In this post I take the first step, and determine which stations make reasonable candidates for further investigation.
The RBN can quickly tell us which beacons are posted most frequently, simply by counting posts of stations that transmit on a single frequency over a long period. If we look at the period from the RBN's inception in 2009 to the end of 2016 (using, for example, this file), we find the following "top twenty" beacons:
|Position||Station||Frequency (kHz)||Number of Posts||Earliest Post||Latest Post|
- Frequencies are rounded to the nearest kHz;
- The first two positions are occupied by what is really the same station, which appears to transmit on 7026.5 kHz;
- Positions 9 and 10 appear to be occupied by a single station, using alternative versions of a single callsign;
- 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;
- FCC regulations also appear to disallow the use of the "/B" indicator as used by station number 9, as the B series is allocated to China.
- 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);
- Of the twenty stations in the list, all but five were still active as of the end of 2016.