGramming this thread!
Radio technologies that permit sending multiple programs on a single carrier have always fascinated me, and now that we can stack two distinct events on an AM signal, maybe we can add a third hidden transmission.
Radiogramming
Today’s Happy Station Show with Keith Perron had a Radiogram moment.
Keith played an example of a Radiogram encoded transmission, and said he is experimenting with it on upcoming shortwave transmissions from PCJ Media, which is heard from WRMI and other international transmitters.
http://www.pcjmedia.com
I am now ready to go with part 15 AM Radiograms as follows:
1. Text with info about “Currently playing”;
2. Text about “Coming up next”;
3. News crawls just like CNN;
4. Promotions for anything;
5. Nice pictures of things.
What has NOT been described in detail is how the Radiograms are generated. Yes, it was mentioned that common HAM techniques are used, so let’s hear more about that part of it, please, thank you.
MORE TO SAY
Finding that I still have 7-minutes on the meter, and knowing that we get 3-meters, I just had a huge brain thaw:
Why limit our part 15 small-thoughts to AM radio? Why not stream Radiograms right along with our online radio stations?
Talk about leading the NSA on a very merry chase.
Even though titles already get sent out with streaming radio, why not have a second Radiogram channel, maybe put commercial messages on there and sell the space as The Subliminal Plan.
What has NOT been described
What has NOT been described in detail is how the Radiograms are generated. Yes, it was mentioned that common HAM techniques are used, so let’s hear more about that part of it, please, thank you.
Carl,a few nights ago I had searched around.. rather stumbled around looking for an answer to that question.. I first just searched “radiograms”, but that was no help, because evidently the VOA Radiograms are not at all the same as the radiograms described to be common practice amongst Hams, which basically just entail relaying a message from one ham to another until it eventually reaches an intended recipient.
I tried searching all different ways without much luck.The only thing I found was a few pdfs which appeared to address the issue:
Implementation of ETAS (Embedding Text in Audio Signal) Model to Ensure Secrecy – http://www.enggjournals.com/ijcse/doc/IJCSE10-02-04-85.pdf
A Novel Approach for Embedding Text in Audio to Ensure Secrecy – http://www.ijcsit.com/docs/Volume%202/vol2issue4/ijcsit2011020445.pdf
Enhanced Data Hiding Model in Audio to Ensure Secrecy -ijeit.com/vol%202/Issue%209/IJEIT1412201303_18.pdf
I bookmarked them for the hell of it, but did not mention them because frankly, they didn’t appear to be of any help at all.
However, it wasn’t until a few moments ago that it suddenly occured to me that I’ve been going about it in the wrong way.. The article mentions that the software used to decode has been in the public domain for a long time, and even provides a link where to download it: http://www.w1hkj.com/
That’s where my search should have begun!
Well, there are numerous programs available there, which I’ve just now glanced over, but from the initial lookover; the Fldigi program (same as the one shown in the videos receiving transmissions) is only capable or receiving. But the program called Flarg is “capable of transmitting and receiving frames of ARQ data via fldigi”.. I don’t know exactly what that means yet, but it sounds like a start.
Like I said there’s also several other such programs there.. Have you looked into any of them yet?
Why limit our part 15 small-thoughts to AM radio? Why not stream Radiograms right along with our online radio stations?
Believe it or not, simular thought crossed my mind as well. I have no specific ideas on how (or if) implementing embeded text and/or images into part 15 or streaming broadcast could be of any use, but I’d like to experment at least – just so I would know how to do it, in case some brilliant idea on what way to utilize the capability should arise.
put commercial messages on there and sell the space as The Subliminal Plan.
Great!..
Excellent Hunting Expedition
Richard Powers, you are to part 15 what Morse was to code.
I didn’t look for a transmission method for Radiograms because I didn’t know what to look for. Your discovery that it might be software and not hardware is the official clue of the moment.
Perhaps we can learn more from Keith Perron at PCJ Media. He is very receptive to e-mail contact, or he might mention something on his programs.
You obviously were first to think of putting Radiograms together with web streams, so you are the father of Webgrams or whatever your name will be. But I am the second person ever, in all history, to think of it.
Also, add to my list of uses, the Radiogram should default to an image of the station Logo with I.D.
Don’t be riduculous.. I wasn
Don’t be riduculous.. I wasn’t the first to think of anything, nor to be the father of webgrams or whatever.. As a matter of fact, I am now, at least for the time being, prepared to put thoughts of experimentation with this thing totally aside.
I was in hopes of something a little more cut and dry; like install a software to compress and send, and another software to decode.. Although it does appear to be exactly is going on – it’s striking me to be rather complicated…
I’ve read through the softwares and proceedures there, and it appears evident that everything needed to accomplish the objective is indeed provided on those pages, including the softwares and details of setup. Yes, all the answers are there.. But.. It seems the presentation of the information is suited for those who already are experienced with the proceedures.
Sure, I could figure it out, so could you, or most anyone else. But unless I come across a simple step 1 step 2 step 3.. tutorial or something, I prefer to just leave it alone for now.
The whole idea of it is cool, but I get the impression there would be a lot of time and effort involved just for the sake of a novelty.
How about you dive in, and once you got it all figured out, write us a simple tutorial. How bout it? You’ll be the father of the LowPowerGram!
It’s On the List
Alright. I understand. Sure, I’ll take over until you’re ready to take it back.
I have put it on my list.
As it stands, I should get around to it in 400 years.