LF: Vlf ot Penguins and awesomes

[Laurence KL7 L <hellozerohellozero@hotmail.com>]

VLf buffs 

Im presently  Beta testing a Stanford VLF standard 5 turn 1 mH 1 ohm 10m sided loop array and a test LNA. Im struggling with data on the transformer which says its primary impedance is 10mH turns ratio of 16 to match the appx 300ohm input Z of the bipolar device. I pinged the author whose  phd dissertation it was for actual design material but presently "playing" with a pot core with 10mH primary and 40mH secondary. Anyone have any info as this appears to a standard "transformer" but critical to the LF attributes and sensitivity for the awesome and other penguins designs out there

I think in going to be limited on 8kHz due to in ground dog fence pulsing which now way up in level compared with the probe. But the main loop is affixed near 0deg...

Ill continuing investigating...

Laurence KL7L

On Feb 7, 2016, at 12:10 AM, Markus Vester <markusvester@aol.com> wrote:

After the sequence, the carrier was on 8270.0025 again from 5:25:20 to 8:35. Now QRT.

 

73, Markus

 

-----Ursprüngliche Mitteilung-----
Von: Markus Vester <markusvester@aol.com>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: So, 7 Feb 2016 5:14 am
Betreff: Re: VLF: EbNaut 8270.1 Sunday

Just started another sequence with same parameters, running 04:00:02 to 5:25:22 UT.

 

73, Markus

-----Ursprüngliche Mitteilung-----
Von: Markus Vester <markusvester@aol.com>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: Sa, 6 Feb 2016 11:52 pm
Betreff: Re: VLF: EbNaut 8270.1 Saturday

Thanks once again Paul for your outstanding work. It is great to see what you can make of such a feeble signal, so close to the ultimate SNR limit. Thanks also Lubos and Stefan for continuously running and maintaining your sensitive and useful grabbers.

 

Unfortunately VLF transmissions from here depend on a number of circumstances, and they are not easy to predict and announce beforehand. When I don't have to go to work, and if the wind stays calm, and the weather is dry, and the static background is low, and none of my neighbors complains about the beeps, I might try another one tonight or tomorrow ;-) 

 

Best 73,

Markus (DF6NM)

 

 

-----Original Message-----
From: Paul Nicholson <vlf0403@abelian.org>
To: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Sent: Sat, Feb 6, 2016 1:48 pm
Subject: Re: VLF: EbNaut 8270.1 Saturday

> Frequency: 8270.100 Hz,
> start time 9:00:02,
> 5 characters, 8K19A, 16 bit CRC, 10 second symbols,

Decoded 'DF6NM' at Eb/N0 = +0.3 dB, BER 36.5% which
is 67% of capacity.

Carrier 10:25 to 11:25 UT had flux density 0.05 fT
and S/N 11.4 dB using H-field alone. I combined
with E-field to get a couple more dB for the decode.

--
Paul Nicholson
--