Re: 110A and 4485 - WWVB

Patrick Lindecker
 

Hello Roger,

12000 Hz is the internal sampling frequency. Modern cards are 48 KHz sampling frequency and not 44,1 KHz as 20 years before. They are now, in general, quite precise.

You can test your sound card: click on the "Adjustments" menu button, select the "Determination of the RX/TX sound-card sampling frequencies" option and push on the "Determination of the 48 KHz RX sampling frequency (test on 3 minutes)" button.
If the sampling frequency is close to 48000 Hz, better is to select 48000 Hz.

At the end of the test, click on "Return".

73
Patrick

-----Message d'origine-----
De : multipsk@groups.io [mailto:multipsk@groups.io] De la part de Roger
Envoyé : mercredi 23 janvier 2019 02:03
À : multipsk@groups.io
Objet : Re: [multipsk] 110A and 4485 - WWVB

Patrick,

Do I understand correctly that to use the 110A mode in Multipsk the soundcard must be (or optimally should be) running at 12000 Hz sampling rate? Or are multiples of that OK (e.g. 48,000, 96,000)?

Thank you.

Roger

On Jan 19, 2019, at 1:38 AM, Patrick Lindecker <f6cte@...> wrote:

Roger and all,

If you click on the "Frequencies" command on top of the RX/TX screen,
you will have all the frequencies (as far as I know them) for all the
Multipsk decoded modes.

For 4485 it is only transmitted a repeated test sentence (by French or
Italian navy if I remember well). Nothing really exciting.

For LF transmissions, apart from Multipsk, you have also time stations
decoded by Clock (for example WWVB, see below, extracted from the
paper from

"WWVB: A Half Century of Delivering Accurate Frequency and Time by Radio").

"NIST radio station WWVB, which today serves as the synchronization
source for tens of millions of radio controlled clocks, began
operation from its present location near Fort Collins, Colorado at 0
hours, 0 minutes Universal Time on July 5, 1963. Thus, the year 2013
marked the station’s 50th anniversary, a half century of delivering
frequency and time signals referenced to the national standard to the
United States public. One of the best known and most widely used measurement services provided by the U. S.
government, WWVB has spanned and survived numerous technological eras.
Based on technology that was already mature and well established when
the station began broadcasting in 1963, WWVB later benefitted from the
miniaturization of electronics and the advent of the microprocessor,
which made low cost radio controlled clocks possible that would work indoors. "

73
Patrick


-----Message d'origine-----
De : multipsk@groups.io [mailto:multipsk@groups.io] De la part de
Roger Envoyé : samedi 19 janvier 2019 00:16 À : multipsk@groups.io
Objet : [multipsk] 110A and 4485

I would like to try out these modes.
For testing the RX function, does anyone know of frequencies where
stations are transmitting the submodes that Multipsk can decode? LF
stations that can be received in west coast Canada would be best.
Thank you.



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