DJ5CW (ex DJ1YFK) - Ham Stuff

ETM-DIGI-1 interface - Manual and documentation
Morse code distance - Compare likeness of callsigns
TS-440S/AT repair notes - Under construction
DX-Cluster ⇆ Websocket Gateway - A small Go program that provide this
RBN activity charts - Generate activity charts for a callsign from RBN data
Band occupancy (30m) - Getting an overview of CW activity from the RBN
RBN bandmap - A pretty way to present reverse beacon spots.
Mind the gap! - Why spaces are important in Morse Code
Practice for the FCC exam - A little Perl script to be used with the current question pools
RBN Telnet Feed Filter - Reduces the mess on the bandmap!
IRC <-> Win-Test Chat bridge - Good for boring night shifts in the contest!
Experimental JavaScript Morse Decoder - Shows the limitations of browser based fun...
Idea: Morse Code Alarm Clock - For people that have trouble to get up in the morning!
Code snippet: Generating SSTV Martin 1 signals
PHP code snippet: Distance and bearing calculation for Maidenhead QTH locators
Morse code palindromes - Out of curiosity...
Morse-Barcode - A small PHP script to generate morse encoded barcodes
Narrow CW filters, do they help? - listening examples, some theory...
Morse My IP - Truly ridiculous
Beverage antenna switch - With push buttons for antenna selection.
QRQ head copy - How does it work?
db.pl - A small Perl script to do some power calculations.
Stereo CW - Dots on one, Dashes on the other ear. Does it work?
gnuplot - Using GNUplot for some quick contest statistics.
QSL return rates - for the QSL bureau and LOTW
QSL.tex - A QSL backside design in LaTeX

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@fkurz.net

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.

DJ5CW's Ham Radio Stuff

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RBN Telnet Feed Filter