Category Archives: Digital Modes

SSTV Special Event from the International Space Station on Saturday, October 27

(Source: ARRL News)

Amateur Radio on the International Space Station (ARISS) has scheduled a slow-scan television (SSTV) event to begin on Saturday, October 27, at about 1000 UTC. NASA’s Space Communications and Navigation (SCaN) Department will support the event. SCaN manages NASA’s three most important communications networks — The Space Network (SN), Near-Earth Network (NEN), and the Deep Space Network (DSN). Participants in the SSTV event can qualify for a special endorsement for NASA on the Air (NOTA), celebrating the space agency’s 60th anniversary.

As during past ARISS SSTV events, 12 images will be transmitted. Six will feature SCaN educational activities, while the other six images will commemorate  major NASA anniversaries, including the establishment of NASA and the moon landing. Transmissions are expected to take place on 145.800 MHz using PD-120 SSTV mode. Received images can be posted and viewed online. The event is dependent on other ISS activities, schedules, and crew responsibilities, and the schedule is subject to change at any time.

More information be posted to the AMSAT and ARISS websites as well as to the ARISS-BB, to the ARISS Facebook page, and via Twitter (@ARISS_status).

Click here to read the full article at the ARRL News.

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Stefano invites you to experiment with DRM (Digital Radio Mondiale) over IP

Photo by Sergi Kabrera on Unsplash

Many thanks to SWLing Post contributor, Stefano Mollo (VK6WFM), who writes:

I have been lately experimenting with DRM 30, with the aim of coming up with a cheap solution to get on air for next to no $$$, for small, local broadcasters that would either go pirate on FM or would not go at all due to the impossibility here in Australia to get a proper FM license at a cost that does not involves selling a kidney (or two)!

I am a ham radio operator, so I turned my attention to DRM30; [the DRM application] DReaM has the capability of acting as a transmitter as well, so I started experimenting.

Click here to download DReaM via SourceForge.

I was very successful at transmitting a DRM30 / 10 kHz signal with a $ 0.50 TX module otherwise intended to transmit data with an Arduino. The signal was received with an SDR + HDSDR + Virtual Audio Cable + DReaM in reception mode.

So far, so good; with this experiment I realised that DRM 30 can, in fact, yield excellent quality at ANY frequency (as I used the 433Mhz LIPD range in my experiment) or better said, with any medium, as long as it is linear enough to transport the DRM signal.

I wanted to find a way to show the World – literally – what can be achieved with DReaM in TX mode…for free!!!

So, after some trial and error, I have set up the system below which allows anyone in the World to “tune in” my “DRM30 radio station” and listen to my DRM30/18 kHz signal, in full blown stereo. Quality is exceptional, and just imagine to send DReaM’s signal to a proper transmitter instead of streaming it over the internet ….

So…point your VLC Media Player (on Windows) to stream from:

…then pipe VLC’s output to DReaM’s input via Audio Cable (or any other Virtual Audio Cable you like).

In DReaM, select the audio cable output as the sound card’s signal input device:

Then select L+R as Channel:

Set the sample rate to the highest value:

One more thing you need to set is the “Channel Estimation: Time Interpolation” parameter to Linear; this is very important!

After few seconds you should be able my test signal, in full stereo, streamed from a PC running DReaM in TX mode, whose output is then captured by MB Recaster and streamed to an ICE Cast server I have in the Cloud. Note that no particular configuration was needed on the ICE Cast server, at all.

This is an example of what can be achieved on a solid transmission channel with DRM30 and only 18 kHz bandwidth (i.e. the normal bandwidth of an AM channel).

One can achieve the same exact audio quality using any channel linear enough to transport an 18 kHz wide DRM30 signal. It doesn’t matter the frequency, or the physical medium per se.

[…]My aim with this experiment is not to send DRM over IP; there are much simpler ways or streaming audio over IP.

Rather, my aim is to demonstrate what can be achieved with 18 kHz +DRM30 on any frequency and on any medium (which, could be for example the electrical distribution overhead lines …. just saying …. 🙂 ).

If only the local regulator would support this, instead of enforcing draconian regulations … such as the restriction of just 6 kHz on shortwave.

Please share your thoughts.

Fascinating experiment, Stefano! Thanks for sharing!

Post readers: If you’re in the mood to do a little experiment, let us know if you’re able to decode Stefano’s 18 kHz DRM30 broadcast over IP!  Please comment!

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All-digital AM HD: WWFD’s experiment is attracting attention

(Source: InsideRadio via Ulis K3LU)

All-Digital AM Grabs Automakers’ Interest.

The fate of AM radio in the car dashboard may pass through Frederick, MD. That’s where the latest experiment on an all-digital AM signal is taking place, on Hubbard Radio’s adult alternative “The Gamut” WWFD (820). The project, in conjunction with digital radio developer Xperi and the National Association of Broadcasters’ PILOT program, is already generating interest from carmakers in the U.S and around the world.

The Federal Communications Commission in July approved a proposal to allow WWFD to turn off its analog signal for the next year while remaining an all-digital operation. The aim is to use the real-world environment to conduct experiments designed to improve the all-digital AM service.

WWFD has 4,300-watts day (non-directional) and 430-watts night (directional) and the company proposes to operate with roughly the same output when it goes digital-only, 24-hours a day. Dave Kolesar, Hubbard’s senior engineer overseeing the project, said it’s an ideal station to use for a test case since it’s non-directional by day and directional at night.[…]

The switch has already been flipped and Xperi senior manager of broadcast technologies Mike Raide said preliminary results are encouraging. “We haven’t had any problems with OEM receivers,” he said, noting he drove 70 miles from the transmitter site and still picked up WWFD without any problem. In fact, one DX listener in the Pittsburgh area, roughly 300 miles away, said they were able to hear the station during the daytime. “That’s a testament to how robust all-digital is,” Raide said.[…]

“At a time when we’re all hearing rumors about car manufacturers cutting AM from their factory offerings, something like this could come along and show the auto manufacturers that AM still matters and AM has a digital solution as well,” Kolesar said.[…]

Click here to view the full article at InsideRadio.

In August, I received a strong lock on WWFD in neighboring West Virginia via my car’s built-in HD receiver. The next day, I made this short video of my reception on the Sangean HDR-14 (read review here) in neighboring Germantown, Maryland:

I found that WWFD covered the DC metro area quite well.

Post readers: Do you believe, as this article implies, that AM HD could revitalize the band?

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“Slow Scan Radio” is a new digital program on Channel 292

(Source: Southgate ARC via Mike Hansgen)

New Datamodes programme on BC bands

Starting on Wednesday 25th of July 2018 at 1830 UTC, there will be a new 30 minute programme featuring various datamodes, such as SSTV and some of the more complex and interesting PSK modes.

The programme is called ‘SLOW SCAN RADIO’, and will go out on 6070 kHz AM via the transmitter of German based relay station Channel 292, and should be audible throughout many parts of Europe.

http://www.channel292.de/schedule-for-bookings/

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Bill tunes to WWFD in AM HD

Many thanks to SWLing Post contributor, Bill Mead, who writes:

Thomas, I’m sending you a short clip from WWFD 820 kHz in Frederick, MD. It’s America’s only all-digital station, apparently. They are HD only with a relatively eclectic music format. I’m hearing them at my QTH in Harrisburg, PA, about 80 miles or so north of their transmitter which is 4.3 Kw daytime. I sort of doubt they’ll come in at night when they drop down to 430 watts, but who knows.

My experience with HD on MW is that it can be heard at pretty decent distances under ideal conditions but the slightest bit of interference, a lightning strike or someone switching on the lights for example, and it’ll lose the HD lock.

My HD receiver is a Sony XDR-F1HD. It’s well-known as an excellent FM DX machine. What’s not as well-publicized is that it’s a very decent MW receiver as well. All it needs is a good MW loop antenna directly connected to the AM ANT terminals on the back of the radio.

Click here to view on YouTube.

Excellent!  Thanks for sharing, Bill. I’m passing by Frederick, MD in a couple of weeks and plan to tune to WWFD in both my car and with the Sangean HDR-14.

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