VOA Radiogram

Radio Australia MFSK tests are successful

Sat, 18 May 2013 07:36:00 -0400

The first Radio Australia test of digital text was successful. It was 18 May 2013, 0830-0835 UTC on 7410 and 11945 kHz.

I saw reports of 100% copy on 11945 from listeners in Germany and Kansas City: pretty good range for one transmitter and one frequency.

In norther Virginia, I listened and decoded on 7410 kHz because it was the signal coming in less well. Despite a fair-to-poor signal level, and a Cuban jammer on adjacent 7405 (listen to and decode audio here), copy of both MFSK16 and MFSK32 text was 100%.

Because the broadcast started a bit late, it ended just as the MFSK32 image was beginning. After the text, Radio Australia switched back to a sporting event. The audio gives you an idea of how a voice broadcast sounds given the same reception conditions.

Roger in Petersberg, Germany, provides this image of his reception on 11945 kHz.

Peter Marks in Sydney wrote this blog post about the Radio Australia digital text test, and he produced this YouTube video.

The MFSK32 image was included during the transmission at 1230-1235 UTC on 9580 kHz. This is what it looked like in northern Virginia. A bit rugged but not bad for half way around the word:

My text copy on 9580 kHz was 100%. This is what it looked like when MFSK16 switched over to MFSK32:

Reception by Omar Alfredo Ortiz in Bogota, Colombia, 18 May 2013 at 0830 UTC on 11945 kHz in this YouTube video.

More SSTV on VOA Radiogram May 18 and 19

Thu, 16 May 2013 11:42:54 -0400

On VOA Radiogram for the weekend on 18 and 19 May, we will continue to experiment with images. In fact, we will transmit the same picture three ways: in two SSTV modes and then as an MFSK32 image. Bring something to read, or an electronics project, because these picture transmissions will take 4 to 5 minutes each.

To decode the SSTV modes, several software programs are available. They include the RX-SSTV (receive only) from http://users.belgacom.net/hamradio/rxsstv.htm , MMSSTV from http://hamsoft.ca/pages/mmsstv.php , and Digital Master 780, part of the Ham Radio Deluxe suite, from http://www.hrdsoftwarellc.com .

Before the images will be two VOA news stories in MFSK32 text, with the usual center audio frequency of 1500 Hz. The second story is in French, as we continue to determine if accented letters appear correctly on your display.

To view accented characters in Fldigi: Configure > Colors & Fonts > next to Select Char Set, select UTF-8. To keep your selection of UTF-8, under Configuration, click Save Config.

Here is the lineup for VOA Radiogram the weekend on 18 and 19 May:

2:55 MFSK16 Program preview

1:59 MFSK32 VOA News in English

4:03 MFSK32 VOA News in French

1:07 MFSK16 Intro to SSTV transmissions

4:31 Scottie DX SSTV

:10 Tone (to give you time to save your Scottie DX image)

5:08 Pasokon P5 SSTV

:25 MFSK16 intro to MFSK32 image

4:07 MFSK32 image

1:10 MFSK16 closing announcements

1:22 Surprise mode of the week (mixes somewhat with the closing music)

On VOA Radiogram during the weekend of 25-26 May, we will experiment with the Easypal digital SSTV mode, comparing it to MFSK32. Please download Easypal from http://vk4aes.com . Easypal images are transmitted by radio amateurs on 14233 kHz.

VOA Radiogram transmission schedule

(all days and times UTC)

Sat 1600-1630 17860 kHz

Sun 0230-0300 5745 kHz

Sun 1300-1330 6095 kHz

Sun 1930-2000 15670 kHz

All via the Edward R. Murrow transmitting station in North Carolina.

More Hell this weekend on The Mighty KBC

Thu, 16 May 2013 09:29:11 -0400

The Mighty KBC will transmit the Hell 80 mode at about 0133 UTC on Sunday 19 May (9:33 pm EDT Saturday), centered on 1500 Hz. This is during its North America broadcast Sunday at 0000-0200 UTC on 9925 kHz via Nauen, Germany.

At just before 0200 UTC, images in MFSK32 will be centered on 1000 and 2000 Hz.

Radio Australia digital text and image May 18 and 19

Thu, 16 May 2013 08:56:00 -0400

For the first time, Radio Australia will broadcast digital text and images. This will be Saturday 18 May and Sunday 19 May 2013.

UTC               Frequency (kHz)   Target

0830-0835     7410 & 11945        south-west Pacific

1230-1235     9580 & 12095*        south Pacific

*Glenn Hauser believes this should actually be 12065

As is characteristic of shortwave, reception outside the nominal target areas is likely.

Each five-minute broadcast will include:

:34 RA tuning signal (still Waltzing Matilda?)
:05 Tone 1500 Hz
1:42 MFSK16 text
1:42 MFSK32 text
:55 MFSK32 image

All modes are centered on 1500 Hz

The Radio Australia digital transmissions can be received on any shortwave, even if it does not have single sideband capability. Patch audio from the radio to a personal computer, and use software to decode the modes. For more information, see how to decode the modes.

Scottie DX SSTV images on VOA Radiogram

Sun, 12 May 2013 17:35:00 -0400

Our experiment with the Scottie DX SSTV mode over the weekend of May 11-12 brought mixed results.

There were some impressively clear images. The picture is a shortwave curtain antenna in North Carolina of the type used to transmit this SSTV picture.

For example, this from Hugo in Veurne, Belgium, 15670 kHz:

And from Marco, IK0DWN, in Rome, 17860 kHz:

And from Harald, DG0OCS, in Thuringia, Germany, 17860:

And from Mauno in Finland on 15670 kHz:

From Michael in Eschborn, Germany, on 17860:

From Tarmo, ES5NHC, in Estonia, a more impressionist SSTV image on 17860:

And from Bruce, N0NHP, in Colorado, a more Dadaist SSTV image on 17860:

VOA Radiogram, May 4-5, via shortwave, then via YouTube

Fri, 10 May 2013 08:14:00 -0400

Four YouTube videos demonstrate the reception and decoding of VOA Radiogram from the weekend of May 4 and 5 2013.

Two are from Andy, N9VT, near Fredericksburg, Virginia…

5745 kHz:

www.youtube.com/watch?v=fjqCzhLPYH8

6095 kHz:

www.youtube.com/watch?v=dTioSlwgcVw

Hugh Stegman of Monitoring Times Utility World shows how Flamp worked during his reception in California on 5745 kHz:

www.youtube.com/watch?v=1Q0k9uFykvk

Craig, AV4M, in Tennessee, produced this video of the entire broadcast on 15670:

www.youtube.com/watch?v=a3qFP6WD4Nk

VOA Radiogram images as received in Slovakia

Fri, 10 May 2013 07:43:49 -0400

Dezider, OM5NA, in Slovakia, provided these screenshots of his MFSK32 image reception on 4 and 5 May 2013, on 17860 vs 15679 kHz:

Audio of Dezider’s reception of the entire VOA Radiogram on 15670 kHz is available at his SoundCloud page.

VOA Radiogram: The rule of FUM (Fastest Usable Mode)

Mon, 29 Apr 2013 10:44:00 -0400

Thanks to everyone who sent reception reports, screenshot, audio samples, and other attachments after listening to VOA Radiogram during the weekend of April 27-28.

After six weeks of experimenting with digital text modes, I think we can conclude that the PSK modes are good, MT63, Olivia, and Thor are better, but MFSK remains the best.

We can coin a new acronym: FUM — Fastest Usable Mode. It appears that these would be our FUMs:

MFSK16 (58 wpm): when poor reception conditions are expected
MFSK32 (120 wpm): when fair reception conditions are expected
MFSK64 (240 wpm): when good reception conditions are expected
MFSK128 (480 wpm): when perfect reception conditions are expected (eg local FM or AM)

During reception of the Sunday 1930 UTC broadcast on 15670 kHz, I experienced a poor signal (being in the skip zone), moderate fading, and local noise. Excellent conditions to test digital text modes. This audio excerpt shows how MFSK16 provided a perfect decode even in these conditions. The Fldigi readout is below, showing MFSK64 on top, MFSK16 on the bottom:

VOA Radiogram: Flamp worked. Except when it didn't work.

Mon, 29 Apr 2013 07:40:00 -0400

In the April 27-28 VOA Radiogram, a VOA news story was transmitted using Flamp, a program that accompanies Fldigi. Flamp divides text or any type of file into a certain number of blocks, each with a certain number of characters. Then it transmits the file more than once, with subsequent transmissions filling in any blocks that did not have the correct number of characters during the first pass.

To test Flamp, I used the MFSK128 mode. This mode is very fast, thus prone to errors, hence useful for experimentation with Flamp. My own reception of VOA Radiogram on April 28 at 1300 UTC on 6095 kHz provided a textbook example of how Flamp works. After the first of two transmissions, three blocks were missing, i.e. rejected because they had the wrong number of characters :

Then all of the text was transmitted again. Flamp filled in the blocks that were missing:

The result was a perfect html file that could be saved, or pasted to a text editor, and opened in a web browser. The result looked like this:

Many listeners reported reception of a high percentage of the blocks after the second pass, but without 100% of the blocks received, the file could not be opened. This suggests that, next weekend, I should set Flamp to transmit three times. A 3X transmission of Flamp will take more time, so the question for us is whether the slower but more robust MFSK64 transmitted once is a better solution than MFSK128 transmitted multiple times.

For some listeners, Flamp did not work at all. One cause for this is that the beginning code was not not received correctly (“header corruption”). It should look like this:

Any actual use of the Flamp concept in international broadcasting would require a software application that simplifies the process and places it in the background.

A solution to uneven line breaks

Sat, 27 Apr 2013 06:58:55 -0400

I’ve noticed in the text “dumps” sent by many VOA Radiogram listeners that the line breaks are uneven. This happens when the received text is copied from Fldigi or other decoding software and pasted into a text editor or word processor.

The problem was that I was pasting text with no line breaks into the Fldigi output window. The solution, suggested to me by Christopher, K6FIB, is to force line breaks at the traditional (from the days of punched cards) 80 characters per line:

I will try to remember to use line breaks from now on. If decoding of digital text via shortwave on mobile devices becomes common, we might have to adopt a smaller number of characters per line.

Kim

VOA Radiogram: YouTube from Italy of decoding on 17860 kHz

Fri, 26 Apr 2013 08:49:00 -0400

IK1RKU in northern Italy provided this excellent YouTube video of the entire VOA Radiogram transmission on 20 April 2013, 1600-1630 UTC, on 17860 kHz:

www.youtube.com/watch?v=Fnw4yu4SGbo

And another YouTube recording of an entire VOA Radiogram by Andy, N9VT, in Fredericksburg, Virginia. This is from 21 April 2013, 0230-0300 UTC, on 5745 kHz. Reception quality was obviously not a problem:

http://youtu.be/iPMZfPjl16Y

For Hugh Stegman, of Monitoring Times Utility World, reception on 5745 kHz was not as good, but he still had fairly good copy of the very fast MFSK128 mode, as seen in his YouTube video:

www.youtube.com/watch?v=6hYYo7yT_gc

VOA Radiogram for April 27/28 includes Thor50x2, PSK63F, and Flamp

Thu, 25 Apr 2013 03:50:00 -0400

Apologies for not updating this website since the April 20/21 VOA Radiogram. I have been diverted by deadlines connected to my other full-time job, audience research analyst for the International Broadcasting Bureau.

Thanks to all who sent reception reports, screenshots, audio samples, and other materials from the past weekend’s program. MFSK held off a challenge from the Thor modes and remains the most successful of the modes we have tested.

However, because your producer omitted the Thor 50x2 mode — a mode that might prove to be robust — from that program, VOA Radiogram on April 27/28 will include a “make good” transmission of Thor 50x2. And a transmission of Thor 50x1 for comparison.

There will also be a transmission of the PSK63F mode. This rather slow mode performed well during VOA Radiogram 1, but we only gave it a minute. There will be a longer transmission of PSK63F this weekend to allow a better evaluation.

The last text transmission this weekend will be in the Flamp format. If you don’t already have it, please download Flamp from www.w1hkj.com. Flamp divides a text file into several blocks, each with a specific number of characters. If any block is received without the correct number of characters, that block is rejected. The missing block can be picked up during the repeat transmission. Flamp might be useful for those text transmissions that are received at about 90% copy, when occasional deep fades prevent 100% copy.

These notes about Flamp:

In Flamp, under Configure, check both of the Auto sync boxes.
Flamp should be running when the news item in Flamp format is transmitted. It does not turn on automatically when a Flamp transmission occurs.
At the end of the first or second transmission, you will see the VOA news story as a html file. Save that file and open it in your browser. It will not pop up automatically like Flmsg.

Here is the lineup for the April 27/28 VOA Radiogram:

MFSK16 (58 wpm) program preview
PSK63F (55 wpm), 2:50
MFSK32 text (120 wpm) and image, 4:28
Thor50x1 (180wpm), 1:48
Thor50x2 (180wpm), 1:46
MFSK64 (240 wpm), 2:16
MFSK128* in Flamp X2 format, 3:46
MFSK32 image

*Probably a good idea to set the MFSK128 mode manually rather than depend on the RSID

All modes will be centered on 1500 Hz.

Each mode will be introduced by a brief MFSK16 transmission, same as last weekend.

Please send reception reports to radiogram@voanews.com

Twitter: @VOARadiogram

VOA Radiogram transmission schedule
(all days and times UTC)
Sat 1600-1630 17860 kHz
Sun 0230-0300 5745 kHz
Sun 1300-1330 6095 kHz
Sun 1930-2000 15670 kHz
All via the Edward R. Murrow transmitting station in North Carolina.

Kim

Thor 50x2 this weekend on The Mighty KBC

Thu, 25 Apr 2013 02:44:14 -0400

The Mighty KBC, based in the Netherlands and transmitting via Germany, will include digital text modes in its North America broadcast, Sunday 28 April at 0000-0200 UTC (Saturday evening 8-10 pm EDT) on 7375 kHz.

At about 0133 UTC, the Thor 50x2 mode will be centered on 1500 Hz. At just before 0200 UTC, MFSK32 text will be centered on 1000 Hz, and an MFSK32 image on 2000 Hz.

On 5 May, The Mighty KBC will change to 9925 kHz for its North America broadcast.

The results so far

Fri, 19 Apr 2013 11:06:00 -0400

Thanks to everyone who has sent reception reports, audio samples, screenshots, and other interesting materials. After the program on the weekend of April 13-14, featuring the Olivia modes, we heard from listeners in Austria, Belgium, Canada (BC and Ontario), Colombia, Finland, France, Germany, Italy, Russia, Sweden, UK, and Ukraine, as well as from the US states of Arizona, Arkansas, California, Colorado, Georgia, Iowa, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Nebraska, New Jersey, North Carolina, Ohio, Oregon, South Carolina, Tennessee, Texas and Virginia.

The results, after five weekends of VOA Radiogram, indicate that, for use in analog amplitude modulated shortwave broadcasting, the PSK modes are good, the MT63 and Olivia modes very good, and the MFSK modes are excellent. MFSK has so far outperformed the other families of modes.

QSL cards

The process of producing and printing the QSL cars is moving along slowly. If you requested a QSL card, it will be sent eventually. Thanks for your patience.

VOA Radiogram transmission schedule
(all days and times UTC)
Sat 1600-1630 17860 kHz
Sun 0230-0300 5745 kHz
Sun 1300-1330 6095 kHz
Sun 1930-2000 15670 kHz
All via the Edward R. Murrow transmitting station in North Carolina.

Below is a screenshot of Olivia 32-2000 made last weekend by Omar Alfredo Ortiz in Colombia:

VOA Radiogram as received in Bogotá

Sun, 14 Apr 2013 09:21:00 -0400

Omar Alfredo Ortiz in Bogotá, Colombia offers this recording of VOA Radiogram, 14 April 2013, 0230-0300 UTC, on 5745 kHz. You can do your decoding from Omar’s audio.

We also like Omar’s keywords:

VOA Radiogram: YouTube video of the 1600 UTC broadcast

Sat, 13 Apr 2013 23:51:00 -0400

Hugh Stegman, editor of the Utility World column for Monitoring Times magazine, produced this YouTube video of his reception of the final ten minutes of the 1600 UTC broadcast of VOA Radiogram on 13 April 2013, 17860 kHz. Hugh is in California.

And from ik1rku in Italy, this YouTube video of Olivia 16-1000 versus Nelson Riddle on 17860 kHz

VOA Radiogram: Good decodes from marginal reception in Poland

Thu, 11 Apr 2013 13:46:00 -0400

Tomak in Krakow, Poland, does not have his digital decoding software working yet, but he did kindly send an mp3 audio file of his reception on 6 April 2013 at 1600 UTC on 17860 kHz.

We decoded the digital text from his audio file. Kim’s voice is barely intelligible, but the MT63-500 was decoded 100%, and the MFSK16 preceding it nearly so, despite deep fades on both text transmissions.

VOA Radiogram: Some details about the transmitters and antennas

Wed, 10 Apr 2013 12:32:00 -0400

In response to questions about the transmission of VOA Radiogram from the Edward R. Murrow Transmitting Station in North Carolina, here are some details.

What kind of transmitter is used?

We are using GE 4BT250A1 250-kW transmitters for the VOA Radiogram programs. It is one of the original transmitters installed at the station in 1962.

What is the actual transmitted power?

The transmitter output power is 80 kW.

What type of antennas are used?

The 5745 kHz and 6095 kHz programs are using a simple dipole with a bearing of 10 and 190 deg:

The 17860 kHz and 15670 kHz programs are using a curtain antenna with a bearing of 45 degrees, This antenna has a forward gain of about 17 dB:

Any other interesting details?

There is no audio processing used in the audio chain between the program source and the transmitter for the Radiogram program.

There is less than 1 dB of loss between the transmitter and the antenna.

See also BBG press release, 2 May 2012, with a link to a video about the transmitting station.

VOA Radiogram: More YouTube videos from Slovakia

Tue, 09 Apr 2013 14:07:00 -0400

Dezider Monoš, OM5NA, in the Slovak Republic has again produced YouTube videos of his VOA Radiogram decodes. These are from 7 April 2013, 1930 UTC, on 15670 kHz.

MFSK16:

youtu.be/FzjEotUuvX4

MT63-1000 (long):

youtu.be/FzjEotUuvX4?t=8m50s

MFSK64:

youtu.be/FzjEotUuvX4?t=11m40s

MT63-2000 (long):

youtu.be/FzjEotUuvX4?t=14m

MFSK32 image:

youtu.be/FzjEotUuvX4?t=22m20s

VOA Radiogram: Near-antipodal decode of MFSK received in Indonesia

Sun, 07 Apr 2013 08:01:00 -0400

This audio sent by John in Depok, Indonesia, provided a perfect decode of MFSK16 and nearly perfect decode of MFSK32. (Note that the voice portion of the broadcast was mostly unintelligible.) MT63-500 did not decode at all. Depok is 16700 km from the IBB shortwave transmitting station in North Carolina. Given the time and frequency, however, John’s reception was probably via the long path: 23300 km. At this distance, the RSIDs don’t work, so set mode and audio frequency manually.