DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws;
  s=s1024; d=btinternet.com;
  h=DKIM-Signature:Received:X-Yahoo-SMTP:X-YMail-OSG:X-Yahoo-Newman-Property: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=KkQW5ldt4JbWsjCRcBHR18QixVlp7agSSmq7h7+1C5sxwqTpMmRYXaKUubcFKVMuwkiN7twW/OebiNo9/ZAhZutaO1GGcHWFA7TDZCOLZAYC3Byt+3SfC/KlNWBmFGHSFm8B+7p8vq4fsLPUWs9/PwpQMp32v3YShzxeewKfb4A=  ;
Message-ID: <001101cb26bb$48ea5e10$4001a8c0@lark>
From: "Alan Melia" <alan.melia@btinternet.com>
To: <rsgb_lf_group@blacksheep.org>
References: <AANLkTilXGbYPLECD3tdAH6AtWh5w97o5WHhtNvp2TIxD@mail.gmail.com> <AANLkTim5WnnPsH4CD1lrStqKaD9mhOdttdIWV-CFxk23@mail.gmail.com>
Date: Sun, 18 Jul 2010 21:52:28 +0100
MIME-Version: 1.0
DomainKey-Status: good (testing) 
Subject: Re: LF: 136.96kHz testing
Content-Type: text/plain;
	charset="iso-8859-1"
Content-Transfer-Encoding: 7bit
Sender: owner-rsgb_lf_group@blacksheep.org
Precedence: bulk
Reply-To: rsgb_lf_group@blacksheep.org


Hi Roger dont forget the e-field probe has a sensitivity which is related to
its height not the length of the whip. If you are holding a conducting case
the effective height is say 2m , at carrying heigh say 1m the signal
collected will only be half as strong. You are barely out of the near field
at 400m but getting close.

Unfortunately I dont have a an LF receiver and aerial connected up at the
moment, I will have to sort that out because at 50 miles (ish) I would be an
interesting distance for you..

Alan G3NYK

----- Original Message ----- 
From: "Roger Lapthorn" <rogerlapthorn@gmail.com>
To: <rsgb_lf_group@blacksheep.org>
Sent: Sunday, July 18, 2010 8:50 PM
Subject: Re: LF: 136.96kHz testing


> The measured power out from the PA is actually 250mW going into the earth
> electrodes. As a test I connected a PA0RDT designed active
> antenna<http://carc.org.uk//carc_ftp/G3GRO-PA0RDT-Active_Ant.pdf>run
> from a 9V PP3 battery and connected this to the (deaf at 136kHz) FT817
> and went for my walk across the fields. The signal was copyable (not
strong)
> at 0.4km with 10wpm CW. Signal was stronger if I held the E-field probe
> above my head.
>
> Those of you like Mal who work multiple continents on the band will thing
> this is nothing, but it gives me a starting point from which to
> progressively improve my system. I'm just amazed that 250mW into earth
> electrodes 20m apart can be heard Q5 at 0.4km with a 19 inch whip
handheld.
>
> More fun next week...
>
> 73s
> Roger G3XBM
>
> On 18 July 2010 17:14, Roger Lapthorn <rogerlapthorn@gmail.com> wrote:
>
> > *This is the very beginning of my journey onto 136kHz....
> >
> > *For anyone very *very* close to Burwell, Cambs, JO02DG, I'm putting a
QRP
> > 10wpm keyer-generated CW message (later to be changed to QRSS3) out on
> > 136.96kHz CW into my earth electrode antenna. Power from the TX is about
> > 500mW, so ERP is just a few microwatts at most.
> >
> > I'd appreciate reports, but be amazed to get any until I start to run
some
> > more power into a real antenna.
> >
> > 73s
> > Roger G3XBM
> >
> >
> > --
> > http://g3xbm-qrp.blogspot.com/
> > http://www.g3xbm.co.uk
> > http://www.youtube.com/user/g3xbm
> > G3XBM    GQRP 1678      ISWL G11088
> >
>
>
>
> -- 
> http://g3xbm-qrp.blogspot.com/
> http://www.g3xbm.co.uk
> http://www.youtube.com/user/g3xbm
> G3XBM    GQRP 1678      ISWL G11088
>