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

[Michael Tope]

Hi Yuri,

Modeling has evolved to the point where it is an extremely useful tool for antenna design.
It was developed because physical iterations and measurements on real antennas are very 
time consuming and expensive. Accurate outdoor measurement without the aid of absorbing 
material can be tough if multipath isn't properly controlled. In a work project, I once measured
3.5dBi gain from a 1/2 wave dipole at 300 MHz. Is the theory (2.15 dBi) wrong? I doubt it - the 
measurements were made on an outdoor range. It was probably range problems or RF current
on the feedline (it was and end-fed vertical dipole) that caused the discrepancy. On the 
simulation side, I recently had an opportunity to range test a 240 GHz horn antenna designed 
on a computer by a colleague. The test results from the anechoic chamber were so close to the 
simulations that I am still rubbing my eyes (they matched down to about -40dBc). 

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...............................


----- Original Message ----- 
From: <K3BU@aol.com>
To: <towertalk@contesting.com>
Sent: Sunday, February 11, 2001 5:25 PM
Subject: Re: [TowerTalk] Dream on, he will have to prove it to manufacturers on his de...


> In a message dated 2/11/2001 17:44:43 Eastern Standard Time, poster@gate.net 
> writes:
> 
> > You can't just talk about it but will have to model it in a antenna
> >  program.
> >  
> 
> You can dreaming, while I am working :-)
> You still don't getit?
> The Razors were developed, tested and compared to commercial Yagis on 2m 
> antenna test range, which is much better, more controlled environment than 
> the HF bands and test sites. VHFers do have antenna measuring contests on 2m 
> and 70 cm, that's where the proof of the pudding is. Not some "calculations".
> If it is not modeled in an antenna program then it is no good! Wow!
> Live and learn eh? What's next, trying to solder the coax to the paper 
> antenna?
> I said I will subject them to antenna modeling programs, see if the programs 
> reflect the true real situation and how close.
> My, my what "technology" is doing to people. Two plus two is not four, if the 
> calculator doesn't say it?
> 
> For those from Rio Linda:
> Razors were developed on 2m models on real antenna test range. That's where 
> the gain figures and performance comparison was done, found to be major 
> improvement in antenna design, and worthwhile scaling and using on HF bands. 
> See the upcoming story, beautiful color pictures and explanation of the 
> process, so others can try to follow, if they wish.
> 
> 73 Yuri
> 
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