Now rarely seen on television, the celebrity-chef Emeril Lagasse could once incite audience delight by declaring he was going to “kick it up a notch” by throwing a pinch of his trademark “Bam!” seasoning into the food he was preparing. While not clear just where these “notches” were, he was talking about an incremental improvement, a slight enhancement to what was certainly an already-tasty and nutritious dish.
Similarly, one often hears an athlete vow to “up his game” by implementing a series of small changes to his diet, workout routine, equipment, or skills practice. Some of these seem almost-laughably minor: an Olympic swimmer shaving his legs to minimize drag, runners wearing close-fitting clothing to reduce air resistance, and competitive bicyclists wearing Spandex for the same purpose. And so forth. How could such small changes be important enough to bother with? The short answer is that they’re not–by themselves–but cumulatively they are. They either add up or multiply to make meaningful improvement.
Spice in food and small changes in habits and methods are examples of what system analysts and statisticians call marginal gains. How they impact a system is related, in part (and paradoxically), to chaos theory: small changes can result in accumulating knock-on effects in a non-linear universe (such as the one we live in). Phenomena of this sort was first explored mathematically by Edward Lorenz in the 1950s in connection with weather modelling and prediction. In an older and more colloquial vein, the well-known cautionary nursery rhyme about a dispatch rider in a battle conveys a similar idea:
For want of a nail, the shoe was lost;
For want of the shoe, the horse was lost;
For want of the horse, the rider was lost;
For want of the rider, the battle was lost;
For want of the battle, the kingdom was lost;
And all from the want of a horseshoe nail.
And, of course, we all know at least one person whose life has become a total disaster after a concatenation and multiplication of seemingly-casual fuck-ups leading to still worse ones: lost jobs, bankruptcy, jail, and estranged families.
So how does all this relate to amateur-radio engineering? Another way of asking that is: can radio systems–transmitters and receivers–benefit from marginal gains? Certainly, and the better ones do. That’s one of the reasons why they’re better. For radio systems in mission-critical applications in aerospace and in the military, some of the gains are marginal indeed. Read a few Mil-Spec documents and you’ll find out just how minor some requirements are. You may say, “Sure, but that’s bloated, hundred-dollar-hammer stuff. The kind of pork-barrel excess paid for by deep government pockets. The rest of us get our hammers at Ace Hardware.” Okay, but as it turns out those who bet their lives on critical hardware don’t want any of it coming from the hardware store. They know how things can go sideways when small things are neglected. It’s only a slight exaggeration to say that such specifications were literally written in blood.
But aside from critical links in a chain (such as the horseshoe nail), there are also either improvements or detriments that can add up or detract from the end goal: the quality and reliability of the radio signal. To employ yet another metaphor, consider the effect of compound interest on the value of an investment. The gains aren’t linear, they’re exponential. The same is true of the effects of price inflation: higher costs drive costs still higher in an exponential spiral. For our amateur-radio technology, we want compound interest rather than inflation, don’t we?
This article is the first in a series of Up a Notch posts. Subsequent posts will be more concrete and less metaphorical. They will address the following and more:
- Use better components with tighter tolerances, lower temperature coefficients, higher Q, lower noise figures, and higher reliablility.
- Use better circuit topology with such measures as putting chokes on DC power and bias circuits, keeping resistors out of direct signal paths, using good DC decoupling, proper bias on active components to prevent overdriving subsequent component and circuit elements.
- Do a better job matching impedances. Not only does this improve the transfer of RF power, it also minimizes reflections that can lead to intermodulation distortions and reduced dynamic range. Some circuit elements–such as crystal ladder filters–are virtually unusable without proper matching.
- Add often-omitted system elements such as diplexers, power-supply filters, audio-tone adjustment, or active audio filters.
- Elaborate on already-included elements. For example, use a third-order filter instead of a second-order one, or add an additional stage of amplification to minimize noise generation from too-much gain in earlier stages).
- Shield against noise and interference. This can be overdone, of course, but it’s often dismissed entirely with “it seems to work fine without it.” Working “fine” is fine, but “better” is better.
Next post: Up a Notch: Use Better Components–Resistors
