Thursday, February 27, 2014

X4.9 Flare is Cycle 24's 3rd Largest

At 0049 UTC February 25, returning Active Region 1967 (since renumbered AR1990) produced a strong X4.9 x-ray flare with radio sweeps and coronal mass ejection.  A proton storm began soon after. 

Most CME was directed off into space, and it was slow arriving. This planet did experience a moderate bow shock last night, causing a G2 level geomagnetic storm.  Europe experienced some truly amazing auroral displays from this storm, which is now apparently subsiding. 




Polar absorption of radio signals has been quite high for several days now, though low band VHF skip has remained strong around 30-33 MHz at mid-day when illumination of the F2 region is at maximum.  Here in California, copyable signals have come from the Northeastern, Mid-Atlantic, Midwestern, and South Central United States.

Region 1990, formerly region 1967. and before that region 1944, has showed remarkable longevity.  This is its third trip across the Earth-facing solar disk, and it's still making significant flares despite showing signs of magnetic decay.

VOA Radiogram (with big Olivia test) for March 1-2

From Kim Andrew Elliott:

Hello friends,

This weekend on VOA Radiogram, in addition to our usual MFSK32, we will conduct experiments with Olivia at different speeds.

In general, the Olivia modes are too slow for broadcasting. However, we should keep in mind that text via shortwave can be received unattended, for later retrieval, making speed less of an issue. Furthermore, the Olivia modes might be more capable of overcoming co-channel interference than our usual MFSK modes.

The speed of the Olivia modes increases as 1) bandwidth increases and 2) the number of tones decreases. However, as the number of tones decreases, the robustness of the mode, i.e. the ability to decode in difficult reception conditions, decreases.

On our shortwave broadcast channel, we will use the maximum 2000 Hz bandwidth. We will transmit about three minutes of content in each of Olivia 64-2000 (29 wpm), 32-2000 (48 wpm), 16-2000 (76 wpm), and 8-2000 (104 wpm). As the number of tones decreases, and the Olivia modes become faster, how much does performance deteriorate?  

There are RSIDs for each of these Olivia modes. If you change modes manually, you will have to use the Custom menu for the 32-, 16-, and 8-tone versions. Even if the signal is so bad that you can barely hear it, change the modes manually at the appointed time, and you might see the text. Because of latency in the Olivia modes, text will not begin to display until a few seconds after the tones begin.

Here is the lineup for VOA Radiogram, program 48, 1-2 March 2014:

1:34  MFSK32: Program preview (now)
2:48  MFSK32: Introduction to Olivia experiment
4:35  Olivia 64-2000: Excerpt of VOA News story
8:29  Olivia 32-2000: Excerpt from same VOA News story
12:02  Olivia 16-2000: Excerpt from same VOA News story
15:17  Olivia 8-2000: Excerpt from same VOA News story
18:23  MFSK32: Hospital machinist, with image
26:07  MFSK32: Closing announcements

Please send reception reports to radiogram@voanews.com

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.

MFSK image preambles

Last weekend's VOA Radiogram, program 47, brought good decoding results in many parts of the world. One problem noticed by some listeners is that if the preamble to an MFSK image is not received correctly, none of the picture is visible. At voaradiogram.net, I will post mp3 audio of both of this weekend's images. You can "borrow" the preamble from the mp3 recording and "graft" it into a recording of your reception of VOA Radiogram 48.

The 0930 UTC broadcast

The new broadcast Saturday at 0930-1000 on 5745 kHz is becoming very difficult to hear in Europe as we approach spring (although it doesn't feel like spring here in the USA). I was hoping for reports of this broadcast from the Asia-Pacific region, but so far have received none. This past weekend, I did receive my first report from New Zealand, but it was for the transmission Sunday at 1930-2000 UTC on 15670 kHz -- apparently via a very long path from North Carolina.  

The 0930 UTC broadcast does provide very good reception to the North American west coast, so if you live in western North America, try unattended reception while you sleep. 
[Correct! This is usually the best sked here.  Signals are strong and the frequent appearances of the Akrotiri radar do not bother them in the least.  The images have less noise, though (alas) they have more multipath. -Hugh]

In the next few weeks, we will probably change this broadcast to another time and frequency. This might be Sunday at 1400 UTC on a higher frequency receivable in Europe and perhaps farther east.

MFSK64 on The Mighty KBC

The Mighty KBC will transmit another minute of MFSK64 Saturday at about 1230 UTC on 6095 kHz, and Sunday at about 0130 UTC (Saturday evening 8:30 pm EST) on 7375 kHz. Reports to Eric at themightykbc@gmail.com . The Mighty KBC schedule and other information are at kbcradio.eu.

I'll now begin answering your reports from last weekend. I hope to hear from you this weekend.

Kim

Kim Andrew Elliott
Producer and Presenter

VOA Radiogram
radiogram@voanews.com
Twitter: @VOARadiogram

Saturday, February 22, 2014

31.65 MHz: Strangest Noise Yet

Previous solar peaks saw a lot of very baffling and intriguing noises via low-VHF skip. This stuff really appeals to hard core radio geeks.  Nothing like a new noise to make things interesting.

This go-round it's been pretty quiet. I think the reasons are lower solar activity and fewer stations using this largely vacated band.

On February 22, a fairly interesting noise appeared. Superficially it looked like a backward squiggle.  The classic squiggle appears to be caused by industrial RF welding and heating equipment, and it always goes downward.  This one went upward.






Notice the more normal squiggles on the frequency. When there's propagation, these appear all over the band from 30 to at least 33 MHz.

Lately I've been listening to "over 30" squiggles. They're not very squiggly at all.  They tend to be wider than those found on the 10-11 meter band. When received in FM, they make a low, purposeful growl at 50 or 60 Hz, depending on the power line frequency in the country of origin. Here's a typical audio plot right at the time the squiggle crossed the radio passband:



It's not known for sure why the power line frequency would appear, but there are several fairly obvious reasons for it.

The reverse squiggle in question, however, sounded different.  It occasionally made a vocal sound when crossing the radio passband. I decided that I needed to hear more of it.  I started using the SDR to track the signal, in FM mode, as it went upward.

This was not easy, but practice made perfect. Again and again, I chased this across the SDR screen.  Now you know how I spent a perfectly nice Saturday when I could have been engaging in healthy outdoor activity.  Oh well.

Tracking it produces something that has to have started as a voice radio transmission. At times, one hears the exact cadence and audio response typical of Spanish speakers using the "freeband" below 10 meter amateur. A couple of especially good tracking jobs even gave evidence of an echo box in use.

No point posting links to sound files, since these would still sound like weird QRM.  Rest assured, however, that they do NOT sound like industrial machinery.  Here's the recovered waveform, minus as much of the noise as can be removed without changing the signal.



The waveform envelope is very much like male human speech.  So are the frequencies heard. It's just zero intelligibility in anyone's language.

Cause?  I suspect a spur (spurious emission), though it could be some kind of weird intermod with "real" squiggles.

Dizzy stuff, this.

Friday, February 21, 2014

VOA Radiogram for February 22-23

from Kim Andrew Elliott:
 
Hello friends,

Last weekend's experiment with the simultaneous transmission of MFSK32 text and an MFSK64 image was fairly successful. We still need to determine the best combination of modes and audio frequencies for simultaneous text and image transmissions.

This weekend we will resume more conventional sequential text and image transmissions. MFSK32, MFSK64L, and MFSK64 will be used.

Here is the lineup for VOA Radiogram, 22-23 February 2014, program 47:

 1:40  MFSK32: Program preview
 2:55  MFSK32: Greetings to WinteRFest in Iowa, with images
 6:03  MFSK32: Winter SWL Fest forums, with image
 7:24  MFSK32: Lasers for space communication, with image
12:09  MFSK64L: Restrictions on Turkish media, with MFSK64 image
19:19  MFSK64: Independent bookstores in USA, with image
26:35  MFSK32: Closing announcements

Please send reception reports to radiogram@voanews.com


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.


The Mighty KBC, with studios in the Netherlands but leased transmitters in Germany, will transmit a minute of MFSK64 Saturday at about 1230 UTC on 6095 kHz, and again Sunday at about 0130 UTC (Saturday evening 8:30 pm EST) on 7375 kHz. The 6095 kHz is usually not audible in North America except via this SDR receiver in the Netherlands:
 http://websdr.ewi.utwente.nl:8901/ .

Please send reception reports to Eric at themightykbc@gmail.com.



The Winter SWL Fest will be 14-15 March 2014, near Philadelphia. I will be there to demonstrate VOA Radiogram and the decoding of text and images from shortwave broadcast. Information at swlfest.com.


With VOA Radiogram program 47 now produced, I will begin answering your emails.


Kim


Kim Andrew Elliott
Producer and Presenter
VOA Radiogram
voaradiogram.net

Thursday, February 13, 2014

VOA Radiogram for Feb. 15-16

VOA Radiogram continues to experiment with simultaneous text and image transmission. It makes a godawful racket on the audio channel, but it works.  Here is the image transmitted last week, cleaned up by combining pixels from the upper and lower sidebands as sent on 5745 kHz.




From Kim Andrew Elliott:

Hello friends,

Happy World Radio Day. See http://www.worldradioday.org/

About 25 cm of snow is on the ground here in Arlington, Virginia. The federal government is closed, which means I can work on VOA Radiogram at home rather than at the office.

On VOA Radiogram during the weekend of 15-16 February 2014 (program 46), we will try another simultaneous transmission of text and an image. This time it will be text in MFSK32 centered on 2000 Hz, and the image in MFSK64 centered on 1000 Hz.

Here is the procedure:

1) Have two instances of Fldigi running.

2) Turn on the RxID (green) on both instances of Fldigi.

3) After the mode changes to MFSK64, turn off the RxID on your
second instance of Fldigi.

4) Enjoy

After program 46, we will take a break from simultaneous text and image transmissions. It's a lot of extra work for me to produce, and a lot of extra work for you to decode.

Program 46 will also include Chinese characters, transmitted as MFSK32 and later (and faster) as MFSK64L. I would grateful of recordings of the digital transmission of the Chinese characters, especially in the presence of interference or local noise.

Here is the lineup for VOA Radiogram, program 46, 15-16 February 2014:

 1:35  MFSK32: Program preview
 3:50  MFSK32/64: Press freedom index with simultaneous image*
10:49  MFSK32: Bing accused of censorship, with image
16:41  MFSK32: Hacking at Sochi Olympics, with image
22:09  MFSK32: Sample of VOA Chinese text**, with image
25:22  MFSK64L: Same sample of VOA Chinese text
27:28  MFSK32: Closing announcements

*Run two instances of Fldigi, starting with RxID on in both
instances. Test will be centered on 2000 Hz, the image on 1000
Hz.

**Use UTF-8 character set. In Fldigi: Configure > Colors & Fonts
> Rx/TX > Set top (white) box to UTF-8.

Please send reception reports to radiogram@voanews.com

From your reports, it appears that last weekend's simultaneous text and image transmissions were largely successful. Thanks for those reports, which I'll be answering in the next couple of days.


Kim

Kim Andrew Elliott
Producer and Presenter
VOA Radiogram
voaradiogram.net

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.

Kim

voaradiogram.net

Monday, February 10, 2014

XSV is not Dead!

Martin Foltz writes about hearing XSV (Tianjin Radio, China) in Southern California. 
Finally caught XSV this past week so they're still on.

8417.5 kHz XSV Tianjin Radio 2/4 1417UTC and 2/6 1345UTC with channel marker & "XSV" in Morse code, weak signal. 

Friday, February 07, 2014

VOA Radiogram for February 8-9

Last week was interesting.  The image centered on 2700 Hz in the second pass had far more interference than the first one, which was very clean.  I don't know if this is due to intermod, harmonic distortion, the effect of the higher frequency, or just the luck of the propagation draw.

We'll see again this week.  This should be illuminating.


From Kim Andrew Elliott:

Hello friends,

Last weekend's experiment with the simultaneous transmission of MFSK32 text and images was mostly successful. We'll try it again this weekend on VOA Radiogram.

The procedure will be the same. You can decode the two streams sequentially from your recording. Or you can run two instances of Fldigi, as follows:

1) In both instances of Fldigi, turn the RxID on (green).

2) An RSID for MFSK32 at 2100 Hz will be transmitted, moving both instances of Fldigi to an audio frequency near 2100 Hz.

3) On the second instance of Fldigi, turn the RxID off.

4) An RSID for MFSK32 at 1500 Hz will be transmitted, moving your first instance of Fldigi back to an audio frequency near 1500 Hz.

5) Test will be transmitted centered on 1500 Hz, and the images centered on 2100 Hz.

6) After the dual MFSK32 transmissions, you can turn off or minimize your second instance of Fldigi.

Here is the lineup for VOA Radiogram, program 45, 8-9 February 2014:

 1:30  MFSK32: Program preview
 4:06  MFSK32: Winter SWL Fest, with simultaneous image
 5:30  MFSK32: Graphene, with simultaneous image
10:05  MFSK32: Telescope
16:22  MFSK64: Image of telescope
18:24  MFSK64: St. Louis aviation, followed by image
23:52  MFSK64: Turkey Internet crackdown, followed by image
27:06  MFSK32: Closing announcements

Please send reception reports to radiogram@voanewss.com

The Mighty KBC will transmit a minute of MFSK32 again this weekend, via Germany, Saturday at about 1230 UTC on 6095 kHz, and Sunday at about 0130 UTC on 7375 kHz (8:30 pm EST -- part of a broadcast from 7 to 9 pm EST). Eric enjoys receiving reception reports, so please send them to themightykbc@gmail.com. Website is kbcradio.eu.

The Winter SWL Fest will be March 14-15 in suburban Philadelphia. I plan to be there to demonstrate the decoding of text and images from VOA Radiogram. More information at swlfest.com. Register in advance or walk in.

I'll now turn my attention to answering your reports from last weekend.

Kim

Kim Andrew Elliott
Producer and Presenter
VOA Radiogram
voaradiogram.net

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

*If you are in eastern North America and in the skip zone for 17860 and 15670 kHz, try this SDR receiver in the Netherlands: http://websdr.ewi.utwente.nl:8901/ .  This receiver is also good for hearing The Mighty KBC on 6095 kHz.