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: w...@w8ji.com > To: topband@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 _________________ Topband Reflector