Message-ID: <57FCE651.7020809@posteo.de>
Date: Tue, 11 Oct 2016 15:17:05 +0200
From: DK7FC <selberdenken@posteo.de>
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; de; rv:1.9.1.8) Gecko/20100227 Thunderbird/3.0.3
MIME-Version: 1.0
To: rsgb_lf_group@blacksheep.org
References: <157b05f2e7d-a71-85cc@webprd-a60.mail.aol.com> <57FC02C5.10700@posteo.de> <57FCA0EC.3000804@abelian.org>
In-Reply-To: <57FCA0EC.3000804@abelian.org>
Subject: Re: VLF: EbNaut transmissions on lower frequencies?, pre-tests: 6.47kHz
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Sender: owner-rsgb_lf_group@blacksheep.org
Precedence: bulk
Reply-To: rsgb_lf_group@blacksheep.org
Content-Length: 1775
Status: O

Hi Paul,

You're almost there.
It would be interesting to see the recontructed spectrum peak then. Give 
me as many informations as you can about the signal, because, i must 
admit, i am not 100% sure that the transmission went well all the time. 
Maybe this is an explanantion for the partial decode. It could be that 
there were times where the feedback signal on the TX soundcard became 
stronger than expected. And this could have disturbed the pps tracking 
occasionally. In the colour plot generated from the signal as received 
on the tree, there were just two colours, as expected. But maybe an 
unwanted 180 deg phase shift happened from time to time? Just a 
speculation. This did not happen on 2970 Hz. But on 6470 Hz the voltages 
are higher and maybe the levels were not calibrated properly.
If there will be no clear result, i can repeat the last transmission. 
But you are very close to the result as one can see.

My carrier, which is still on the air, will give more details about the 
signal stability. However this time there is no trace in Italy yet :-(
MF WSPR is easier, i can tell you ;-) But not a challenge like that!

73, Stefan

Am 11.10.2016 10:21, schrieb Paul Nicholson:
>
> Overnight, the decoder turned up
>
>  'DK7FC4273 U8Z  '
>
> at Eb/N0 = -1.1 dB with 40.1% BER.   It is still running.
>
> > Thant's exciting! You will get the result, i know it :-)
>
> This is a great challenge, the signal is about 18 dB in 6uHz,
> which is about -68dB in audio bandwidth after sferic blanking,
> about -88 dB before the blanker.   This is over 10dB weaker
> than Dex's transatlantic messages.
>
> I see you put out some carrier on 6470.0025 Hz, later I will
> look at that to fine tune the beam heading and antenna EQ.
>
> -- 
> Paul Nicholson
> -- 
>