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Message-ID: <702134.97980.qm@web86505.mail.ird.yahoo.com>
Date: Tue, 8 Dec 2009 00:18:09 +0000 (GMT)
From: ALAN MELIA <alan.melia@btinternet.com>
To: rsgb_lf_group@blacksheep.org
In-Reply-To: <Pine.LNX.4.64.0912072152460.28819@paranoid.lipkowski.org>
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Subject: Re: LF: Broadcast audio splatter on 136kHz
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Hi Jacek, do you have experience of this effect at LF?? It is well known=
 at HF/VHF where it is more likely that metalwork will be near resonant le=
ngths, and stations causing the problem are close to hand. You need a sign=
ificant induced current (hence the need for near resonance) to radiate a=
 strong enough signal from an inefficient mixer like that.=20

It is obviously a contender but I tend to question anyone who may be "extr=
apolating HF ideas" into this part of the spectrum for practical examples,=
 because otherwise this is how the "urban myths" arise. After 15 years of=
 interest in LF I have never come across a case that I could be sure was=
 that particular cause but I do not live close to very high power stations=
.....I have BBC World service Orfordness is about 25 km away (1296kHz and=
 646kHz I believe) 250kW and I have a local MW BC station (1250ish) runnin=
g about 1kW about 2km away. The effects I have heard have aways come down=
 to ICM. and have never involved those local frequencies.

Markus DF6NM has done considerable investigation on similar things and in=
 general I think he finds the problems like this emanate from the transmit=
ter site so are generally head over a wider area independent of direction.

Best Wishes
Alan G3NYK

--- On Mon, 7/12/09, Jacek Lipkowski <sq5bpf@lipkowski.org> wrote:

> From: Jacek Lipkowski <sq5bpf@lipkowski.org>
> Subject: Re: LF: Broadcast audio splatter on 136kHz
> To: rsgb_lf_group@blacksheep.org
> Date: Monday, 7 December, 2009, 21:09
> On Mon, 7 Dec 2009, Paul-Henrik
> wrote:
>=20
> > [...] Luxembourg effect, transmitter IMD or just me
> missing the point?
>=20
> maybe just mixing by some rusty junction? (long rusty fence
> or something similar) does the imd vary when the weather is
> dry, and suddenly rain falls?
>=20
> jacek
>=20
>=20
>=20
>=20
>=20