HF Beacons and the Reverse Beacon Network, 2017

Below is  a table of the twenty fixed-frequency stations most often posted by the RBN in 2017.

Position	Station	Frequency (kHz)	Number of Posts
1	W0ERE/B	10129	57,379
2	AA1K	1821	55,549
3	HB4FV/B	10134	53,240
4	4U1UN	14100	52,603
5	W6WX	14100	50,622
6	I1MMR	7026	50,212
7	N4BP	14022	43,144
8	EW7LO	7008	42,805
9	4X6TU	14100	41,937
10	4X6TU	18110	38,256
11	IT9SSI	14030	32,998
12	YV5DRN	7011	31,958
13	EA9HU	14016	30,811
14	4X6TU	21150	29,781
15	OK0EV	1854	29,459
16	RR9O	14100	29,328
17	DJ6UX	7039	29,114
18	YV5B	14100	27,900
19	CS3B	14100	26,682
20	KH6RS	14100	26,590

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. FCC regulations also appear to disallow the use of the "/B" indicator as used by station number 1, as the B series is allocated to China.
4. 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.