Return to KLUBNL.PL main page

rsgb_lf_group
[Top] [All Lists]

Re: LF: VK1OD's analysis of the MiniWhip antenna

To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: VK1OD's analysis of the MiniWhip antenna
From: pat <g4gvw@aol.com>
Date: Thu, 04 Jul 2013 13:36:54 +0100
Authentication-results: mx.google.com; spf=neutral (google.com: 195.171.43.25 is neither permitted nor denied by best guess record for domain of owner-rsgb_lf_group@blacksheep.org) smtp.mail=owner-rsgb_lf_group@blacksheep.org; dkim=neutral (bad format) header.i=@mx.aol.com
Cc: Graham <g8fzk@g8fzk.fsnet.co.uk>
Delivered-to: daveyxm@virginmedia.com
Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mx.aol.com; s=20121107; t=1372941416; bh=cigjgbDqE9yOQrEyimVpIGtjoushvIYFtceGZNKETgk=; h=From:To:Subject:Message-ID:Date:MIME-Version:Content-Type; b=jB8xknYFeAK/PzkCEk4j9DZf7VaW8jRSihbFruo19CGqhlrpniIBbiD8Uy/LVjK56 aTBcHzUVzb6XOley4BZFveEtgt69cqa9Aeu/XYJcpQmshcfeQCjSG6Q4VMm2gVUvaj wfHUW+KXVOIOC15HA0bap3Lvcr+NUr2wtXldxarg=
In-reply-to: <A8862096D2BB4263B99E98231765D039@AGB>
Organization: G4GVW
References: <CAKvcm2dpuftdtK6OdQv8fOfiw+4yQrPBQBHJ-FN2gDbT4P_oMQ@mail.gmail.com> <51D498BD.3050007@iup.uni-heidelberg.de> <A8862096D2BB4263B99E98231765D039@AGB>
Reply-to: rsgb_lf_group@blacksheep.org
Sender: owner-rsgb_lf_group@blacksheep.org
User-agent: Mozilla/5.0 (X11; Linux i686; rv:17.0) Gecko/20130623 Thunderbird/17.0.7
Isn't it also true that for any given signal and noise field there will be an optimum antenna positioning and orientation that will achieve the best obtainable s/n. There is, likewise. an antenna configuration that will produce an optimum result. This probably says that the optimum situation is found by experimentation and "rules" may always have their exceptions.
73


On 04/07/13 12:32, Graham wrote:
G2AVJ* asserted that Maxwell had slightly over cooked things and there where no E and H fields , only vector potentials , may be the mini-probe is a near field array , as its certainly not big enough for any other concept ?
As  for  big Ae's  .that's  really   only  down  to  location, in open 
space  , then  a  1 mile  wire Ae will  produce  some  very low  s/n 
levels  , in a urban setting , nothing  but  volts  of noise , its 
true  a small  probe  can be  located  in a low noise position , but 
this  is  the geometry  of the  noise distribution  , not the  Ae  itself
73 -G..


* Silent Key now

--------------------------------------------------
From: "Stefan Schäfer" <Stefan.Schaefer@iup.uni-heidelberg.de>
Sent: Wednesday, July 03, 2013 10:33 PM
To: <rsgb_lf_group@blacksheep.org>
Subject: Re: LF: VK1OD's analysis of the MiniWhip antenna

Wow, thanks.
This can lead to a lively discussion :-)

I think there are some misunderstandings by VK1OD. He states that Roelof says that: "noise is mainly magnetic". But Roelof means the local noise and not the far field noise, e.g. from thunderstorms. That is the difference! The local noise H fields pass the walls rather than the E fields, in many constellations like urban areas. Furthermore there can be a significant advantage in the obtainable SNR compared to a "big" antenna because that small whip antenna can be lifted easily by several meters above ground, without having a high wind load. A big antenna with a feed point at ground level and a few meters near the house may catch a lot of local noise.
For me, here on the institutes roof, the small whip antenna 
(https://dl.dropboxusercontent.com/u/19882028/MF/LFMFprobe.JPG) 
achieved MUCH better results than the 70m long wire 
(https://dl.dropboxusercontent.com/u/19882028/LF/IUP%20Antenne_resize.jpg)...
73, Stefan/DK7FC

Am 03.07.2013 01:02, schrieb Dimitrios Tsifakis:
Hello group,

here is a web page written by Owen, VK1OD with an analysis of how
PA0RDT's Miniwhip antenna works:

http://vk1od.net/antenna/PA0RDT-MiniWhip/index.htm

You may find this interesting.

73, Dimitris VK1SV


--
73 de pat g4gvw
es gd dx
qth nr Felixstowe
East Coast UK



<Prev in Thread] Current Thread [Next in Thread>