Radio Crystals Developed during War

Here’s a very cool post on the development of radio-crystal manufacturing during the Second World War. Xtals had been used experimentally before the war, but the need for reliable communication transformed amateur radio based mostly on coil and capacitor oscillators to the widespread use of much-more stable crystal ones.





At our local club’s annual swap meet in September, the technology of all but the first few decades of amateur radio was on display. Vacuum tubes, transmitting coils, high-voltage variable capacitors, quartz crystals, and “boat-anchor” rigs from the 1950s were juxtaposed with software-defined radios, with everything in between in various hybrid combinations. But isn’t all that older stuff “obsolete”? Not on your grandfather’s spark gap!

Is the tuned LC “tank” circuit obsolete?

The thing is, all that earlier technology still works as well as it always has, except I suppose if you think that reducing VFO drift down to 1 ppm over 60 minutes is something you can’t live without. With good ol’ ovenized oscillators and other forms of thermal stabilization, I’m satisfied enough to get on the air without concern over some good, honest drift. If some Barney-Fife operator wants to complain my signal drifts 10Hz per hour, he can kiss my plate chokes, and he’d get what’s coming to him, too.

Not until the twentieth century did “obsolete” enter the everyday talk of ordinary people. Within the scope of what we all call “technology’—all dependent on electricity–change has come at a dizzying pace. In some cases, new developments result in real value added to the human condition, while others only serve to foster dissatisfaction and discontent. And always there’s something else to buy. I’m as fond of technology as the next radio amateur, but I’m more fond of contentment and peace of mind, especially when the proffered advances seem—to me at least—less than compelling.

In gaining some insight into this march into perpetual obsolescence, it’s worthwhile to look at other technologies that have survived the onslaught of the “new and improved.” Painting did not disappear upon the introduction of photography in the middle of the nineteenth century. It’s still alive and well in the art world, and materials for it are available, even at “big-box” superstores. Though typewriters have been mostly supplanted by desk- or laptop computers, pen, pencil, and paper have not. Synthetic textiles are superior (easier to maintain) in most respects to those made of cotton or wool, but natural fibers used before recorded history are still very-much in use. And so on.

Likewise, the technology of the codex ( was a true advance over the book scroll since a scroll can be accessed only in a fixed sequence, while any page of a codex can be accessed immediately. A synoptic skimming of a codex is no more difficult than flipping through its pages. Not so with a scroll. Well, though our tablets and notebook computers are right up to date, we’re now back to scrolling. Not everything new is unassailably better.

I admit this may be much ‘ado about nothing, and in fact it may be only slightly more meaningful than any other garden-variety navel-gazing and pseudo-intellectual self indulgence. But the old boat anchors and hollow-state gear is still around, the coils and capacitors are still used by some to create tuned circuits, and it can all live side-by-side in anyone’s radio shack. It does in mine. It’s one of the “cool” things about Ham Radio.