LF: Direction-sensitive waterfall display

[DL4YHF@aol.com]

Hello group,

An attempt to trigger some experimentation..

Is there any interest to use the direction-sensitive waterfall display (as first built by Markus DF6NM), or does anyone in the group use it at all (still, or already) ? 

If so, I am thinking about adding a few new functions for this in the next release of Spectrum Lab. The basic RDF-spectrogram (alias colour-azimuth spectrogram) has been implemented in SL since two years or so, but -apart from Markus and myself- no-one seems to use it on 136 kHz. My own LF activity is very low at the moment, due to lack of an LF antenna at the club station DF0WD.

On even lower frequencies (ELF and VLF), the colour azimuth spectrogram has proved to be capable of digging signals out of the noise which were invisible on a classic (ampitude-only) waterfall. 
On 136 kHz, with a crossed-loop antenna for LF and two-channel RX, the principle may have offer some improvement - if anyone has the time and a quiet location to build such a system. If you are quite new to this group and don't know what this is all about, look at

members.aol.com/df6nm2/ColourDF/ColourDF.htm

or

www.qsl.net/dl4yhf/speclab/colourdf.htm

New functions which may be added (if there is some interest in this at all):

- adding a second or even a third nulling cardioid, 
  to eliminate QRM from different directions
 (at the moment, there is only ONE nulling direction implemented in SpecLab)

- modified noiseblanker, so that both channels are treated the same way
 (at the moment, there are independent noiseblankers for both channels which 
  makes no sense for the radio-direction finder)

- and some other goodies which are too tough to explain with my bad english.

Best regards, 
Wolf DL4YHF