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Date: Tue, 23 Dec 2008 21:00:33 -0800
From: Scott Tilley <sthed475@telus.net>
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Subject: Re: LF: wspr
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If you could read you would do some research at K1JT's wonderful website:
http://www.physics.princeton.edu/pulsar/K1JT/

Joe has laboured for many a year on similar projects and has written 
much about his application of the art.  What you will find is that 
research into communication theory that started with CW has taken us here...

To answer your specific question the filtering is done in software. The 
DSP is done in your PC, thereby making filtering in the radio somewhat 
redundant unless you have strong neighbours in the passband.  So using a 
wide SSB filter and the radio in USB makes for easy math in ones head.  
Yes, we digital types use our heads from time to time.

Often with modes like JT65 used on EME and now quite popular on HF one 
wants as much bandwidth as possible in the receiver so you can monitor 
up to the entire band in real time.  So lots of raw bandwidth into the 
computer is a good thing...

All BS aside, you may find the technology very interesting to study and 
you may find that what you discover is that the spirit of the CW 
operator of old is alive and well just evolving with the times.

CW will never die as it has a rich history but it shouldn't be allowed 
to impede the growth of new modes and technology.

You should build yourself a Softrock SDR receiver or even a small 
transceiver kit and witness a true revolution in radio technology.  My 
little 40/30m rig allows me to watch the entire band of either in real 
time.  With some new software you can monitor all of the CW QSOs at 
once...  Pretty cool.

Not to mention you can plug a key into the little box and do what you 
love most and work'm.

73 Scott
VE7TIL







 


mal hamilton wrote:
> If recent published info is correct, this specifies a bandwidth of 6hz 
> why is USB with a bandwidth of 3 khz necessary to receive this 
> transmission.
> Surely it would be obvious that CW mode was more appropriate where 
> one could use a narrow filter and dsp processor of a few hertz.
> I have asked this question before but never got an answer.
> g3kev
>