Topband: Elevated Radials

[john battin]

This reminds me of an experience I had with a new antenna.  After working several days installing a new antenna, I attached it to an a/b switch to compare it with my old antenna. I was delighted, the new antenna was always better !!!  Then to my dismay I saw I had the switrch reversed ... oh boy... I changed the feeds, and continued the test.  Guess what.. the new antenna was still always better. 
Lesson learned .... human nature and switching antennas in face of QSB.
 
John K9DX 


> From: w8ji at w8ji.com
> To: topband at contesting.com
> Date: Wed, 6 Mar 2013 08:00:56 -0500
> Subject: Re: Topband: Elevated Radials
> 
> > I've noted your postings re elevated radials to replace deteriorated 
> > buried
> > radial fields under broadcast towers. I'm familiar with the work and the
> > results. This work, of course was done by professional broadcast engineers
> > with significant instrumentation at their disposal. Of course, they also 
> > had
> > to measure the field intensity in the far field and file it with the FCC.
> > Their work seemed to show that, once we have installed 4 elevated 1/4 wave
> > radials we're reaching the point of "diminishing returns" and that little 
> > is
> > to be gained by increasing the number of radials beyond 4.
> >
> 
> Charlie,
> 
> We shouldn't be critical of people. People believe what they want to 
> believe, including you and all of us. Here is how it really works:
> 
> 1.) In an FCC measurement, a test signal is sent and the SLOPE of 
> attenuation in the far field is used to estimate earth conductivity.
> 
> 2.) A graph (or formula, but generally a graph) based on the measured 
> attenuation slope is used to predict the expected signal at standard 
> distances.
> 
> This creates a problem, because if we look at measurements along a line in 
> any direction, they are often all over the place at various points. The 
> engineer has to smooth the readings out and match a curve, which gives the 
> engineer considerable lattitude depending on how he does the smoothing.
> 
> Even more important, ONE measurement system over one ground that contains 
> multiple old radials of unknown condition and one set of soil conditions 
> does not mean it applies to other conditions.
> 
> By far, the most accurate way to determine a change is to do a direct 
> measurement of what we want to know in an A-B comparison with only the 
> variable we are trying to define changed. This takes out the human emotional 
> factors and other errors, and then rememmber it applies to that case.
> 
> No matter how much we want something to be true, or how much we like or 
> agree with something, this is just how it **really** works. It's human 
> nature to gravitate toward a system that takes little room and installation 
> time, doesn't cost much, and is an "it always works this way" silver bullet.
> 
> We should not pick at people and call people names who point out obvious 
> flaws and limitations in faith-based conclusions. Anyone who has objectively 
> made measurements realizes there is no single universal answer, no matter 
> how nice it would be if there actually was one.
> 
> 73 Tom 
> 
> _________________
> Topband Reflector