Sunday, September 5, 2010

QRSS Averaging - Redundancy

With the help of Alessandro IW3SGT, I was able to collect some interesting data. Alessandro set his transmission so that his ident is sent out twice in a 10min period. Timing was perfect!
Towards the end of the session, strong fading dominated the game, and this is what this entry is about.

The last 30min of the opening look exactly like this

1800z - 1810z
1810z - 1820z
1820z - 1830z

The above spectra never show "SGT" completed. Have a look at the average of those spectra:

Here we go, thanks to the ident being TXed twice in the course of 10min, it is easy to figure out the ident from the averaged spectra.

BTW, adding the frame from just before the above mentioned 30min, result is really obvious...

1750z - 1800z
40m average
I am not sure, I remember to have observed a QSB frequency having a period of about 10min, that was on 600m, trying to decode G3ZJO's WSPR. Maybe a 10min averaging is not such a good idea after all, and 5min should be chosen.