Re: LF: WSPR-8 Test

[g3zjo <g3zjo@psk31.plus.com>]

Well done Markus

I wondered how you were going to do the de-code, the TX bit is easy isn't it..

I am surprised you didn't get timing errors on the replay. Here I find cumulative errors with normal 2 min WSPR and MP3 recordings, so much so I abandoned the idea, despite successes reported by some Italian stations for use in a beacon.
This method tried was to use several 2min WSPR recordings with pauses between them played as a loop, different record / playback devices introduce different timing errors. Do you remember wanting minimum Wow and Flutter on your music recordings, the new music download generation doesn't care. :-)

73

Eddie G3ZJO


On 21/09/2012 01:07, Markus Vester wrote:

First decodes using 8-minute WSPR:

 

2012-09-21 00:00	DK7FC	0.137508	+7	0	JN49ik	1	DF6NM	JN59nj	175	91
2012-09-20 23:52	DK7FC	0.137508	+3	0	JN49ik	1	DF6NM	JN59nj	175	91

 

Between 23:36 and 23:43:20, Stefan was transmitting 8-times slow WSPR with low power on 136172 Hz. This was recorded here to an IQ file using SndInput from DL4YHF, and replayed 8x fast during the next 2-minute, slot starting 23:44. In the process the audio was frequency shifted from 670 to 2000 Hz, and added to the normal audio data for WSPR.  Thus with the 4x acceleration, Stefan's transmission appeared 8 instead of 2 Hz above center.

 

This is all still a bit improvised, but the concept seems to work.

 

Best 73,

Markus (DF6NM)

 

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Version: 2012.0.2221 / Virus Database: 2441/5282 - Release Date: 09/20/12