[Elecraft] P3 and Digital Mode Operation

[Claude Du Berger]

Lyle, could we use the P3 as a X-Y Scope to monitor RTTY signal
as on MMTTY?

73 de VE2FK

  ----- Original Message ----- 
  From: Lyle Johnson 
  To: elecraft at mailman.qth.net 
  Sent: Monday, March 29, 2010 2:40 PM
  Subject: [Elecraft] P3 and Digital Mode Operation



  I've been testing the P3 < URL:http://www.elecraft.com/news.htm > for a 
  while now, and it has a really nice feature for Digital Modes that my 
  other panadapter solutions lack.

  The P3 has a SPAN control.  This sets the width of the spectrum display 
  in kHz.  When looking at a busy band, for example during last weekend's 
  contest, this made it pretty easy to spot activity on a relatively quiet 
  band (15m) or a hole on a very busy busy band (20m).  This isn't much 
  different than other panadapters, just more convenient.

  However, let's say you decide to operate a digital mode, such as PSK 31.

  Dial down the SPAN to ± 3 kHz.  Suddenly, the display looks like the 
  usual "waterfall" you are accustomed to when using DM780, MIXW, 
  MultiPSK, CocoaModem, etc.  You can easily distinguish individual 
  signals, and see the modulation on them.  It is extremely simple to then 
  set the marker on a signal, tap the control to re-tune, then then tap 
  the SPOT button on the K3 to get it nailed.  You are now ready for a QSO 
  using PSK-D mode.

  This same feature is also very useful when operating RTTY.  Further, the 
  P3 lets you see nearby signals in fine detail even when you have the 
  K3's dual passband feature turned on.  Use of such narrow filtering on 
  the K3 restricts the usual waterfall display on the DM780 or MMTTY 
  console, for example.

  And, the P3 doesn't consume PC screen real estate.

  The reason this works so well with the P3 is that as you adjust the 
  SPAN, the P3 automatically adjusts its internal filters, sampling rates 
  and calculations to effectively utilize the display width. If you use 
  the ZOOM control on PowerSDR with LP-PAN, for example, you just get a 
  much coarser display as you zoom in because the sampling rate for the 
  soundcard being used with PowerSDR doesn't automatically adjust as you 
  change displayed bandwidth.  If it did, it has limited rate selections 
  depending on the soundcard being used and its drivers.  Since the P3 
  hardware is purpose-built from the outset to be a panadapter rather than 
  a general spectrum display or a soundcard, it does not have these 
  limitations.

  73,

  Lyle KK7P

  Disclaimer: I work for Elecraft.
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