Operation Deep Freeze 2017/2018?

VK3RX

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#2
Update. Heard comms today on 261.925MHz, around 0330UTC.

Aircraft callsign missed, but heard voice "calling in the blind, looking for 0330 Christchurch weather".

Followed a short time later by a data transmission lasting about 20 seconds. These occurred every half hour, so I assume they were Christchurch weather reports in text.

Finally heard part of aircraft voice comms, but response not heard, which suggests Base Ops may have been operating direct and not via SATCOM?.

Aircraft may be using HF or CPDLC to talk to MAC CENTER.

At 0630UTC heard same type of data transmission on 263.725MHz, the frequency they have used in previous years for voice comms.

Anyone recognise the data mode and/or suggest a program that might be able to decode?
 

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VK3RX

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#4
It sounds like some form of fax or SSTV-type mode, because it sounds like it has a line sync pulse.

I downloaded and registered Multipsk but can't get it going with my Dell desktop's sound card(s). I wanted to use it to analyse a wave file but I can't get the program to do that with its supplied BPSK31 file :( Messed around for hours trying all sorts of input/output combinations, a loop between the two etc. but gave up in the end. Something to revisit on a rainy day. Fldigi works fine on the PC, but is limited in the modes it can decode.
 

SDRPlayer

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#5
Damien, i converted those files to .wav and ran them though Multipsk. Those pips are at the 2k mark on the spectrum and the only mode i can get it to trip on is sstv PD290, though this may mean nothing as the signal is pretty noisy. I have also run it though RX-SSTV PD290 with no image. Could try Audacity for a better idea.
 

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VK3RX

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#6
Well done - thanks for that.

As received here the signal wasn't noisy it was S9, so I guess the image is just undecoded data.

It was worth a try :)
 
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