Message-ID: <000d01ca7373$e4baa170$0401a8c0@xphd97xgq27nyf>
From: "mal hamilton" <g3kevmal@talktalk.net>
To: <rsgb_lf_group@blacksheep.org>
References: <38A51B74B884D74083D7950AD0DD85E828AAF4@File-Server-HST.hst.e-technik.tu-darmstadt.de> <4B16987B.9000002@usa.net>
Date: Wed, 2 Dec 2009 17:21:32 -0000
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Subject: Re: LF: Results of optimising an active antenna
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Use an aluminium beer keg as the probe mounted a few metres above ground.
g3kev

----- Original Message -----
From: "Alberto di Bene" <dibene@usa.net>
To: <rsgb_lf_group@blacksheep.org>
Sent: Wednesday, December 02, 2009 4:40 PM
Subject: Re: LF: Results of optimising an active antenna


Stefan Schäfer wrote:
>
> My Conclusion: It seems that a short receiving antenna can bee seen as a
> capacitive divider out of the capacity between far field and antenna and
> the capacity between antenna and ground. If the wire length is to much,
> the input stage becomes nonlinear/goes into saturation. If the height
> above ground is increased the signal comes up, but not the signal/noise
> ratio(surely there will be a benefit if such an antenna is placed in a
> region with heavy local qrm. Then, the height should be increased and
> the wire length can be decreased). So, one cannot say “the more the
> better” talking about the wire length!

It would be quite interesting if somebody could try to use, instead of a
wire, something
with a greater capacity towards ground, e.g. a can of beer (after drinking
the beer, of course...:-)
One of half liter (slightly more than 1 pint) could do, I think...

Maybe the increased capacity towards ground could make it more effective
than a wire

73  Alberto  I2PHD

P.S. And the entire active antenna circuitry could be placed inside the
can...