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From: John Rabson <john.rabson07@gmail.com>
In-Reply-To: <e5cce049d6e5432e87f16f65481778c8@kabelmail.de>
Date: Fri, 18 Sep 2015 19:48:51 +0200
Cc: DK7FC <selberdenken@posteo.de>, uwe-jannsen@kabelmail.de
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References: <e5cce049d6e5432e87f16f65481778c8@kabelmail.de>
To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: Active E field antenna versus T antenna for LF/MF reception
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DJ8WX’s page referred to below is reported by my system to be an “attack page”. 

John F5VLF

> On 18 Sep 2015, at 19:00, uwe-jannsen@kabelmail.de wrote:
> 
> hi Stefan,
> pse see
> 
> http://dj8wx-dl.de/two.htm
> 
> 
> Uwe/dj8wx
> 
>  
> Von: DK7FC <selberdenken@posteo.de>
> Gesendet: 15.09.2015 16:17
> An: <rsgb_lf_group@blacksheep.org>
> Betreff: LF: Active E field antenna versus T antenna for LF/MF reception
>  
> Hi all,
> 
> Since a while i'm now comparing RX results between two omnidirrectional
> E field antennas. One of them is active (similar to the PA0RDT antenna),
> the other one is a T antenna, resonanted to the frequency of interest
> and matched to 50 Ohm... (So the T antenna could be used for
> transmitting). The small active antenna is inside a plastic tube, so
> (charged!) raindrops do not fall on the probe directly. The charge can
> flow to ground through the weak conducting water layer (probably in the
> range of 1E8 Ohm?).During rain i saw that the "QRN" was significantly
> higher on the T antenna.
> 
> So, could it be a better idea to use an active antenna (with a limited
> large signal capability and a non-perfect linearity!) instead of a
> "real" or "traditional" band-selective T antenna? Maybe worth to compare
> the results on a stereo RX ;-) I my imagination i see the active antenna
> with an umbrella to protect from rain (charged drops, |q| > 0). As
> higher the distance between probe and umbrella, the better the noise
> reduction and the lower the signal loss?
> Time to build and test the performance of an active E field probe
> consuming 5V/1mA...
> Just some thoughts...
> 
> 73, Stefan
>  

john.rabson07@gmail.com

Researching history of RABSON, BLACKSHAW, GAUNTLETT, VERLANDER and ROBSONNE