Re: VLF: Carrier on 8270.00709 Hz

[Markus Vester <markusvester@aol.com>]

Thanks Paul for the background info about coherent stacking.

Anyway a very fine result again for Joe and Paul! And there's hope for further improvement with the lower QRN season, and increased stability and ERP from Joe's side. Looks like a good reason to pursue that north-west cardioid project at DL0AO...  

Best 73,
Markus (DF6NM)

-----Ursprüngliche Mitteilung-----
Von: Paul Nicholson <vlf0403@abelian.org>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: Fr, 1. Sept 2017 2:11
Betreff: Re: VLF: Carrier on 8270.00709 Hz

Jim wrote:

> do these results meet your standard criteria for confirmation?

Barely. There was some cheating at my end.

Because the frequency is not known exactly I had to do some
fiddling to add the two days. The fiddle was to rotate the
phase to align the phases of the two 8270.00709 Hz bins
before adding.

This effectively treats the noise as if it were signal.
This is why the coherent sum was 16 dB and the non-coherent
was 9 dB.

The trouble with this method is that, given enough days to
stack, I can raise a peak on any bin by rotating the noise
to add coherently in that bin.

For comparison, here is what the 25th looks like by itself:

http://abelian.org/vlf/tmp/170828b.gif

I have received VO1NA before on this frequency, back in May:

http://abelian.org/vlf/tmp/170508e.gif

--
Paul Nicholson
--