[TowerTalk] RF Ground is not a Myth

[Patrick Greenlee]

Holy Cow!!!   Welcome to Lilliput.   Didn't a lot of us start out with 
the water analogy to understand simple electrical circuits.  In my first 
formal electronics studies we used hypothetical components: pure 
resistances, perfectly conducting wires, idealized capacitors and 
inductors and then later had radiators over perfectly conducting planes 
of infinite dimension.  Different levels of detail and "reality" are 
appropriate for different purposes.

So someone treats a simple wall switch as an on off device and someone 
else has to complain because he didn't allow for its inductance, 
capacitance, radiated energy, damped oscillation from the little arcing, 
and on and on.  Sometimes a switch can be just an idealized on off 
device with little consequence with respect to the actions of the device 
that switch energized.

Which end of the boiled egg do you break open, i.e. who do you support 
in this war of the Lilliputians?   Quoting Rodney King, "Can't we all 
just get along?"  We don't have to agree with one another to be civil. 
I, for one, learn from the interchange of ideas and technical challenges 
we pose to each other but lets keep it above the level of a street 
fight, OK?

Patrick    NJ5G

On 1/23/2015 5:20 PM, Steve Maki wrote:
> I was flabbergasted at the response to Duffy's post, which seemed 
> relatively non controversial to this relatively low level scientific 
> brain of mine. Can't one specify a perfect ground (even though 
> impossible in the real world) when modeling antennas? Is that not a 
> useful exercise as an educational tool? Does that not prove his point?
>
> -Steve K8LX
>
> On 1/23/2015 4:32 PM, Wes Attaway (N5WA) wrote:
>
>> "Believing in something does not make it so" .... Really?
>>
>> What about an isotropic radiator, defined as a theoretical point 
>> source, as
>> used in every antenna modeling program?
>>
>> What about the "imaginary numbers" which consistently pop up in 
>> mathematical
>> analyses?
>>
>> The author (Bryan Fields) was careful to point why the use of 
>> something that
>> is not physically realizable is still useful (even required) in certain
>> kinds of analyses.
>>
>> I think he made a perfectly valid argument about why the concept of 
>> an RF
>> Ground is important, as he says "in understanding current flow in RF
>> circuits".
>>
>>
>>     -------------------
>> Wes Attaway (N5WA)
>> (318) 393-3289 - Shreveport, LA
>> Computer/Cellphone Forensics
>> EnCase Certified Examiner
>>     -------------------
>> -----Original Message-----
>> From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf 
>> Of Bryan
>> Fields
>> Sent: Thursday, January 22, 2015 11:52 PM
>> To: towertalk at contesting.com
>> Subject: Re: [TowerTalk] RF Ground is not a Myth
>>
>> On 1/19/15, 9:29 PM, James Duffey wrote:
>>> The RF ground is a useful theoretical construct. This theoretical
>> construct
>>> is a result of solid thinking.
>>
>> Believing in something does not make it so.
>>
>>> Given that it is hard to realize in
>>> practice, but it does have its use in understanding current flow in RF
>>> circuits, the practical problems in implementing a useful ground, 
>>> and why
>>> we have problems in circuits that we don't think should have problems.
>>> Simply put, an RF ground is an infinite source or sink of carriers,
>>> delivered or received with minimal delay. That of course is not
>> realizable,
>>> but understanding why the carriers cannot be delivered or absorbed with
>>> minimal delay helps a great deal in understanding the practical
>>> implementation of circuits we design.
>>
>> Literally nothing is correct in that paragraph.
>>
>
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