Friday, March 16, 2018

Shortwave Radiogram weekend schedules

Two examples of an improved MFSK32 image transmitted at half-speed then decoded at full speed. Image transmitted at full speed are on left, at half speed on right. All are from the 1600-1630 UTC broadcast Saturday, 10 March, on 9400 kHz from Bulgaria. Top from @radio_no_koe in Japan, using an SDR in India. Bottom is from Merkouris in Greece (too close to the Bulgaria transmitter).


Hello friends,

For the summer, Shortwave Radiogram remains at the same UTC times. In North America, where daylight time is observed, the broadcasts are one hour ahead by local time, e.g. Sunday 4:30 and 7:30 pm and Monday 4:00 am EDT. (Summer time begins 25 March in Europe.)

Last week's experiment with MFSK32 images transmitted at half speed, designed by Mark Braunstein WA4KFZ, produced  interesting results. There were several examples of the half-speed images, decoded at full speed, providing higher quality images, as predicted. (See, hear, and decode one example.) In some cases, usually when the full speed image was good to begin with, any differences were not detectable.

The results could be biased by the signal improving or deteriorating from the time of the full-speed transmission to that of the half-speed transmission. We can correct for that (and probably will in a future broadcast) by transmitting both at the same time but at different center frequencies.

This weekend we will try something similar: text and an image transmitted concurrently but at different center audio frequencies. The text will be broadcast at the usual 1500 Hz. The image will be transmitted centered on 2200 Hz.

(The text transmission is on your spectrum from about 1250 to 1750 Hz. On the waterfall, sometimes you will see the second harmonic of the text transmission, which is from 2500 to 3500 Hz. The frequency of 2200 Hz is used for the image because its trace from 1950 to 2450 Hz completely escapes any interference from that second harmonic.)

You can decode the text and image simultaneously by running two instances of Fldigi. Or record the broadcast and decode the image later.

There will be no RSID transmitted at the beginning of the image on 2200 Hz. However, there will be a 15-second tuning signal to help you set Fldigi to the correct center frequency. The tuning signal begins at 12 minutes, 44 seconds into the broadcast.

Because transmitting both text and an image increases the amplitude of the audio, I reduce it during the dual transmission to reduce the chance of breaking a transmitter. If your text decode is not as good during the dual transmission, please let me know.

The image will also be transmitted as usual on the usual 1500 Hz center frequency after the text of the news item about (appropriately enough) noise pollution.

Here is the lineup for Shortwave Radiogram, program 39, 17-18 March 2018, all in MFSK32:

 1:32  Program preview
 3:26  Urban mining to reuse materials*
12:14  Polluting the world with noise**
20:39  Chinese lunar satellites will include amateur radio*
27:04  Closing announcements

* with image

** with the image at 2200 Hz and again after the text at 1500 Hz
Please send reception reports to radiogram@verizon.net
And visit http://swradiogram.net
Twitter: @SWRadiogram

Shortwave Radiogram Program 39
(17-18 March  2018)
Saturday
1600-1630 UTC
9400 kHz
MFSK32
Space Line, Bulgaria
Sunday
2030-2100 UTC
7780 kHz
WRMI Florida
Sunday
2330-2400 UTC
7780 kHz
WRMI Florida
Monday
0800-0830 UTC
7730 kHz
5850 kHz
WRMI Florida

 The Mighty KBC transmits to Europe Saturdays at 1500-1600 UTC on 9400 kHz (via Bulgaria), with the minute of MFSK at about 1530 UTC (if you are outside of Europe, listen via websdr.ewi.utwente.nl:8901/ ).  And to North America Sundays at 0000-0200 UTC (Saturday 7-9 pm EST) on 6150 kHz, via Germany. The minute of MFSK is at about 0130 UTC.  Reports to Eric: themightykbc@gmail.com . See also http://www.kbcradio.eu/ and https://www.facebook.com/TheMightyKbc/. 

 Italian Broadcasting Corporation (IBC)  For the complete IBC transmission schedule visit  http://ibcradio.webs.com/  Five minutes of MFSK32 is at the end of the 30-minute English-language “Shortwave Panorama,” per the schedule below:

Wednesday
2025-2030 UTC
5845 kHz
Europe, Middle East, Asia
Tuesday
0125-0130 UTC
5950, 11580 kHz
Americas
Friday
0225-0230 UTC
9955 kHz
Americas
Friday
0255-0300 UTC
5985 kHz
Americas
Saturday
0155-0200 UTC
5850, 5950, 9395, 9455 kHz
Americas
Sunday
0055-0100 UTC
7730 kHz
Americas
Sunday
1155-1200 UTC
6070 kHz
Europe

 Thanks for your reception reports! 
Kim

Kim Andrew Elliott, KD9XB
Producer and Presenter
Shortwave Radiogram
Reporting on international broadcasting at https://twitter.com/kaedotcom


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