[amsat-bb] CW timings for amateur radio satellite beacons

[Douglas Quagliana]

Hi Jim,
   Yes, WPM is the standard, but WPM alone doesn't tell you exactly
how long the dits, dahs and delays are (see, for example, Farnsworth).

   What I am trying to do is determine if a given recording has any CW
telemetry in it and at what frequency, not just to get the telemetry but
also to perform Doppler measurements.  For example, HO-68 sends the
CW telemetry and it always starts with "BJ1SA XW XW" and always
ends with "XW XW". These are always sent at the same speed with
the same spacing. The telemetry values in between change, obviously,
but you can calculate a minimum and maximum amount of time for the
telemetry to be sent so you can place some limits on how long after
"BJ1SA XW XW" you should find the trailing "XW XW".  If you see both
of these, then you know that you have found CW telemetry from HO-68.
Even if the signal is too weak to get all of the telemetry, you could still
use the frequency that you found "BJ1SA XW XW" for Doppler
measurements.

   But in order to get a computer/DSP algorithm to look for "BJ1SA
XW XW" you need to specify exactly how long each dit, dah and delay
lasts so that the computer knows what to look for.  The more accurate the
measurements of dits, dahs, and delays, and the longer the CW sequence
that you know for sure, the further into the noise you should be able to
detect the CW signal.  Now for HO-68, it looks like a dit is 80
milliseconds,
dah is 240, and the delays are 80, 400 and 720 milliseconds.  I found these
timing values and I was hopeful that someone had compiled a list of CW
timings for other satellites that send CW telemetry.  I hope this explains
my request.
73,
Douglas KA2UPW/5

On Mon, Jan 28, 2019 at 2:21 PM Jim Walls <jim at k6ccc.org> wrote:

> On 01/27/2019 13:14, Douglas Quagliana wrote:
> >     I am looking for exact dit time, dah time, intra-letter timings,
> > inter-letter timings and inter-word timings for CW beacons from amateur
> > radio satellites.  For example, AO-999, dit time 52 milliseconds, dah
> time
> > 156 milliseconds... and so on.
> >
> >     Is there a comprehensive list that gives precise timing information
> for
> > the CW beacons sent by various amateur radio satellites?
>
>
> My guess is that no one has even considered such a thought.  mSec is not
> exactly the most common timing for CW speed - WPM is.  You might state
> what you are trying to accomplish.
>
>
> --
> 73
> -------------------------------------
> Jim Walls - K6CCC
> jim at k6ccc.org
> Ofc:  818-548-4804
> http://members.dslextreme.com/users/k6ccc/
> AMSAT Member 32537 - WSWSS Member 395
>
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