Amateur radio is one of my hobbies and I want to keep it that. It has held a major place in my sphere of activities for a good many years but, like radio itself, the firmness with which it grips me and orders me around is a variable, and even oscillating, quantity. It has never made me its slave, at least for very long, and then only because I didn't know any better. I do confess to having gone through and survived certain periods where little else but "wireless" entered my mind. When in such a trance, I was often guilty of sneaking an Electro Importing Company catalog into church and being carried glamorously away to pinnacles of imagination by its oily language, irresistible arguments and convincing illustrations contained in that now-famous yellow-covered "bible."
Why a coherer cohered and what it cohered seemed easy enough to understand. What the man said about detectors seemed plausible. But I never really believed in that one-hundred-mile transformer coil, especially after seeing one. I distinctly remember frowning upon telephone receivers wound with German Silver wire in order that they might bear the magic legend "3000 ohms" because I knew, from certain experiences with toy motors, that resistance itself was not what made them work.
The Call of Science
Then came a period of serious study. Robison's Manual displaced the old catalogs and a firm idea of decrement (now a seldom-heard word) planted itself—so firm, indeed, that when, some years later, a professor asked me to define logarithmic decrement, I almost answered "two tenths maximum!" At that time, I tried to believe that wireless was an exact science and that if I were to get anywhere, I would have to become an exact sciencee. There were some drawbacks to this. The ultimate explanation of a lot of things soon bogged me down in the mire of mathematics, which, at that time, was largely something to be "passed" in school. I came to earth again when I realized that I could and did communicate with another amateur across town without the aid of any mathematics of importance. I didn't realize that a thing could be obeying perfectly definite physical laws even though the laws were not thoroughly understood, or were, perchance, even unknown. It seemed unnecessary to think very much about the ultimate explanation of the goings-on so long as a certain feel concerning the thing was had. This state of mind made wireless a pleasure to me, with always the thought in the background that the mysteries would ultimately dissolve, to be pleasantly replaced by deeper ones. In the meantime, I wouldn't worry too much about them.
Vectors and Things
So, up to this time, mathematics did not seriously enter the picture. I had a good understanding of resonance phenomena, thanks to certain analogies, but my understanding was not a mathematical one. I had never heard of a vector diagram. It just seemed the most natural thing in the world for a circuit to respond more readily to some wavelengths than to others. Impedance and inductance? I didn't know exactly what these ponderous terms meant; I rather felt their import. I still do. Later study of alternating current phenomena and theory interpreted things in a different light. I still refused, nevertheless, to accept the mathematical as the only way of thinking. I now admit that there are some things which I can explain satisfactorily only with the aid of mathematics and with mathematics only. And plenty which I can't explain away, nohow!
As I progressed in the art, so the art itself progressed and, it seems, at a much faster rate. From time to time I found myself woefully behind the times. Technical papers began to appear on my horizon—papers which, to me, defied understanding. Once in a while, some brilliant and inspired author would come across with "the dope" with diagrams I could understand—little or no math—a clear word-picture of what went on—what to do in order to make it perk. To me, such information was vastly more important than cumbersome technical papers. I shamelessly admit to having perpetrated at least one paper which probably scared off a lot of hams from the realization that the thing would actually work.
The Ogres and Bogies
And so, in recent years I have built up a certain philosophy regarding this hobby of mine. It is my Aladdin's Lamp, carrying me to far-off countries (provided the Kennelly-Heaviside layer is right!), my servant to call with a snap of a switch. Why be deprived of the pleasure hidden in amateur radio by allowing its ogres and bogies to hold the whip hand? A hobby mustn't be taken too seriously. Mathematics has its place in the scheme of things, but it shouldn't be allowed to become the master of hobby. If a fellow wants to think in terms of mathematics when he winds a choke coil, let him. Maybe he likes to. After a while we get so that we just wind it and it works, although maybe not the first time. We know about how many turns of copper tuning are going to be required for a given job. Even the mathematician gets that way sooner or later. Witness his solution of differential equations; what does he do? Why, he writes down the equation and takes a good look at it. He then says to himself, "It strikes me that the solution to this equation should be so-and-so." So he boldly writes down a good looking solution. Does he solve for it? He does not. He stifles any qualms he may have and justifies his rash act by putting in a proviso. He says, "So and so is a solution provided such-and-such is the case." Simple, isn't it?
Let's Make a Tank Coil
This is just the kind of thing I do when I want to make a tank coil hit the forty-meter band. Oh, I don't pretend to go to the mat with some formula born in the Bureau of Standards having to do with the inductance of solenoids. I just take down the old roll of copper tubing, reel off a goodly length and wind it around the now well-polished piece of iron pipe. When I think I have enough turns—my solution to the problem or equation—I cut the rest of the tubing off and finish up the mechanical details. Can this be the right number of turns? It is the right number of turns provided I use the right capacity in my tank condenser. Here is my proviso. Of course, experience is necessary. To get experience in this little matter, just wind a few coils for certain particular jobs. It is something you can't help acquiring unless you are a third-degree moron.
Or an Antenna
Another class of, it seems to me, misled hams are those who are hidebound in their notions concerning physical details. Some of these fellows are prone to measure the length of their antenna to the fraction of an inch. Why do they do it? Probably because someone told them it was the thing to do or because they are using trick antenna and feeder arrangements for one reason or another. Some folks just like to make things complicated. I've always felt that complexity bore rather directly on possible trouble. In the case of my own antenna, don't ask me its exact length. I don't know it to the nearest five feet. Furthermore, I don't even care. The oscillations on a radiating antenna being of the standing wave variety, there will be a nodal point about a quarter-wave away from the remote end. It can't be anywhere else for that frequency. It only remains to choose and use the proper type of coupling between the antenna and transmitter to make the current at this point (or any other fixed point, for that matter) have a reasonable value. When the rig is tuned properly and the various circuits are functioning as they should, I know it. Not by exact instruments (though I admit that a plate milliammeter is handy) but largely by the feel of the thing. Probably a lot of factors enter into this; the grunt of the homemade plate transformer, the color or lack of it in the plates of the tubes, sparking at the keying relay and other equally silly and dizzy things. Even with multi-stage crystal transmitters, I decline to make a hard job of it. A flock of plate milliammeters shows, among other things, how unstable radio circuits can be. They are therefore useful in detecting faulty design and crumby workmanship. But then again a neon tube and a flashlight bulb inserted in a single turn of wire will work wonders in lining up a set, once the frequency is determined.
Speaking of frequency, a precision frequency-meter is a thing of beauty and a joy to use, providing the degree of accuracy is known. We are exhorted to keep checking its calibration, lest something shift on us unbeknownst. Personally, I haven't such a thing, never having felt the urge to flirt dangerously with the edge of a band. A calibrated receiver, with easily-made and frequent checks, serves for all practical purposes and has thus far steered my signals in the paths of righteousness. (If I have occasionally emitted signals outside the bands assigned to amateurs, I believe the errors were gross ones, such as catching the third harmonic of an amplifier instead of the second, as intended.)
Slave or Master?
And so it goes. When I become a slave to radio theory, then radio will cease to be the hobby that it has been and is. I am willing to accept (with reservations) the results of the seriously-minded experts in the laboratories. Let the experts worry over such matters as exactly 100% modulation. It doesn't mean anything important to me because literally, it is a theoretical panacea only to be obtained with carefully-controlled laboratory set-ups, precision sources of sound at exact distances from expensive mikes, jealous scrutiny applied to generally inaccurate meters, faith in the published theory and in the constancy of tubes. I object to it because if the ham talks in anything other than an electrically driven tuning-fork voice, shifts his position or even acts naturally, he either has less than 100% modulation or—horrible thought—that bogey, distortion. Personally, I can't be bothered.
|R. B. Bourne. W1ANA||from QST, July 1932, pages 13–15 and 18|