From: "Mike Dennison" <mike.dennison@ntlworld.com>
To: rsgb_lf_group@blacksheep.org
Date: Fri, 09 Jul 2010 10:00:30 +0100
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Subject: LF: TA DX on 137kHz/9kHz?
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Warren is right to say that transatlantic QSOs on 137kHz have been=20
rare but he underestimates the facts.

There have been around ten two-way contacts between Eu and NA, all=20
with VE1 or VO stations. Successful UK stations include G0MRF, G3LDO,=20
G3AQC, M0BMU and myself. I think G3YXM may also have made a two-way.=20
M0BMU has made it using several different modes, including WOLF. To=20
this list, I believe you can add DF6NM and CT1DRP. At least 250mW ERP=20
has been required.

Several others in G, as well as stations in F, DL and PA have made it=20
one way to the USA (most Ws are not licensed for two-way contacts). I=20
am sure I have missed out some people here.

One of the main difficulties of a two-way LF QSO is having good=20
propagation for long enough - several hours. This is made much worse=20
on 9kHz by the need for extremely large bit lengths. Even if the path=20
losses could be overcome, a new QSO protocol would have to be=20
invented.

Good luck to the experimenters - just because it seems impossible,=20
there's no reason to stop trying.

Mike, G3XDV
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D

> Well lets start by looking at the success of stations on 137kHz -
> pretty dismal actually.
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> I know that there was a TA contact on 137 10 or more years ago between
> the late Larry Kayser VA1LK and G0MRF but I don't think there's been
> anything since.   My experimental station WD2XGJ is copied nearly 100%
> of the time in Europe, I run 4W ERP and QRSS 60 though QRSS 3 has made
> it across and I believe that F1AFJ has reported that my signal is
> audible on quiet winter nights under good conditions.  I have only
> copied 1 station from across the pond - the late G3AQC on 137 - I have
> a perfect "O" copy of "AQC" in QRSS 60 from Laurie.
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> Very few stations put out a decent signal and the 1w ERP limit in EU
> is just too low for reliable copy, combine that with the fact that
> many amateurs in the UK aren't even sure if they should be making
> foreign QSOs and the result is nada zilch zero !
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> For 9kHz you would need both stations using kite or balloon supported
> aerials - there the hold up will be with the aviation authorities.
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> Somebody should definitely go for it, but I wouldn't underestimate the
> difficulties!
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> I suggest we start a pool everybody kicks in a few
> dollars/pounds/euros for a prize for the 1st stations to make a
> verifiable TA contact (I will personally kick in some money and I'm
> not  too concerned about having to pay out!)
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> --=20
> 73 Warren K2ORS
>                 WD2XGJ
>                 WD2XSH/23
>                 WE2XEB/2
>                 WE2XGR/1
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>=20
>=20
>=20
> On Thu, Jul 8, 2010 at 12:26 PM, Alan Melia
> <alan.melia@btinternet.com> wrote: > Hi Stefan, Mmmm I suppose I put
> my head right into the noose there :-)) > > I think this is a
> difficult one. I am sure the ideal time would be just > before sunset
> in Canada or just before dawn in Europe. That is not much of a > help
> as flying kites at those times is not really feasible =A0:-)) =A0 Thinki=
ng
> > more generally I would say the best time in a daylight path might be
> mid-day > at mid path.....but that is only a "gut feeling". But in
> daytime, summer > might be better for daytime propagation than winter
> (not allowing for > seasonal noise variation) ......I'm ducking and
> diving and hedging by bets > :-)) > > It could be Paul's waveguide
> propagation equations would give helpful > answers. If only to
> calculate the approximate signal levels to compare with > the previous
> tests. Its 4 times further that suggest 16 times the ERP or >
> "capability" of the system. Hopefully if the VLF effect helps it might
> only > need be nearer to 6 to 8dB. There may also be a limitation to
> how narrow a > bandwidth you can use on reception on a path of this
> length. > > I am watching with interest, this is quite a new area, and
> you can't beat > experimentation. If that don't fit the theory.....
> you have to devise a new > theory ....not junk the measurements,
> because you cant argue with > measurement. > > Best Wishes > Alan
> G3NYK > > ----- Original Message ----- > From: "Stefan Sch=E4fer"
> <Stefan.Schaefer@iup.uni-heidelberg.de> > To:
> <rsgb_lf_group@blacksheep.org> > Sent: Thursday, July 08, 2010 1:23 PM
> > Subject: VLF: TA DX on the dreamers band? > > >> Alan, >> >> Which
> time (UTC) would be your recommendation for trying a transatlantic >>
> DX reception on 9 kHz, say to canada? >> Any ideas? >> >> Other
> experts are asked as well here! >> >> >> > > >
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