DJ1YFK's Ham Radio Stuff


All kinds of things too precious not to share, in short articles. Constantly under construction or destruction. Note that code snippets are usually working minimum examples (often stripped of extra features). If you plan to use and of the code for anything serious, you may want to contact me. It's likely that I can provide you with some updates and good (?) advice.

Fabian KurzHam RadioStuff

RBN Telnet Feed Filter

The Reverse Beacon Network (RBN) aggregates CW Skimmer spots, both to be displayed on their website and as a telnet feed. The latter can be used e.g. in contests to populate the bandmap with new stations.

In some contests it may be desirable to filter out certain spots. DX Spider (which runs on the RBN telnet server) offers some filtering options, but it gets very tedious or impossible to set up filters for a large number of individual callsigns, such as members of a club.

I found myself confronted with this problem before the FOC Marathon 2011, where a) only QSOs with FOC members count for points and b) only a slow and limited internet connection was available to access the spotting networks.

The solution came in form of a small Perl script, which connects to the RBN telnet feed and then acts as a telnet server itself, offering a filtered feed to the connected parties.

Since the Perl script (and some further modifications and improvements of it) didn't show satisfactory results under heavy load (memory leaks etc.), it was re-implemented in a different way, with xinetd and a small C program to serve the spots, and a small Perl program to get the spots from the cluster. It is a hack, but it works very well.

Since this may be useful for many different purposes (for clubs, particular contests, or to filter for certain DXpeditions, etc.), the program code is available here, for anyone to use and download. There are no restrictions whatsoever on its usage, feel free to copy, modify, redistribute, sell or smoke it.


Old Perl version (not recommended!): rbnfilter.txt (4kb)

See also: RBN bandmap view - Websocket ⇆ Telnet bridge

Added: 23-Feb-2011. Last modified: 22-Dec-2012.

Fabian KurzHam RadioStuff