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Message-ID: <002a01cb26c9$151041a0$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><001101cb26bb$48ea5e10$4001a8c0@lark> <AANLkTimWl17mM3DTHmlnfiNyEtwrCLe7DsuhCHSh8Um7@mail.gmail.com>
Date: Sun, 18 Jul 2010 23:32:14 +0100
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Subject: Re: LF: 136.96kHz testing
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Hi Roger you may just have rejuvenated my interest :-)) previously my
nearest LF neighbour was Jim, I dont remember whether Chris G3XVL was on
when I last listened. Chris is in Ipswich of course. The gear is still in
place it just wants connecting together and the audio connectons through the
house re-making....I try to keep the PC as far from the aerial and RX as
possible. There was a lot of local interference at one time which was the
main reason for losing interest.......it may still be around or even be
worse by now.

Alan



----- Original Message ----- 
From: "Roger Lapthorn" <rogerlapthorn@gmail.com>
To: <rsgb_lf_group@blacksheep.org>
Sent: Sunday, July 18, 2010 10:18 PM
Subject: Re: LF: 136.96kHz testing


> Alan,
>
> Yes, that ties up with the signal being stronger with the E-field probe
held
> above my head. Agreed, that lambda/2pi is around 350m, so I'm only just
> exiting the near field region. Tomorrow I may do some QRSS3 tests locally
to
> see if I can see the QRPp 136kHz signal a few kms away with E-field probe
> and FT817.
>
> When I get properly started on the band - with a "real" (up in the air)
> antenna and some more power - I'd appreciate some reports from you Alan.
You
> are indeed at a useful distance from me.
>
> It may take me some time to get things together but 136kHz is a project
that
> is slowly gathering some momentum here now. With HF being nothing to get
> excited about at the moment, I think 136kHz will be worth a try.
>
> 73s
> Roger G3XBM
>
>
>
> On 18 July 2010 21:52, Alan Melia <alan.melia@btinternet.com> wrote:
>
> > 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
> > >
> >
> >
> >
>
>
> -- 
> http://g3xbm-qrp.blogspot.com/
> http://www.g3xbm.co.uk
> http://www.youtube.com/user/g3xbm
> G3XBM    GQRP 1678      ISWL G11088
>