HF Beacons and the Reverse Beacon Network, 2019

Below is  a table of the twenty fixed-frequency stations most often posted by the RBN in 2019.

Position	Station	Frequency (kHz)	Number of Posts
1	YU7QF	14017	108,006
2	W6WX	14100	68,976
3	I1MMR	7026	68,942
4	YV5B	14100	67,984
5	AA1K	1821	67,707
6	CS3B	14100	67,537
7	4U1UN	14100	66,934
8	EW7LO	7008	66,578
9	HA8RM	7009	47,940
10	DO1EK	3541	46,295
11	DK4AN	3569	44,395
12	DL2IAD	7024	39,752
13	UA3KW	14007	39,633
14	DK5JPL	3541	39,062
15	4X6TU	14100	37,580
16	SQ6JAN	3565	36,354
17	OH2B	14100	35,678
18	F4DIA	7010	34,904
19	HA8RM	3509	34,328
20	N4BP	14022	34,041

Notes:

1. Frequencies are rounded to the nearest kHz;
2. I am unsure how the U.S. stations in the list can be legal, since the FCC's regulations appear to limit [unattended] HF beacons to a portion of 10m.
3. It is my memory that the original HF beacons were all located on 28 MHz, so that listeners could be made aware of an opening. It is noticeable that not a single one of the stations on the list above is on 10m: the vast majority are on bands that can reasonably be expected to support some kind of non-local propagation at almost all times (which is probably the very reason that they are posted by the RBN so often -- but one does wonder what the putative purpose of such a beacon is);

Below are figures showing, for each of the stations in the table above, the signal strength as reported by the ten RBN stations that most frequently posted each individual beacon station.

In the following figures:

1. The ordinate for each of the strip charts ranges between 0 dB and the value shown as FSD (i.e., full scale deflection) near the bottom right-hand corner; in this case, the maximum value of each strip is therefore 80 dB.
2. The value plotted in this manner is the value denoted SNR by the RBN.  Remember that the RBN has an odd definition of SNR.
3. The abscissa is divided into a number of bins of equal duration. On each plot there are 100 such bins; because the duration covered by each plot is one year, each bin therefore covers about 3½ days.
4. At the bottom of each strip chart is a coloured bar. Each bin in these bars is coloured so as to represent the total number of times that the RBN station spotted the beacon in the period covered by the bin.The colour legend for each figure is to the right of the figure.
5. For the period covered by each 3½-day bin, the lower quartile of SNR readings is coloured grey, the upper quartile is coloured white, and the middle two quartiles are coloured blue.
6. The vertical order of the various RBN stations is determined solely by the chronological order in which each station first spotted the beacon.