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Date: Sun, 10 Apr 2011 16:52:33 +0200
From: wolf_dl4yhf <dl4yhf@freenet.de>
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Subject: Re: LF: Re: GPS Sync
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Hello Stefan,

Indeed you would need a soundcard with stereo input - one channel for=20
the PPS (with NMEA added, if required), and the other for the VLF=20
receiver (or any other signal to be analysed). If the PC's system time=20
can be guaranteed to be less than 0.5 seconds off the true value, NMEA=20
would not be required because in that case, the software could 'guess'=20
the right time belonging to the rising edge of the GPS sync pulse. But=20
decoding the NMEA sentences along with the precise pulse leaves nothing=20
to fate, and such a system will work without internet sync'd time, etc.


Am 10.04.2011 14:16, schrieb Stefan Sch=E4fer:
> Wolf,
>
> Does the Rockwell Jupiter TU30 GPS module (used by DF6NM, OE3GHB and=20
> me and others) provide this NMEA informations too?=20

I don't know, but most likely, yes. If you have the Jupiter's tech=20
specs, you can find out if the unit sends NMEA through the serial=20
output, or if it can be convinced to do so. Again, it's not ultimately=20
necessary to have the NMEA strings (with date+time) but it would be very=
=20
handy for some applications (consider portable operation w/o internet link=
).

> And how will we feed the informations to SpecLab? You mentioned the=20
> soundcard, but how is this possible?=20
As mentioned on the website - see link in my earlier post. All it takes=20
is a resistive voltage divider / adder.
> We would at least need a stereo soundcard, right?
Unfortunately, yes. It you be too difficult to 'subtract' the GPS=20
(PPS+NMEA) signal from the analog signal fed into the same soundcard=20
channel.

73,
   Wolf  DL4YHF .