[TowerTalk] Dream on,he will have to prove it to manufacturers on his de...

[i4jmy@iol.it]

Antenna modeling, at least to determine maximal gain (phisical of the 
array) is more accurate than any test environment.
A test environment is a useful tool when all the external parameters 
are under control and/or some antenna "feature" is unknown (read trap 
losses) and one knows how to read what's actually measured.
The basical limitation with modeling is the approximation of real 
devices and the unavoidable simplification of the external evironment.
The test field limits, expecially when performed out of an anechoical 
chamber, are the existing and uncontrollable parameters (ground wave, 
side modes of propagation, reflections,  etc.) or the impossibility to 
warrant short and long term calibrations (instruments) or to measure a 
resultant pattern (of direct wave and ground reflections).
Moreover, comparing HF lobes at angles (generally zero elevation) where 
the lobe attenuation is already noticeable (to minimize reality) and 
unwawnted modes or reflections are dominant, we may easily get false 
results.
Using an accurate antenna modeling in a free space situation we can 
know for sure what's the maximum gain obtainable by any antenna array 
and we can compare antennas in a theoretical (but real) plain field.
Unfortunately that gain will be hardly obtained in practice and nothing 
beyond real is actually true.



73,
Mauri I4JMY


> ---------- Initial message -----------
> 
> From    : owner-towertalk@contesting.com
> To      : towertalk@contesting.com
> Cc      : 
> Date    : Sun, 11 Feb 2001 22:51:35 EST
> Subject : Re: [TowerTalk] Dream on, he will have to prove it to 
manufacturers on his de...
> 
> In a message dated 2/11/2001 22:29:20 Eastern Standard Time, 
W4EF@dellroy.com 
> writes:
> 
> > 
> >  BTW, are you planning to publish the range data with all the 
details of 
> your 
> > scaled tests at
> >  2 meters (range description, reference antenna, gain, F/B, VSWR, 
etc). 
> That 
> > would go a lot further 
> >  to proving your case than all the heated rhetoric that has been 
floating 
> > around here the last few 
> >  days. 
> >  
> >  73 de Mike, W4EF...............................
> >  
> 
> I agree on your point about the software, it is wonderfull tool, but 
has to 
> be used wisely and results checked out, especially in the "weird" 
> configurations and close to ground. I am just in the process of 
mastering 
> EZNEC, trying to come up with arrays for the beach, so I can use them 
in the 
> upcoming contests. I will model Razors and see if they "work" on 
paper too :-)
> The rest will depend on what I will decide to do with them. But the 
more 
> detailed Razor story will be coming up, most likely in one of the 
magazines.
> Thanks you for your comments and support.
> I will have to shorten my lurking on reflectors, I keep typing 
arguments, 
> while work is not getting done.
> 
> Yuri
> 
> --


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