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Date: Thu, 12 Jul 2001 09:41:34
To: rsgb_lf_group@blacksheep.org
From: "Rik Strobbe" <rik.strobbe@fys.kuleuven.ac.be>
Subject: Re: LF: LF/Hyper test
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At 09:02 12/07/01 +0100, DJ2LF wrote:
>Some weeks before Markus DF6NM and me made some tests and found a max.
audible 
>distance of 1500m and a max. visible distance of 2500m (on screen of
laptop). 
>Rec. antenna was 10m vertikal.

Hello Walter,

congrats on the 9kHz crossband QSO.

Did you measure the current you could get into the antenna ? Ground-loss
must be extreme at these frequencies.

It is interesting to note that the signal seems to be audible up to 1.5km
and visible on screen up to 2.5km. If good software (argo, spectogram
etc..) was used this would mean that the signal level decreased about 20dB
between 1.5 and 2.5km !
Or otherwise it would mean that you would have to increase power from 12W
to 1.2kW to get an audible signal at 2.5km.
I tried a simulation with GNDWAVE3 and came up with only 4.4dB decrease
(but I haven't the slightest idea wether GNDWAVE3 is accurate at 9kHz and
1.5km).
Probably the communication on 33km was via some kind of (heavily absorbed)
'induced field'.

73, Rik  ON7YD