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Date: Sun, 27 Dec 2009 23:03:34 +0000 (GMT)
From: ALAN MELIA <alan.melia@btinternet.com>
To: rsgb_lf_group@blacksheep.org
In-Reply-To: <BFEF51489E054DE9ACE6501028FA73AD@lindavideo>
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Subject: Re: AW: LF: Influence of a TX antenna to a small rx antenna
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Hi Ken. I dont know but I would think it should be minimal. The "suckout=
 effect" does seem to be most pronounced with tuned aerials. I likened it=
 to a GDO effect where a passive tuned circuit absorbs power from an oscil=
lator. Roelof's mini-whip not being tuned and being a fairly small couplin=
g capacitance, and so would probably not show the effect. The effect is mo=
st noticable on receiving loops where a tuned T can totally destroy the pa=
ttern of a loop and also injects wideband noise into it. However detuing=
 the "T" removes the great majority of the problem. I have a dramatic demo=
 of the coupling when I got a high induced voltage from a nearby lightning=
 srtike which jumped from the isolated wire end to a earthy point. My indo=
or tuned loop was "inside" the inverted "L" profile and the voltage transf=
ered to the 16t loop blew the gate out of a 2N3819 I use as and impedance=
 converter. I draw the wire out of the house on nearby storms now !! =20

Roelof's mini-whip is certainly a very useful addtion to the LF receiving=
 armoury..... though it is not as simple to use as we might expect.....as=
 shown by some of the recent messages.=20

Best Wishes for DX in 2010
Alan G3NYK  =20

--- On Sun, 27/12/09, Ken <ken.h.wright@btinternet.com> wrote:

> From: Ken <ken.h.wright@btinternet.com>
> Subject: Re: AW: LF: Influence of a TX antenna to a small rx antenna
> To: rsgb_lf_group@blacksheep.org
> Date: Sunday, 27 December, 2009, 12:20
> Hello Alan.
> A very interesting paper of yours, is it likely that there
> will be the same=20
> interaction between a T antenna and the PA0RDT Mini Whip?
>=20
> 73.
> Ken
> M0KHW
>=20
>=20
> ----- Original Message -----=20
> From: "ALAN MELIA" <alan.melia@btinternet.com>
> To: <rsgb_lf_group@blacksheep.org>
> Sent: Sunday, December 27, 2009 11:51 AM
> Subject: Re: AW: LF: Influence of a TX antenna to a small
> rx antenna
>=20
>=20
> Hi Stefan I hope it does not give you indigestion :-))
>=20
> Good luck with it.....all LF sites are different so in
> general require=20
> different detailed solutions. It seemed generally to be
> sufficient to=20
> de-tune the unused antenna to reduce the interaction to low
> levels.
>=20
> Best Wishes for Dx in the New Year
> Alan G3NYK
>=20
> --- On Sun, 27/12/09, Stefan Sch=C3=A4fer <schaefer@hst.tu-darmstadt.de>
> wrote:
>=20
> > From: Stefan Sch=C3=A4fer <schaefer@hst.tu-darmstadt.de>
> > Subject: AW: LF: Influence of a TX antenna to a small
> rx antenna
> > To: rsgb_lf_group@blacksheep.org
> > Date: Sunday, 27 December, 2009, 10:55
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > Hi
> > Alan, tnx, i have
> > printed your article and will read it now at
> breakfast
> > ;-)
> >
> >
> >
> > Perhaps
> > I will come back
> > with some questions=E2=80=A6 J
> >
> >
> >
> > 73,
> > Stefan/DK7FC
> >
> > -----Urspr=C3=BCngliche
> > Nachricht-----
> >
> > Von:
> > owner-rsgb_lf_group@blacksheep.org
> > [mailto:owner-rsgb_lf_group@blacksheep.org]
> Im Auftrag von ALAN
> > MELIA
> >
> > Gesendet:
> > Sonntag, 27. Dezember
> > 2009 01:32
> >
> > An:
> > rsgb_lf_group@blacksheep.org
> >
> > Betreff: Re:
> > LF: Influence of a TX
> > antenna to a small rx antenna
> >
> >
> >
> >
> >
> >
> >
> >
> >   Hi Stephan yes the aerialls will
> > be very close
> >   compared with the wavelength so they
> will interact
> > particularly is tuned. We
> >   did some measurements ar Finbar's
> location several
> > years ago
> >
> >   http://www.alan.melia.btinternet.co.uk/aecouple.htm
> >
> >
> >
> >   The interaction was measured on an
> antenna  RF
> > bridge, and demonstrates
> >   the coupling between two wires.
> >
> >
> >
> >   Best Wishes
> >
> >   Alan G3NYK
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
>=20
>=20
>=20
>=20