Re: VLF: 300 mA on 8270 Hz

[Paul Nicholson <vlf0403@abelian.org>]

I used Alpha signals to get a rough calibration of the E-field
rx and I retrospectively apply this to the recent recordings.

Below are the daily results already reported for the 16K21A
12 char message just using H-field:

 2017-09-22: +0.4 dB phase 126.0 list rank 8225;
 2017-09-23: +1.6 dB phase 131.0 list rank 0;
 2017-09-24: +0.3 dB phase 134.0 list rank 242;
 2017-09-25: +2.2 dB phase 127.2 list rank 0;
 2017-09-26: +1.2 dB phase 132.8 list rank 0;

Stacking gives Eb/N0 = +7.7 dB.

Now with E-field as well:

 2017-09-22: +3.7 dB phase 134.9 list rank 0;
 2017-09-23: +5.4 dB phase 139.8 list rank 0;
 2017-09-24: +1.1 dB phase 135.9 list rank 0;
 2017-09-25: +4.9 dB phase 133.9 list rank 0;
 2017-09-26: +2.8 dB phase 139.1 list rank 0;

and stacking the five days is 10.7 dB.

By adding in the E-field, the antenna pattern is changed
from a figure-8 to a cardiod.  We might expect to gain 3dB,
or more if a lot of the background noise is coming off the
back of the beam.

Some days, not so much improvement, depends where the noise
is coming from.

But generally, you can see that it is well worth the effort
of 3-axis reception.

Looks like I haven't got the E-field phase calibrated quite
right, calibrated at 11904 Hz, there will be some few degrees
phase shift at 8270 Hz.

This afternoon I will try the 100 char message with 2 repeats
so far...

--
Paul Nicholson
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