ALL
I have tested RBN / skimmer raw data and Excel with preprocessing with CSVed to
confirm station performance after many major CW contests I have been in.
In order to see how a station covers a certain target area, I typically take
one hour timeslots, one country or in the case us US, one zone to select the
RBN listeners and then calculate the averages and variance of RBN measurements.
Typically you I try to find some 50-100 measurements / TX station / hour for
comparisons. In The outcome is averages varying between 10 to 30 dB and a
variance of about 10 dB which is really quite a big number. This variance
contains all the differences between RBN listerner station antennas,
propagation, QSB etc., however the general grouping of stations to "high
performance" (OH8X, OH2BH, OH4A), "good" and "normal" holds quite well if you
know what antennas stations have at this end. A high stack is a high stack,
always.
Although it has been tempting to do, to me it seems to be statistically
impossible to confirm much smaller than 3-5 dB difference between stations
using this method. This is if you know the variance, number of measurements
and the difference between averages of measurements and perform a student's
p-test to confirm if the averages are really different or not. The rough
groupings hold really well though, difference between normal and high
performance stations holds. And I can see where my own signal sits in these
groupings.
MarkkuWW1C/OG2A/OH2RA
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