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Date: Thu, 04 Jul 2013 16:40:43 +0100
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CC: Roelof Bakker <roelof@ndb.demon.nl>
References: <CAKvcm2dpuftdtK6OdQv8fOfiw+4yQrPBQBHJ-FN2gDbT4P_oMQ@mail.gmail.com> <51D498BD.3050007@iup.uni-heidelberg.de> <op.wzo6og2lyzqh0k@pc-roelof>
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 Content preview:  Roelof, I remember reading about a very similar antenna arrangement
    early in my career. It was described by the writer (name forgotten) as "one
    plate of a capacitor - the other plate being the rest of the universe". Somehow
    that description has stuck in my mind and has served to provide a simple
   explanation of "small" antennas in general. [...] 
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Subject: Re: LF: VK1OD's analysis of the MiniWhip antenna
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Roelof,

I remember reading about a very similar antenna arrangement early in my 
career. It was described by the writer (name forgotten) as "one plate of 
a capacitor - the other plate being the rest of the universe". Somehow 
that description has stuck in my mind and has served to provide a simple 
explanation of "small" antennas in general.

73


On 04/07/13 13:37, Roelof Bakker wrote:
> Hello Stefan,
>
> I have been reading VK1OD's article with great interest.
> It is a pity that he has not discussed the antenna with yours truly.
> This should have avoided a number of inaccuracies.
>
> I have had quite a few email exchanges with a number of experts.
> Some state that the antenna can't work, others said that it works, but 
> that I did not understand how it works.
> Which was true!
>
> The antenna has evolved completely by experimental work with the goal 
> to find an antenna that will work on LF and features immunity to in 
> house local noise. Which goal has been achieved.
>
> To understand how it works requires a bit of up side down thinking 
> (literally!)
> The antenna emulates a monopole, however what we consider to be the 
> antenna element, it is not.
>
> This applies also to the classic active whip, at least on LW and MW.
> In fact, the antenna element should be considered as an artificial 
> ground and that is the reason that e.g. a 1 meter long whip can be 
> replaced by a piece of copper clad PCB with about the same capacitance.
>
> There is no question that this concept works. I received NDB IPA-280 
> from Easter Island in the Pacific on it.
> And no weak trace screen watching whatsoever, but aural copy of the ID 
> in morse code.
>
> It should be nice if all members of the amateur community were well 
> off and could afford unlimited real estate.
> In that case we all should be using beverage farms for reception and 
> spending a bit more time in the great outdoors to keep things up and 
> running.
>
> However the vast majority will have to cope with limited resources, 
> being lack of real estate, lack of finances or both. This is where a 
> bit of ingenuity comes into play and the fun starts.
>
> It is truly amazing what ideas have been put to work to overcome 
> unsurmountable limitations. One excellent example is the ongoing 
> development of weak signal software, which has made LF work possible 
> for many more people than just the happy few!
>
> Best regards,
> Roelof Bakker, pa0rdt
>