[A-DX] digi-dx-test 6070z (war gewesen)

Sa Mär 5 21:34:17 CET 2016


"Extra broadcast at 1930 on 6070Khz tonight. This is mostly in Olivia 
64-2000 to test decoding against Vatican Radio. However we 1 minute of 
MFSK32 at the start and 1 min 30 seconds of MFSK-128 also. MFSK128 is a 
Base64 version of a Midi audio file. Paste the text decoded into 
http://www.freeformatter.com/base64-encoder.html and press decode. It 
should download a file that can be renamed as a .mid file and opened in 
an audio player."

Ich habe das zwar "verpasst", wäre aber [hier} sowieso nix geworden, um 
diese Uhrzeit, einmal realistisch betrachtet.
Die Idee an sich ist zwar nicht schlecht, eine kleine digitale *.mid   
als b64-encodeten Text zu senden, aber in  MFSK128....... ??
Das setzt höchste Ansprüche an die Empfangsqualität voraus.  Schon ein  
einziger falscher Buchstabe im b64-Text und die nachfolgende Umwandlung
von *.b64 in ==> *.mid  ist  futsch.....
Die VoA hat das beim radiogram schon lange ad acta gelegt, maximal 
MFSK64 wären realistisch.

(ungefähr Textmitte)

".The following is my International Broadcasting column for the
March 2015 Journal of the North American Shortwave Association
(NASWA) ...
VOA Radiogram: Two years of strange noises on shortwave
Kim Andrew Elliott
...In addition to the decision about the mode was the question of
the speed of the mode. As a general rule, the faster the mode,
the less able it is to cope with difficult shortwave conditions.
MFSK16 (as in 16 baud) is amazingly robust in dreadful
conditions, but slow at 55 words per minute. MFSK64 is 240 wpm
but works well only in favorable conditions. MFSK128, at 480 wpm,
is blisteringly fast but really best suited for local VHF and
UHF. Ultimately, MFSK32 demonstrated the best combination of
speed (120 wpm) and performance in typical, i.e. usually not
brilliant, shortwave conditions."

Also MFSK128  besser für VHF+UHF......