Return to KLUBNL.PL main page

rsgb_lf_group
[Top] [All Lists]

Re: LF: More EbNaut 137.777 - phase plot

To: [email protected]
Subject: Re: LF: More EbNaut 137.777 - phase plot
From: [email protected]
Date: Mon, 7 Dec 2015 20:26:18 -0330 (NST)
In-reply-to: <[email protected]>
References: <[email protected]> <[email protected]>
Reply-to: [email protected]
Sender: [email protected]
Paul and Markus,
Critique on the sigs are most welcomed.  Getting a decode from Paul
on a dead preamp is very satisfying!

Lets do a repeat of last night's 8 s 2c starting in 5 mins.

73
Joe VO1NA

On Mon, 7 Dec 2015, Markus Vester wrote:

Paul,
 
that's an interesting phase plot! Although it's probably hard to completely 
rule out a contribution from TX oscillator drift, the 3.5-cycle day-night 
change seems quite plausible.
 
Attached is a plot from a recent Loran-C operation from Wildwood, NJ. The top 
plot shows signal strength in two ways (red is the total received pulse energy, 
magenta the narrowband 100 kHz amplitude). The blue plot is continuous phase, 
also showing a similar 3.5-cycle phase advance during the morning hours. Given 
the larger distance (6595 km) and lower frequency (100 kHz), this is obviously 
a very nice match to your VO1NA result.
 
All the best,
Markus (DF6NM)

 
-----Ursprüngliche Mitteilung-----
Von: Paul Nicholson &lt;[email protected]&gt;
An: rsgb_lf_group &lt;[email protected]&gt;
Verschickt: Mo, 7 Dez 2015 12:27 am
Betreff: Re: LF: More EbNaut 137.777 - TA slot

It was a few hours before I got to the rx to retrieve the
battery so it continued on an almost dead battery and recorded
two more messages.

VO1NA 2015-12-05/06 16K21A 5S 5C QRO

 start  Eb/N0  Freq

 13:30  13.0   -222 uHz
 15:00   3.1   -256 uHz
 16:30   3.9   -482 uHz
 18:00  15.1   -558 uHz
 19:30  17.3   -228 uHz
 21:00  14.2   -330 uHz
 22:30  18.7   -262 uHz
 00:00  14.8   -253 uHz
 01:30  17.0   -293 uHz
 03:00  22.4    -41 uHz
 04:30  20.8   -208 uHz
 06:00  13.0   -216 uHz
 07:30  17.0   -276 uHz
 09:00   3.1    +20 uHz

Partial reception at 10:30 gave enough to measure +3 uHz.

I was able to measure the phase over the entire 21 hour
recording in 5 minute averages:

 http://abelian.org/vlf/tmp/151206a.gif

This looks to me like propagation, not drift of the tx
oscillator.  It's a pretty typical diurnal.  I'm plotting
phase measured at a frequency offset of -255 uHz.

I think that Joe's oscillator is actually doing very well and
we are seeing mostly the effect of propagation.  The phase ends
up nearly where it started and the total day/night change is
about -1250 degrees or about -3.5 cycles.
--
Paul Nicholson
-- 
<Prev in Thread] Current Thread [Next in Thread>