Thank you for another great response to the VOA Radiogram for
the weekend of 8 and 9 June. Your audio samples were especially
helpful.
During the past weekend, we experimented with mixing music
with MFSK text modes. Reducing the MFSK modes by 9 dB was not a problem if the
signal level was good, but the MFSK text did break up for some listeners if
reception conditions were marginal.
For many listeners, a new web page popped up after the VOA
News story in Flmsg format was transmitted. As for the EasyPal image, there was
more success in Europe than in North America.
This weekend, 15 and 16 June, we will mix some actual noise
taken from shortwave with MFSK text. After the noise begins, a VOA News story in
MFSK16 will first be transmitted at full level, then reduced to -6 dB, then
reduced to -12 dB. I will probably lose many of you when the level is reduced to
-12 dB, but please stay tuned: the audio level will soon be restored.
Please note that noise that is mixed with MFSK text as part
of the VOA Radiogram production is not an ideal simulation of co-channel
interference. This is because real co-channel interference involves two (or
more) transmitters at different locations and with different propagational
characteristics.
Here is the lineup for VOA Radiogram, 15 and 16 June
2013:
2:10 MFSK16: Program preview
1:58 MFSK16: Introduction to noise
experiment
10:09 MFSK16: At -0 -6 -12 dB versus noise
:59 MFSK16: Image of VOA logo
:47 MFSK16: Introduction to MFSK32
:51 MFSK32: Image of VOA logo
3:19 MFSK32: VOA News re Curiosity Rover on
Mars
MFSK32: VOA Radiogram logo
2:40 EasyPal Image of the week
1:10 MFSK16: Closing announcements
:20 Surprise mode of the week
As usual, your audio samples of bad reception that
nevertheless results in a successful decode of at least MFSK16 would be
appreciated. This email address -- radiogram@voanews.com -- seems tolerant of
attachments up to 20 MB or so.
Also, if you are able to use portable shortwave radios to
receive VOA Radiogram, this would be helpful. This will help us determine if
typical listeners will be able to decode the digital text modes.
Please send reception reports to
radiogram@voanews.com
Kim
Kim Andrew Elliott
Producer and Presenter
VOA Radiogram
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.
VOA Radiogram
radiogram@voanews.com
Twitter: @voaradiogram
