[Lowfer] PSK31 vs. CW

[John Matz]

Hi all
PSK31 in the BPSK mode needs 6 to 10 dB S/N in a 30 Hz bandwidth.  CW at 12
wpm or CCW needs 6-10 dB S/N in about a 10 Hz bandwidth as I recall.  If
one copies "by ear", he'll need about a 30 Hz bandwidth too.  So PSK31 at 1
watt continuous is about the same as CCW on-off keyed at 1 watt on (0.5
watt average).  Maybe CCW at 12 wpm (10 baud) electronically detected is at
most 5 dB better.  BPSK is commonly run at 10 baud too, so it's 5 dB better
than PSK31 at 31 baud.  The big plus on BPSK is the even slower data rates
possible and the "deep grabs" that allow even more effective noise
reduction (another 3 to 10 dB).  

I think that's a pretty close description.  Others?

John Matz KB9II

----------
> From: Andre' Kesteloot <akestelo@bellatlantic.net>
> To: AMRAD Tacos <tacos@amrad.org>; lowfer <lowfer@qth.net>
> Subject: [Lowfer] PSK31 vs. CW
> Date: Wednesday, November 10, 1999 7:45 PM
> 
> Interesting.  I thought all along that PSK31 was going to offer an
advantage
> over CW, but the message below does not appear to support that theory
> Andre' N4ICK
> ************************
> Dave wrote:
> 
> > Dear all.
> >
> > Apologies to all those who wondered what the warbly carrier around
136.2kHz
> > was these past few evenings (especially to those I accidentally QRM'd
by
> > coming up on 136.5 tonight, oops..). It was PSK31 tests with OH1TN, he
asked
> > me to use the low end of the band as the top end is too noisy over
there.
> > Tonight we finally made it and the first PSK31 QSO from G/OH was made
at
> > 2240 on 10/11/99. This is also the longest distance worked on PSK31 on
LF,
> > about 1800km I think.
> > If anyone else wants a go I'd be happy to try but it appears you have
to
> > have a pretty good CW copy before it will work.
> > Reino also says to look out for OH3LYG who is now QRV on CW.
> >
> > 73, Dave G3YXM.
> 
> 
> 
> 
> 
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