Re: LF: MF: WSPR-15 this night

[Markus Vester <markusvester@aol.com>]

Hi Tobias,

 

thanks for the picture! The weak signal 5 Hz below DL6II might actually have been mine. I had sent only two WSPR-15 sequences on 475805 Hz (5 Hz below DL6II), starting 22:00 and 22:15. I was using the comparator output from the AD9850 (~ 20 mW), barefoot to the coil and antenna at half height (0.5% efficiency), thus about 0.2 mW ERP. On the other hand, DJ6LB (who is located about 20 km from me) was on 475812 Hz throughout the night, about 2 to 4 Hz above DL6II.

 

Though in this case the weak transmissions were not decoded, I think that WSPR(-15) in general seems to cope rather well with severe QSB (maybe better than QRSS). However a "bent" signal with variable drift (like that from Vinny's transverter) may actually be less likely to decode than one with the first part missing. The situation may be analogous to a phase inversion near the middle of a PSK sequence, resulting in half of the symbols being systematically wrong (50% error rate). On the other hand, replacing half of the sequence by random noise produces only 25% errors.

 

Best 73,
Markus (DF6NM)

-----Ursprüngliche Mitteilung-----
Von: Tobias DG3LV <DG3LV@gmx.net>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: Mi, 3 Feb 2016 8:52 am
Betreff: Re: Re: LF: MF: WSPR-15 this night

 

Hi Vinny, MF ! 

Good job ! Your signal was ok and loud last night. Congrats ! 

 

There could have been an additional WSPR-15 station on 475.807 at 22:00h  

to 22:30h, but it was too weak to be decoded at my side.(see picture) No  

one else was listed for a decode, so who was it ? 

 

Anyone on this reflector ? 



73 de dg3lv Tobias

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