Tuesday, June 13, 2023

How they Make Raspberry Pi 4 Single Board Computers


So, if the Raspberry Pi is a key part of your new "homebrew" rig, how much of the rig did YOU actually build? 

3 comments:

  1. You've just stagnated ham radio. No ICs, no synthesizers and no CPUs. You're stuck with beginners pablum from fifty years ago. Your vision of ham radio is primitive, and no place to go up.

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  2. Well, for a more nuanced and playful response than Michael's rather uncharitable one (and because I think Bill is playing the provocateur), I would say: "How much did I build? That depends on how you measure it."

    If you go by weight, then an R.Pi would be no more than about five percent of the total. If it's a field rig with store-bought batteries, then an even smaller percentage.

    Now if you tried to determined "how much" by component count, then you'd have to first clearly define what you mean by "component." In the audio world, a "component" could be an entire tape deck, amplifier, for graphic equalizer. Is an LM386 a single component or is it a assembly of components? As with other ICs, it's only a single chip of silicon, but then so is a 2N3904. A vacuum pentode may be used as a discrete component, but the glass ones seem clearly like assemblies of plates, filaments, and screen wires. A 12AU7 (of guitar-amp fame) is an assembly of two triodes. A 6AU8 has both a triode and a pentode in it. Given the number of plates, filaments, and screens involved, it's actually a wonder of *integration* in such a small tube. So, because of the problems associated with defining "component," I don't think counting them would result in a "how much" answer.

    But if "how much" is to consider the intelligence and knowledge required to build a rig, then clearly the Pi version requires significantly more than the tried-and-true analog methods of producing stable VFO/BFO signals. That's at least the complaint by many who say that digital methods require too much arcane, abstruse, obscure, and specialized knowledge to be used comfortably. Of course, employing the power of an R.Pi merely for VFO generation would be gross overkill, but if it's to be used in a homebrewed SDR rig then the intelligence and knowledge content can reach heights not generally attainable by analog methods, and every bit of it requires careful attention on the part of the homebrewer. This is partly true because, unlike analog methodologies, there are no fudge factors or approximations to get one by. The software and electronic connections are either correct in every respect, or the thing doesn't work at all. This requires much more in the way of attention and *intention* than most analog methods, and it requires the homebrewer to put more of him or herself into the rig than otherwise. It's not for the faint of heart.

    Maybe another way of exploring this issue would be to visualize two piles of stuff on the workbench. One pile contains transistors, diodes, inductors, capacitors, resistors, and wire, while the other contains some transistors, diodes, inductors, capacitors, resistors, wire, and a RaspberryPi. What are those two piles now? Nothing. They're nothing at all except uncoordinated, unassociated, unconnected, and otherwise useless things. Now imagine each of those piles transformed into separate working rigs. They were nothing before but now they're something.

    What happened? Homebrewing happened. "Let there be RF," the semi-divine home builder said. And there was RF.

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  3. Super video. An example of factory re-purposing which kept people working. The robotics are a necessary part of the process, you couldn't get people to do the tedium, and still keep the costs low enough for us consumers.
    So to Bill's point, maybe with that Raspberry Pi, you wrote your own programs, and interfaced it with your hardware. You may have designed/build your RF and audio. It's a building block that makes it easy for others to duplicate your work. And its really neat when others build and refine your design to meet their needs.

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