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Date: Tue, 15 Sep 2015 16:12:27 +0200
From: DK7FC <selberdenken@posteo.de>
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Subject: LF: Active E field antenna versus T antenna for LF/MF reception
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Status: O

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