[Lowfer] QRSS Alternative

Tue, 01 Apr 2003 16:21:22 -0500

Paul

I can run a capture tonight and post it for all to see. One capture is worth a
....

Jay

[email protected] wrote:

> Hello Gary,
>
> Thanks for the reply and a chance to explain some of the things that I
> surely have left out.
> ----- Original Message -----
>
> > Have you done a Google search on DFCW AMATEUR RADIO ?  You will find lots
> of
> > comments about using it, but in amongst the hundred or so hits will be a
> few
> > discussions on the hows and whys and pitfalls.  The DF is dual frequency
> and
> > easier to generate and would use less bandwidth.  How do you generate your
> 5
> > RF frequencies?  If you are using a PC and soundcard, you need a SSB
> > transmitter with good linearity vs a simple CW tx.  Or go to a DDS chip
> and
> > a micro-controller (which is what I would do)?
>
> Yes I have done the search and have  found many articles about DFCW.  Some
> versions seem to use no spacing and only 2 frequencies.
> This gets confusing when you have several dots or dashes together along with
> band conditions fading.  This method seemed easier from the persective of
> the position of the element determines the value of the element.  By using
> the 5 freq I was able to eliminate all of the inter element spacing and use
> only inter letter spaces.  Hence the 4 dots in a row would look like a
> squarewave as they alternated between .0, .2, .0, .2
> To further decrease the ime to send an ID the inter letter spacing of 1
> element could be decreased further and still be effective.
>
> I am using a HP 3856b  selective level meter as the basis for the
> transmitter.  These units can easily be locked to a 10 Mhz GPS reference and
> have a convienient  tracking generator  output on the back at 0DBM in 50
> Ohms.  This unit can also be instructed to move in .1 HZ increments.
>
> I alraedy had the HP SLM so I decided to write to it via the HPIB input in
> the back.  This was a little harder than I thought it would be at first and
> I still have not master even this small amount of code.  In addition the
> element length and dot to dot spacing may leave some room for improvement in
> clarity.
>
> After getting accustomed to it,  I have been able to read the code easily
> with out knowing the actual frequencies or spacings of the xmitter.
>
> Did I get everything?   I wish I could post the JPEG I have so you guys
> could get a look at it.
>
> Please more comments.  BTW  The "USA"  beacon ID takes 11 min using QRSS 60
> to ID.
> W1VLF takes 27 minutes  as apposed to 60 minutes using standar 3:1 QRSS.
>
> This advantage may just put that callsign in the midst of a prop peak where
> a 1 hour ID would not have survived.
>
> Thanks for the comments.
> Would wyou like me to email a JPEG of the USA capture?
>
> Paul Cianciolo
> W1VLF
> Beacon  " USA"  185.298.00 Khz
>
> > Why use 5 vs 3?  A dot freq, a dash freq and a space freq.  With fixed
> > timing formats, we know when the changes are "allowed" to happen, i.e.
> RTTY
> > runs at a few speeds, right? 45.45, 75, 100 I think.  No one is sending at
> > 82.3 or 69.1.  If you are on the dot freq 3 time periods, and then got to
> > space, it is an S.  If it goes to the dash freq for 1 period then space,
> it
> > is a V.  The 3 to 1 and inter-element spacing was for hand keying and
> human
> > ear decoding.
> >
> > But yes, there is merit in NOT having dashes 3 times longer than dots and
> > being able to tell dropouts from element spacing.  What way to do it is
> the
> > question <G>
> >
> > Gary WA6DTX
> > ----- Original Message -----
> > From: <[email protected]>
> > To: <[email protected]>
> > Sent: Wednesday, March 19, 2003 7:43 AM
> > Subject: [Lowfer] QRSS Alternative?
> >
> >
> > > Hello Folks,
> > >
> > >
> > [snipped]
> >
>
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