Sunday, July 3, 2022

How the RBN Knows Where You Are


In the aftermath of the roll-out of the new RBN website, this is an attempt to set down, in one place, an explanation of how the RBN locates spotters and spotted stations on its map.  The RBN programmers have reviewed and confirmed this.  In the discussion below, Aggregator refers to the software by W3OA that is required to connect Skimmers to the RBN.

There are 3 use cases:  spotters, ordinary spotted stations, and beacons.

Spotters are located solely by the grid square information they provide on the Operator tab of Skimmer or Skimmer Server (or in the INI file of RTTY Skimsrv).

Ordinary spotted stations are located through a process:  The primary source is  You can check your QRZ data by going to your callsign’s listing, and then going to your call on the right end of the blue menu bar.  Name, address etc. may be provided either by your licensing authority (in the US case) or by you when establishing your QRZ presence.  However, if you go to the sub-menu entry “Edit [callsign]” you’ll see the item “Map, Grid Square, and coordinate settings.”  What is reflected there can readily be changed by a station operating portable – enter a new grid square, lat/long coordinates, or simply move the mapped location to where you are now (if you do the latter, don’t forget to change back when you return home).

If the QRZ lookup fails, we check the FCC database for US-licensed stations.  If that lookup fails, or the station is not in the US, we then go to a static location database and look for the station’s callsign prefix (  It will then return the geographic center of the call area (W0 for example) or the geographic center of the whole country itself.

The website caches such lookups for a period of time (less than a day) and then tries again the next time the station is spotted.

Beacons are a little tricky, because their transmissions typically do not meet CW or RTTY Skimmer definitions of a CQ transmission (number of repetitions of the callsign, and CQ or TEST key words) .  Aggregator usually forwards only CQ spots to the RBN (to avoid spotting every reply to every CQ, except on 6 meters and above, where the Aggregator will forward every spot it gets from Skimmer).  There is an option in Skimmer and Skimmer Server (on the Telnet tab) to uncheck the Post Only “CQ” Spots checkbox) to forward all spots, and we recommend that all node operators uncheck that box, so then the Aggregator will be able to forward beacon spots to the RBN as well.

NCDXF beacons are easy – we have a list, and forward them automatically.  Other beacons are forwarded in the same way *if* they are included in a list of beacons derived from three widely-accepted lists that are publicly available.  Aggregator automatically downloads the latest list.

So that’s the story.  Comments welcome!


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