From: <hvanesce@comcast.net>
To: <rsgb_lf_group@blacksheep.org>
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Date: Thu, 28 Dec 2017 18:10:57 -0500
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Subject: RE: VLF: Finally back on the 58 km band...
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Great results from Stefan, Paul, Jacek, Renato and Wolf; especially interesting because in general groundwave/skywave interference phase noise should be comparatively high at 5170 Hz / 303.8 km, and decreasing with distance through 919.3 km, while (independent of phase interference) signal strength also decreases. Models are not accurate enough to show which of the two effects dominates at this frequency and range span, so these simultaneous measurements of overnight Eb/N0 and phase at 303.8 km, 504.6 km, 881.2 km and 919.3 km, on four successive nights, are quite interesting.

73,

Jim AA5BW
   

-----Original Message-----
From: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Paul Nicholson
Sent: Wednesday, December 27, 2017 9:21 AM
To: rsgb_lf_group@blacksheep.org
Subject: Re: VLF: Finally back on the 58 km band...


Stefan wrote:

 > f = 5170.1000 Hz
 > Start time: 23.Dec.2017  15:30:00 UTC (daily)  > Symbol period: 60 s  > Characters: 3  > CRC bits: 11  > Coding 16K21A  > Duration: 13:04 [hh:mm]

Now with the 4th night.  Good phase and amplitude repeatability, except at Todmorden. The repeats should stack very well.

Todmorden (881.2 km)
--------------------

  23/24 Eb/N0 +10.6 dB phase 43.4, *Decoded*
  24/25 Eb/N0 +11.8 dB phase 45.7, *Decoded*
  25/26 Eb/N0  +3.4 dB phase 32.8, *Decoded*
  26/27 Eb/N0  +3.6 dB phase 54.4, *Decoded*

Bielefeld (303.8 km DL4YHF)
---------------------------

  23/24 Eb/N0 +16.1 dB phase -51.2, *Decoded*
  24/25 Eb/N0 +15.7 dB phase -50.2, *Decoded*
  25/26 Eb/N0 +15.0 dB phase -50.8, *Decoded*
  26/27 Eb/N0 +14.6 dB phase -45.0, *Decoded*

Warsaw (919.3 km SQ5BPF)
------------------------

  23/24 Eb/N0 -4.3 dB phase -37.4;
  24/25 Eb/N0 +2.2 dB phase -13.5, *Decoded*
  25/26 Eb/N0 -3.1 dB phase  -2.5;
  26/27 Eb/N0 -0.2 dB phase -17.4, *Decoded*

Cumiana (504.6 km IK1QFK)
-------------------------

  23/24 Eb/N0 +5.0 dB phase -173.0, *Decoded*
  24/25 Eb/N0 +4.2 dB phase -176.9, *Decoded*
  25/26 Eb/N0 +2.4 dB phase +165.2, *Decoded*
  26/27 Eb/N0 +2.3 dB phase -175.3, *Decoded*

 > I hope your H field RX was further improved now?

As you can see, the problem with H S/N at this frequency is still there.  I can say with confidence it is not the rx and probably not the antenna.

--
Paul Nicholson
--