zaterdag 2 mei 2015

6 m WSPR analysis for Roger G3XBM

In his informative Blog, Roger G3XBM wrote about aircraft scattering of signals on 6 m.
I had the pleasure of making an analysis of the WSPR spots reported by Roger.

In WSPR the drift is measured over a period of 1 minute, so the drift is given in Hz per minute.
Recently I included Drift in my Excel spread sheet that I use to make an analysis.


  • The value in the table, such as  -4, is a spot with a drift of -4 Hz per minute.
    Positive drift means that the radio path is getting shorter and negative is longer.
  • The signals of M0MVB show spots with a drift of -2 and   3 Hz per minute.
    It is possible, that there is a flight paths involved in the spots with -2 and an other path with the spots of   3 Hz per minute.
  • The scattered signals with drift, sent by M0YOU are very strong, with a lowest possible power of 1 mW. The spot with no drift (0 Hz per minute) has a lowest possible power of 50 mW, thus is 17 dB weaker.
  • The signals of M0EMM show no drift. So it's possible that there is no airplane scatter here, but an other form of propagation, such as difraction. Notice that all these spots are made within one hour.
Thanks to Roger. FB.

A few day ago I wrote to Roger: See article
Hello Roger, 
This evening I took some time to make an analysis of a number of spots on 6 meter.
I took the most interesting spots for airplane scatter.
I hope you like it and can place it in your blog.
I left in M0EMM to show the difference. hi
Positive drift means the path is becoming shorter.

The spots of M0MVB shows spots where the path is becoming shorter (+3Hz per minute)
and spots where the path is becoming longer.   (-2 Hz per minute)
I just saw that the spots of M0YOU with scatter, are much stronger than the spot without scatter. 
The lower the lowest possible power, the stronger the signal.  
A lowest possible power of 1 mW is 17 dB stronger than 50 mW. hi.
I left in the spots of M0EMM, to show that there is no Doppler and the signals are not that strong.

Good luck in further analysis,
73, Bert PA1B

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