LF: Colour-coded azimuth spectrogram

[DL4YHF@aol.com]

Hello Group,

The colour-azimuth spectrogram 'invented' by Markus DF6NM is now available in the latest version of Spectrum Lab (V2.2 b3 or later). What's that ? Visitors of the Ham Radio this year will remember: The colour azimuth spectrogram basically shows the intensity of a signal as the intensity of a colour, and the angle-of-arrival as the colour hue value. The technical background and some applications can be seen in Markus' presentation which is available online:
http://members.aol.com/df6nm2/ColourDF/ColourDF.htm


The implementation of the colour direction finder in SpecLab now supports..
- two basic antenna configurations, the simpler one with 180° bearing ambiguity
- software cardioid to cancel noise from a certain direction (only for the spectrogram yet)
- calibration can be loaded from textfile (frequency response data with amplitude+phase)
- all possible frequency resolutions / waterfall scrolling speeds now work in RDF mode too
- azimuth readings for a couple of user-defineable frequencies can be written to a textfile

To use it on LF, you need a dual-channel receiver which converts the LF band down into the audio passband of a soundcard (below 22kHz). 
More info and a download link is at
www.qsl.net/dl4yhf/spectra1.html 

(follow the link to the latest release which is "V2.2 b3" at the moment).

I use this radio direction finder on VLF, it appears to be more sensitive for very weak signals than a classic spectrogram display.

Thanks to Markus DF6NM for the original project in QBasic and to everyone who helped testing the program. As always, suggestions are welcome. If you are interested in the sourcecode of the RDF module, it is available on request (written in C++).

Regards,
Wolf DL4YHF

P.S: Dave (YXM) - would you like to update the SpecLab version on your website ? If so, and you cannot download the recent version from my website, I can mail the archive to you from the office.