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" <[email protected]>
To: <[email protected]>
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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