[A-DX] VOA Radiogram, 30-31 May 2015, includes SSTV

[Roger]

Am 16.06.2015 um 14:02 schrieb VOA Radiogram:
> Hello Roger,
> Thank you for this report.
> Attached is the gallery.
> With your IF recordings, you might be able to help us determine if SSB is better than AM for decoding the modes, or if there is no difference.
> All the best,
> Kim


1.)   My current opinion on the subject:
        In 90% of all cases pure USB or LSB is the simplest and best 
solution.
        It may also be, that some modes do not like a combined sound, eg 
THOR. Separate decoding of the sidebands was the only way
http://www.rhci-online.net/radiogram/VoA_Radiogram_2015-06-20.htm#THOR-SSB


2.)  But there are special hardship cases, where you have to exhaust all 
possibilities.
       MFSK-64 also likes AM and DSB de-modulation, especially if its 
structure has a scattered component with frequency shift:
http://www.rhci-online.net/radiogram/VoA_Radiogram_2015-06-20.htm#DX-302



3.)  It is always better if you own IF recordings. So you can transform 
unknown sounds in text, days later.
       So I was able to identify a OLIVIA similar sound on 27635 kHz as ROS.
       But this chat mode for weak signals, which is also available on 
regular amateur radio frequencies, is not designed for continuous 
broadcasting transmissions.
http://www.rhci-online.net/radiogram/VoA_Radiogram_2015-06-20.htm#ROS



roger