Message-ID: <495279D4.9050603@telus.net>
Date: Wed, 24 Dec 2008 10:05:08 -0800
From: Scott Tilley <sthed475@telus.net>
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Subject: Why WSPR when you can SHOUT! was Re: LF: wspr
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Mal

WSPR was NOT designed for VHF/UHF and again if you could read you'd know 
that after you had read the documentation I referred you to.  It was 
designed specifically for HF use in a high QSB environment and it works 
very well there.  In fact, it was designed with 30m in mind and the QRPP 
beacons that operate there.  I won't bother explaining further as you 
don't seem to get the basic premises of signal theory and the techniques 
employed for the design rationale of the mode. 

Also have a look here for more info on WSPR and the rationale for the mode:
http://wsprnet.org/drupal/

Before I will engage you further in a dialog about this or any other 
mode I suggest you do some homework and learn how these modes work.  
Like learning CW it takes time and dedication to understand the 
technical and operating requirements for these modes.  Just because you 
can pound a key doesn't mean you have the right stuff to make any form 
of meaningful judgment about this topic.

I suggest you stop wasting bandwidth here and do some learning.   And 
then join the dialog with something meaningful.

73 Scott
VE7TIL


 

mal hamilton wrote:
>
> I did not ask a question about filtering !!!!!!!!!!!!!!!!!!
Oh but you did old man. 

> What I said was why use SSB mode which is 3 khz wide for a 6hz/200 hz 
> wide signal when one could take advantage of the receiver narrow CW filter
We do!  But it isn't necessary most of the time!!!!  I told you why 
earlier...  I use my 300Hz filter most of the time with WSPR to keep LID 
CW ops out of the passband.

> , and of course this is filtered further by manipulation of the 
> soundcard by software. This is old hat technology and not new.
> WSPR was engineered for VHF/UHF with plenty of frequency spectrum 
> available and not MF/LF

WRONG!
> squeezed into a 3 khz slot along with other more robust modes
> I am not opposed to any particular transmisson MODE but merely 
> pointing out that the advantage claimed by some for WSPR is not 
> justified in some cases and my recent observations indicate that I 
> could have read the transmitted signal had it been ON/OFF CW, instead 
> I had to wait ages for the signal to improve before text printed. This 
> was the case last night with WE2XGR where the 2 minute interval trace 
> was good enough to be read in on/off mode CW but not strong enough to 
> print most of the time due to slow fade(QSB)

You don't have enough experience or knowledge based on you comments to 
intelligently comment on this in my opinion. 
> I might even research WSPR further for comparison purposes but I 
> cannot imagine that I will get a print out first before I see a trace.
You have pretty high expectations for the mode!  I have never heard of 
any mode that you could decode without being able to see some form of 
trace.  Perhaps you're one of these CW op types that has ESP and has 
QSOs with the little DX stations in your head?  What don't like the fact 
there is something in the world that can quantify reality?

>
>
>
> G3KEV
>
> ----- Original Message ----- From: "Scott Tilley" <sthed475@telus.net>
> To: <rsgb_lf_group@blacksheep.org>
> Sent: Wednesday, December 24, 2008 5:00 AM
> Subject: Re: LF: wspr
>
>
>> 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
>>>
>>
>
>
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