martedì 20 maggio 2014

VOA Radiogram, program 60, 24-25 May 2014 & program 61, 31 May-June 1 2014


Il programma principale di decodifica usato è Fldigi  (w1hkj.com)  funziona per Linux, Free-BSD, OS X, Windows XP, NT, W2K, Vista e Win7., ricevitore in AM

Hello friends,

Thank you for your reception reports for VOA Radiogram during the past weekend (17-18 May, program 59).

I continue to be away from the office most of this month, so I will not be able to respond with the e-QSL until early June.

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. 

To decode the digital text and images transmitted on VOA Radiogram, download Fldigi, Flmsg and Flamp from w1hkj.com. See also how to decode the modes.

VOA Radiogram, program 60, 24-25 May 2014

This program will include two interesting stories about the Internet, but because of their length we will use the faster MFSK64 mode (240 words per minute). Apologies to those who do not receive 100% copy of the MFSK64 text because of challenging shortwave conditions. 


1:31  MFSK32: Program preview
 2:48  MFSK32: Tropical storms, with image
 6:54  MFSK32: Russian scientific cooperation, with image
14:10  MFSK64: China Internet censorship, with image
21:35  MFSK64: Comparing Internet censorship regimes
27:21  MFSK32: Closing announcements


Please send reception reports to radiogram@voanews.com

VOA Radiogram, program 61, 31 May-June 1 2014
(The "VOA Radiogram Picture Show")


To make time for all the material in this program, my usual voice
introduction will be missing. The program preview in MFSK32 will
start immediately after the opening music.



On program 61, instead of news stories from VOA News,
we will experiment with the transmission and decoding of
images.

In the first part of the program, we will experiment with
MFSK images. Later in the program, an EasyPal digital image will
be transmitted.



The Fldigi software allows for the transmission of MFSK images at
different speeds: X1, X2, and X4. X2 and X4 "paint" more quickly,
but result in lower resolution: X2 is fuzzier, and X4 is
fuzziest. (Fldigi software is required to decode the X2 and X4
images.)

As the symbol rate (baud) of the MFSK modes increases from MFSK32
to MFSK64 to MFSK128, the resolution of images sent in those
modes also increases. The time required to send a picture is the
same for MFSK32, MFSK64, and MFSK128.

We therefore have two variables: the transmission speed and the
symbol rate of the MFSK mode.

We will transmit the same VOA Radiogram test card (254x197 pixels) as follows:

MFSK32 X1
MFSK32 X2
MFSK32 X4

MFSK64 X1
MFSK64 X2
MFSK64 X4

MFSK128 X1
MFSK128 X2
MFSK128 X4

EasyPal.  Also on program 61, our experiments with the EasyPal digital
image mode resume after a break of several months. Download the
EasyPal software from vk4aes.com. For practice, radio amateurs


transmit EasyPal images on 14233 kHz.

EasyPal is the work of Erik, VK4AES, in Australia. His software
uses DRM (Digital Radio Mondiale) encoding to allow the sending
of image files over an HF or VHF using only 2.5Khz (same as
voice). EasyPal is also known as Digital SSTV (slow scan
television).

The EasyPal transmission will be the same test card transmitted
earlier in the program in the various MFSK modes. The EasyPal
transmission will be just over 7 minutes. The picture might
appear before the 7-minute transmission is completed, or it might
not appear at all -- there is a rather high failure rate with
EasyPal on shortwave.



(Mark in Virginia recommends looking at, and perhaps also taking a
screenshot of, the MSC and FAC sections of the EasyPal display
during reception. Look for the MSC button. "For the 4-quadrant
displays, the signal should stay well confined within the four
regions of the graph. Points that are widely scattered are
evidence of amplitude and phase distortions. In the ideal case,
there would be four 'tight' clusters of points in each quadrant.
Distortion effects cause these points to spread out, making
decoding more difficult.")


Please send reception reports to radiogram@voanews.com.




The Mighty KBC, transmitting from Germany, will continue its MFSK64 transmissions Saturdays at about 1130 UTC on 6095 kHz and Sundays at about 0130 UTC (Saturdays 9:30 pm EDT) on 9925 kHz.
Reports to  themightykbc@gmail.com.


Thanks for listening, decoding, and reporting, and for all your support.

Kim

Kim Andrew Elliott
Producer and Presenter
VOA Radiogram

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