[A-DX] voa-radiogram 1. und 2. Februar

[Herbert Meixner]

http://mt-shortwave.blogspot.co.at/2014/01/voa-radiogram-february-1-2.html

-----------------------------

Hello friends,

Last weekend's experiment with the two simultaneous MFSK16 streams on 
one broadcast channel worked well, for the most part, according to your 
reports. Perhaps a future software application will simplify the 
decoding of simultaneous digital signals.

This weekend, we will do another experiment with simultaneous streams. 
It will involve MFSK32 text transmitted on a center audio frequency of 
1500 Hz, and an accompanying MFSK32 image centered on 2100 Hz.

You can decode the two streams sequentially from your recording. Or you 
can run two instances of Fldigi, following this procedure:

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) A VOA News story will be transmitted, with the text at 1500 Hz, and 
the image at 2100 Hz. You will probably notice mixing products on the 
waterfall when both streams are transmitted simultaneously. Do these 
mixing products have an adverse effect of the decoding of the text or image?

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

Here is the lineup for VOA Radiogram, program 44, 1-2 February 2014:

  1:42  MFSK32: Program preview
  3:19  MFSK32: China moon rover with image
  6:56  MFSK32: Same story and image transmitted simultaneously
  9:51  MFSK32: Al Jazeera reporters in Egypt, with image
15:26  MFSK32: Washington Auto Show, with image
23:18  MFSK64L: Beehive Radio in Cambodia
26:22  MFSK32: Beehive Radio logo
28:08  MFSK32: Closing announcements

Please send reception reports to 

A few additional notes:

Turn off the AFC. Many VOA Radiogram listeners recommend turning off the 
AFC (lower right corner of Fldigi) for best decode, especially in 
unattended receiving situations.

The VOA Radiogram broadcast Saturday at 0930 UTC is not bringing many 
responses. Reception in Europe is probably deteriorating as we approach 
spring. On the other hand, reception all the way to the west cost of 
North America has been very good. The problem is that 0930 UTC is the 
middle of the night in North America. So I would suggest unattended 
reception for later retrieval.

One way to accomplish this is the Audacity audio recording/editing 
software. Audacity has a useful timed recording function: Transport > 
Timer Record.

Of course, you have to keep your receiver on all night, unless your 
receiver also has a timer.

You can also decode VOA Radiogram while you are asleep using the Fldigi 
File > Text Capture function. If you do not want a night's worth of 
mostly random characters taking space on your hard drive, you can also 
go to the receive pane of Fldigi, copy the text from VOA Radiogram, and 
paste it to a text editor. The MFSK images will be in the folder 
\fldigi.files\images.

This weekend's experiment with two simultaneous digital streams might 
not lend itself to unattended reception. You can run a second instance 
of Fldigi with the RxID off and the center frequency pre-set to 2100 Hz, 
but the audio frequency as received might not be exactly at 2100 Hz.

The Mighty KBC, kbcradio.eu, based in the Netherlands but using 
transmitters in Germany, will broadcast a minute of MFSK32 this weekend: 
Saturday at about 1230 UTC on 6095 kHz, and Sunday at about 0130 UTC on 
7375 kHz (Saturday evening 8:30 pm EST). The center audio frequency is 
the usual 1500 Hz. Reports to  .

I will try to answer your reception reports from last weekend before the 
end of this coming weekend. Your reports are very helpful and much 
appreciated.

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.

voaradiogram.net

Kim Andrew Elliott
Producer and Presenter
VOA Radiogram
at 11:56 AM Labels: VOA Radiogram