Re: LF: W4DEX at 8540 Hz in Todmorden

[Markus Vester <markusvester@aol.com>]

Hi Dex and Paul,

great job! That brings back good memories from 2014
http://abelian.org/vlf/tmp/w4dex_140602a.gif
which ultimately led to several transatlantic EbNaut detections.

We'll need to set up new grabber instances at DL0AO for your frequency. Or would you consider QSYing into the "waterhole" near 8270 Hz?

Best 73,
Markus (DF6NM)


-----Ursprüngliche Mitteilung-----
Von: Paul Nicholson <vlf0403@abelian.org>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: Sa, 2. Dez 2017 14:05
Betreff: LF: W4DEX at 8540 Hz in Todmorden

Dex surprised me last night with a carrier on 8540 Hz,
GPS-locked and the ERP would be circa 100uW.

Tx was stable from 21:25, detectable in the UK by 22:30,
and a good overnight signal until 03:00 when Dex planned to
switch off.

http://abelian.org/vlf/tmp/171202a.gif

Signal about 0.1fT and 30nV/m, about 30 electrons worth of
charge on the new E-field antenna. Anything with double
figures is a good amateur signal!

H-field: -27.7 dB in 1Hz, phase -109.4 deg;
E-field: -26.0 dB in 1Hz, phase -108.1 deg;

It's not unusual for the new E-field rx to do better than the
loop rx. Looks like I need to hurry up with the upgrade to
the H rx! I've cleared bench space for the replacement and
parts are on order.

I measured the bearing using three different methods:

Watson-Watt goniometry: 273.1 deg

Poynting vector: 287.5 deg

Tsuruda/Hayashi NPE: 282.3 deg

The great circle bearing is actually 284.6 deg.

NPE should be the most accurate method - no polarisation error
but relies on precise relative phase measurements between the
three channels.

--
Paul Nicholson
--