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Re: [wsjt-devel] FT8 decoding sensitivity: WSJT-X vs. JTDX
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From: DG2YCB, U. <DG...@gm...> - 2019-05-03 15:21:24
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Next curious observation: WSJT-X 64 bit and JTDX in parallel, listening to 6m band, both connected to the same audio source, no QSO running, only a few stations on band, with both programs saving all audio files to my SSD. Results: From time to time JTDX decodes more callsigns. So far so good (or bad)… But now comes the interesting thing: Of course I liked to reproduce decoding and opened the recorded audio files in both programs. The file JTDX had recorded lead to 2 decodes in JTDX and 1 decode in WSJT-X (as expected). Surprisingly, the file WSJT-X had recorded lead to only 1 decode in both programs. Really strange… How can that be? I opened both files with Audacity and made a rough analysis. Spectrum is identical, but JTDX’s file obviously was sampled for the full 15 seconds interval while WSJT-X’s file showed zero line for the last milliseconds. Might that have something to do with it? Perhaps a timing issue? May have WSJT-X missed the final bits of DL2AYK’s transmission because sampling stopped – for what reason ever - too early? Or is this another case of “audio dropouts”? Find all files of this case in dropbox: <https://www.dropbox.com/s/btv80vehuqmlvmd/6m_WSJTx_vs_JTDX.jpg?dl=0> https://www.dropbox.com/s/btv80vehuqmlvmd/6m_WSJTx_vs_JTDX.jpg?dl=0 https://www.dropbox.com/s/hxotwlwc3xr78sv/190503_125900_JTDX.wav?dl=0 https://www.dropbox.com/s/agk3i9p2wg4la68/190503_125900_WSJT-X.wav?dl=0 https://www.dropbox.com/s/78qj01b1nzwv21j/6m_WSJTx_vs_JTDX_Audacity.jpg?dl=0 73 de Uwe, DG2YCB |
