Thursday, April 03, 2014

Set and Forget VOA Radiogram for April 5-6

From Kim Andrew Elliott:

Hello friends,

Last weekend's "battle of the 100-word-per-minute modes" produced useful results. Based on a quick analysis of the percentage of correct characters, the average of all responses is…

MFSK32                98%
MT63-1000L        90%
Thor25x4             86%
PSKR125               74%

[My results were very close to these percentages. Around 100% for MFSK32, 99-100% for MT63, mediocre copy on the Thor, and rough copy on the PSKR125. PSK modes don't seem to fare well in this particular application. -Hugh]
 
The MT63-1000L would have had an even better result if it had not been for four occasions of no decode at all. In situations where any MT63-1000L text was received, its performance was very close to that of MFSK32.

MFSK32 does have the advantage of being about 20 words per minute faster than MT63-1000L. Furthermore, MFSK32, unlike MT63-1000L, can be used for images.

This weekend, VOA Radiogram will return to an all-MFSK32 "set it and forget it" format. I do this at the risk of losing the interest of those of you who prefer a program replete with experiments. The program will be interesting in that it will include four images and an Flmsg CSV form with the updated VOA English transmission schedule.   

Here is the lineup for VOA Radiogram, program 53, 5-6 March 2014:

All MFSK32 centered on 1500 Hz...

1:36  Program preview
2:40  Head of Russian social network resigns, with image
9:28  NASA aircraft research, with image
16:13  Maryland company helps in search for MH370, with image
23:04  VOA English broadcast schedule as Flmsg* CSV form
26:44  Closing announcements

*To make Flmsg work with Fldigi (both can be downloaded from w1hkj.com), in Fldigi: Configure > Misc > NBEMS -- Under Reception of flmsg files, check both boxes, and under that indicate where your Flmsg.exe file is located.

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.

Reception of the Sunday 0230 UTC broadcast in Europe: This broadcast is audible in Europe but occurs at a rather inconvenient time for Europeans. If you are in Europe, please consider unattended reception of this transmission. Three ways to do this involve leaving you radio on and tuned to 5745 kHz all night: 1) Use the Audacity audio recording software, specifically its Transport > Timer Record feature. 2) Use Fldigi's File > Text Capture feature, then retrieve the decoded text from the file that will contain mostly gibberish. 3) Instead of using Fldigi text capture, scroll up through the receive pane to find the decoded text, which you can copy and paste to a text editor or word processor.

The Mighty KBC will again transmit a minute of MFSK64 Saturday at about 1230 UTC on 6095 kHz, and Sunday at about 0130 UTC (Saturday 9:30 pm EDT) on 7375 kHz. Both frequencies are via Germany. STF Radio International is also planning tests on The Mighty KBC, presumably again in MFSK32 about 15 minutes after my MFSK64 transmissions.

Amateur radio digital nets: As KD9XB, I usually check in to the New York NBEMS net Saturdays at 1400 UTC (10 am EDT) on 7036 kHz and the Pennsylvania NBEMS net Sundays at 1500 UTC (11 am EDT) on 7072.5 kHz. I occasionally also check in to the USeast NBEMS net Wednesdays at 2300 UTC (7 pm EDT) on 7036 kHz. All these nets are USB and start with Olivia 8-500, then change to another mode such as MFSK32 or MT63-1000L for messages.

Thanks for your reception reports last weekend, and I look forward to hearing from this weekend.

Kim

Kim Andrew Elliott
Producer and Presenter
VOA Radiogram
radiogram@voanews.com
Twitter: @voaradiogram