[Elecraft] [P3] Waterfall Display

[Bill W4ZV]

ke7vwi wrote:
> 
> Does anyone have a recommendation on an article or some info on  
> using/interpreting the waterfall display?
> 

I searched but the following is the best I could find (which isn't great):

http://en.wikipedia.org/wiki/Spectrogram

A waterfall is basically a spectrum (signal amplitude versus frequency) but
with the added dimension of time (amplitude versus frequency versus time). 
A waterfall is most useful for detecting signals that are not continuously
present.  For example a weak DX station only sending short bursts when he's
answering callers that may be calling split on a different frequency.  Or
for extremely weak signals fading in and out of noise (e.g. QSB on the low
bands or meteor scatter at VHF).  For weak signals buried in noise, your eye
would probably never detect these in a spectrum display but they become
quite apparent in a waterfall display.  Once you know exactly where a weak
signal is, then you can tune your receiver to the exact frequency and begin
to apply filtering in both the radio and your ear/brain to copy it.

I use waterfalls mainly for weak signal CW on the low bands.  They're
especially helpful for signals at or below the noise floor.  I understand
they also work well for digital (not my thing except for the original
digital mode---CW).  They don't work as well for wideband and time-varying
signals like SSB.  If you seldom operate CW or digital modes, I doubt you
would find a waterfall very useful.  

I prefer a waterfall only mode for my applications and will probably use
that when Alan eventually makes it available on the P3.  As the P3 stands
now, I maximize the waterfall portion of the display, turn MKR on in the
spectrum area only, center it over a waterfall signal just below and press
QSY to identify the station by ear.  

CW Skimmer is another alternative that uses waterfalls exclusively.  Below
are some screen shots of Skimmer's waterfalls (which are unique in their
ability to show CW dots and dashes over a wide dynamic range of signal
strengths):

http://dxatlas.com/CwSkimmer/

I hope this helps but the best thing is to simply play a game with the
waterfall display.  Try setting Ref Lvl just at the noise floor and see if
you can copy the weakest signals the waterfall detects.  When you can,
you'll be ready to work weak CW DX on the low bands or at VHF.

73,  Bill

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