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 lengths,
and stations causing the problem are close to hand. You need a significant
induced current (hence the need for near resonance) to radiate a strong enough
signal from an inefficient mixer like that.
It is obviously a contender but I tend to question anyone who may be
"extrapolating 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) running 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 transmitter
site so are generally head over a wider area independent of direction.
Best Wishes
Alan G3NYK
--- On Mon, 7/12/09, Jacek Lipkowski <[email protected]> wrote:
> From: Jacek Lipkowski <[email protected]>
> Subject: Re: LF: Broadcast audio splatter on 136kHz
> To: [email protected]
> Date: Monday, 7 December, 2009, 21:09
> On Mon, 7 Dec 2009, Paul-Henrik
> wrote:
>
> > [...] Luxembourg effect, transmitter IMD or just me
> missing the point?
>
> 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?
>
> jacek
>
>
>
>
>
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