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LF: VLF remote stream with GPS locking

To: [email protected]
Subject: LF: VLF remote stream with GPS locking
From: DK7FC <[email protected]>
Date: Mon, 11 Apr 2016 00:35:26 +0200
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I've now configured and installed a 10 EUR cheap NEO-6M GPS module on the tree. It consumes about 45 mA at 3.3V, i.e. abt 0.15W. This can be accepted and i can switch it off remotely if not needed. The module feeds 1 pps + NMEA into the right soundcard channel of my stereo soundcard (one of two) which is running on the Raspi Pi 2B. Some images:
The sound data is streamed to the PC(s) in the shack where the 1 pps to NMEA is read by SpecLab to compensate the soundcard drift and eventual phase glitches.
The Alpha trace at has no glitches any more, except the original one at 21UTC.

However there seems to be some phase jitter. Unfortunately the config data of the module was not saved but i assume that in unintentionally short cut the backup battery while carrying the module to the tree in a plastic bag containing other electronic parts. Now the NMEA data collidates with 1 pps (again). I will soon re-configure the module and hope the jitter is gone then.
Does someone ever played with SpecLab and NMEA and know the jitter effect and its reasons?

But, now i'm running a 47 uHz, 'DFCW-60000' instance and another one generating txt files for an eventual decode of DJ8WX' VLF EbNaut transmission tomorrow morning. The VLF RX loop is pointing into his direction!

Ah, yes, and, there is some QRM in the wideband spectrum during sunny afternoons. This is my solar charger which was still re-designed to regulate (clipping) the voltage depending on the temperature. The VLF loop is just in 3m distance to that regulator and cables. I will further improve...

Now let's hope for Uwe :-)

73, Stefan

Am 10.04.2016 22:30, schrieb [email protected]:

the carrier is on the air.
the message:

start 2016-04-11 07:00:00

coding 8K19A

CRC 16

period 30

length 3

duration 03:28:00:00

Have fun

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