Re: LF: LF EbNaut test from JN80 on 137370

[Andy Talbot <andy.g4jnt@gmail.com>]

OK

This file  http://www.g4jnt.com/DownLoad/DCF77_TuningTest.WAV    was recorded at 31.25Hz sampling rate and is from the 77.5kHz time signal (MSF is off the air at the moment, just when I wanted a stable test signal typical !!!!!!!)

I started with the tuning dial showing 5Hz high (effective LO = 77505Hz) , so the IF / baseband coming out was 5Hz low, at 995Hz audio from the converter  and at -5Hz in the data stream.   This was then stepped down  1Hz at a time, at roughly one minute intervals so the resulting output frequency  moved UP over the 11 minute interval, stopping with the tone/baseband data 5Hz HIGH in frequency with the tuning showing 77495Hz

Reading the file into SpecLab shows a plot going from bottom left to top right, with the left hand, lower frequency terms having  earlier time stamps.  This plot is the same direction as the one I had on screen during the recording.

So it looks as if my I/Q saved to Speclab compatible .WAV format is the correct way round.

Andy  G4JNT

On 10 December 2015 at 12:00, Paul Nicholson <vlf0403@abelian.org> wrote:

Andy wrote:

> I'll check my generated .WAV files via the waterfall plot
> in Spec Lab to make sure the I/Q is the right way
> round.

Yes, here I will check vlfrx-tools, I think it's the right
polarity but maybe not?   I notice when I rx I/Q from an
RTL2832 SDR I have to invert Q to get the sidebands the
right way round which is suspicious.

--
Paul Nicholson
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