I here show various plots of the G(15, 100) grid-based scatter metric, G(15, 100), for the Reverse Beacon Network (RBN), using data from the inception of the RBN up to the end of 2020.

As in the past I note that a reasonable *a priori*
case can be made on the basis of propagation characteristics that
somewhat different metrics in the G(Δ, n) series might be better
representations of RBN coverage on some of the bands. However, rather
than make this into a full-scale research project, I shall here simply continue to use
the G(15, 100) metric on the basis that it seems "good enough" on all
bands.

#### RBN Posting Stations as a Function of Time

We begin by
looking simply at how the number of per-band posters to the RBN has
varied since the RBN's inception. (NB Throughout this post, we ignore
posters for which the location is not recorded by the RBN; plots for which the abscissa is time show one datum per month.)

First, a plot of the total number of posters as a function of time:

This can be more compactly represented, along with similar per-band data for 160m through 10m (excluding 60m):

#### G(15, 100) as a Function of Time

Turning now to the geographical distribution of the posting stations, we
can display the mensal values of G(15, 100) in a similar manner:

These figures seem to make rather clearly the point that, while the total number of stations posting to the RBN has increased slightly over the past few years (although in an uncertain manner), the underlying geographical distribution has barely changed, and is essentially static at 30% of the world's surface. One assumes (although I haven't checked) that this is because all the "easy" land-based locations now have at least one spotting station, and any expansion of the network, if such is desired, will probably have to concentrate on island states.

#### G(15, 100) as a Function of the Number of Posters

Finally, we can combine the mensal values of G(15, 100) and the number of posters. Firstly, including all bands:

The summary plot for these data is slightly different, as the ordinate is multi-valued for some values of the abscissa. So, in this summary plot, we take the mean value of G(15, 100) in bins of width equivalent to ten posters, and plot rectangles in the equivalent colours:All in all, a picture emerges in which the RBN, after expanding and increasing coverage for the better part of a decade, became essentially static in early 2017 and is now more or less in statis.
## No comments:

## Post a Comment

Note: Only a member of this blog may post a comment.