DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws;
  s=s1024; d=btinternet.com;
  h=DKIM-Signature:X-Yahoo-Newman-Property:X-YMail-OSG:X-Yahoo-SMTP:Received:Message-ID:From:To:References:Subject:Date:MIME-Version:Content-Type:Content-Transfer-Encoding:X-Priority:X-MSMail-Priority:X-Mailer:X-MimeOLE:X-Antivirus:X-Antivirus-Status;
  b=YFgVsbGP/yOEV+nr+IITMsRDhPWhuhPuZRCbiA9uw3SOiryTLIQRcMDUFCMW09T83MD4jmmg1rVYxnUAY/FggqLepfP/YzDFSsdbjVZKB6oKLhVwpqDnAsms7UT7/vKvXroRg4Ku9Fwleha2XVlH0pQdAshJTAUm0mFoEmJy3UU=  ;
Message-ID: <41D4AB78ABB34782B413399ED4F3481A@gnat>
From: "Alan Melia" <alan.melia@btinternet.com>
To: <rsgb_lf_group@blacksheep.org>
References: <4FE39E8E.8000301@iup.uni-heidelberg.de>
Date: Fri, 22 Jun 2012 00:46:38 +0100
MIME-Version: 1.0
Subject: LF: Re: 15 dB noise drop in 20 minutes
Content-Type: text/plain;
	format=flowed;
	charset="ISO-8859-15";
	reply-type=response
Content-Transfer-Encoding: 8bit
Sender: owner-rsgb_lf_group@blacksheep.org
Precedence: bulk
Reply-To: rsgb_lf_group@blacksheep.org
X-AOL-SCOLL-URL_COUNT: 0  
X-AOL-SCOLL-AUTHENTICATION: mail_rly_antispam_dkim-m019.2 ; domain : btinternet.com DKIM : fail  
x-aol-sid: 3039ac1d60c94fe3b28f0b3b
X-AOL-IP: 195.171.43.25
X-AOL-SPF: domain : blacksheep.org SPF : none


Hi Stefan, this is a function of propagation, I think. It depends on where 
the interference originates. Because there is virtually no skywave 
propagation in the "sunrise dip", no noise is propagated by skywave (> 
1000km) from the east. Where you live you have large cities all round you. 
We get this effect on the edge of Europe as the daylight kills the 
night-time propgation of noise fron the East (there a few big cities or 
industrial noise sources for 3000 km W of Ireland
:-))  )

It was thought at first that this would be the best time for DX, but despite 
trying it didnt work out that way. Mike G3XDV and Brian CT1DRP tried quite 
hard..... but eventually made the qso mid morning, when the noise was up 
again due to increases in daytime skywave!! That is if I remember 
correctly.....it fascinated me as I was just getting interested in LF long 
distance propagation around then. We found evening effects in Nova Scotia 
and I believe similar effects were reported by John W1TAG and  Jay W1VD who 
are very close to the US East Coast.

Alan
G3NYK
----- Original Message ----- 
From: "Stefan Schäfer" <Stefan.Schaefer@iup.uni-heidelberg.de>
To: <rsgb_lf_group@blacksheep.org>; "YV7MAE Maritn A. Echazarreta D." 
<yv7mae@gmail.com>
Sent: Thursday, June 21, 2012 11:22 PM
Subject: LF: 15 dB noise drop in 20 minutes


> Hello Martin, LF,
>
> I'm fascinated by the noise drop on LF which occurs during your sunrise. 
> On your grabber 
> (http://dl.dropbox.com/u/74746618/LF/YV7MAE_LF_Grabber.html ), i can see 
> the noise drops 15 dB within 20 minutes. That means the sun must be very 
> strong so the ionosphere is very quickly ionized. Also the local lightning 
> density must be extreme. All in all it looks like a very sensitive system. 
> But some directivity would be interesting :-)
>
> 73, Stefan/DK7FC
>
> PS: I will be on 136.172 kHz again this night, starting in a few 
> minutes...
>