[hpsdr] Waterfall Displays

[Jeremy McDermond]

On Feb 19, 2010, at 1:15 PM, Mike G wrote:

> ***** High Performance Software Defined Radio Discussion List *****
> 
> Hi,
> 
> I have seen the pictures of the waterfall displays. Not being a sonar guy for the submarines, they do not mean much to me. Which books or other resources would you recommend for me to use to get familiar with the information and interpretation of the waterfall displays?

I'm not sure I have any books or anything about waterfall displays, but the concept is pretty simple.  It's essentially the same thing as your panadapter but looking at three dimensions:  Frequency, Signal Strength, and Time.  Like the panadapter, the frequency is plotted on the X axis.  Time is on the Y axis, that's why it moves down at regular intervals.  The third paramter, Signal Strength, is mapped to the color of the pixel.  The more intense the color of the pixel, the larger the signal strength.

I mainly use mine to spot signals.  Once you've looked at it for a while, you learn to see what an SSB signal looks like (I'm not really a CW guy).  Most things are going to be vertical lines of some sort.  You'll see AM signals as a single bright carrier signal at the carrier frequency with a symmetrical pattern around it for both sidebands.  CW signals will look like paper tape traces of the CW signal.  I find it's one of the more useful graphical displays because after a few seconds of the waterfall, I can see exactly where the signals on the band are.  And remember at 192kHz sample rate, you're can see all of the phone portion of 40m, and nearly the entire phone portion of 20m at the same time.

Hope this helps.  I just spent a few hours trying to implement one, with some small amount of success.

> Thanks
> 
> Mike G.
> 
> WA5FJV

--
Jeremy McDermond (NH6Z)
Xenotropic Systems
mcdermj at xenotropic.com




 1266605404.0