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Frank Gilliland ) writes:
Let me ask you a simple question: Suppose someone buys an SP-600, mounts some chrome knobs, spray-paints his name on the front panel, then posts on the newsgroup saying, "Hey, look what I built!" Would you call that "homebrew"? I think there's a vast difference between that scenario, and building with ICs. In your example, they are mere cosmetic work. But when building with an IC, you will have to actually build something around it in order to get something useful. I am a bit surprised that you hold this opinion this late in the game. Clearly, it was not an uncommon opinon thirty or so years ago, when people would write to the magazines and complain about so many ICs being used, and about how the internal diagram of the IC was not shown. A lot of that could be discounted as a transitional reaction, that since ICs were new people were reacting to the newness rather than an absolute reaction to ICs being "cheating". At least thirty years on, it's hard to imagine that there are people who haven't adapted. As others have pointed out, one can go down through a spiral to an absolute level of "homebrew", but everything would be pretty bulky then. Of course, early hams built their capacitors and all that, but it was more necessity than some hard core belief. Once you could get commercially available components, then they were used unless a) someone was curious about making a capacitor or b) what was exactly needed wasn't available. There are some borderline parts. It hardly makes sense to buy a commercially made coil if you can wind one yourself, but that's not because everyone should be making everything, but because if someone isn't winding, they may not realize it is a simple thing, and winding will save money. What ICs have done is allow for a level of complexity that wasn't available before them. Sure, there were PLLs described in the ham magazines using tubes, but they were as complicated as a simple superhet receiver. I can remember seeing tube based synthesizers, using multiple crystals mixed together, and they were more complicated than a full blown transmitter. If you want to build up a whole synthesizer from transistors, it's going to be terribly bulky. I suspect few will go to that trouble, and instead making something simple but which won't give the performance of a synthesizer. There is so much that can be built nowadays that virtually nobody would consider building in the tube era. So I dismiss your hardcore view on this. On the other hand, there is validty in constantly thinking through whether something should be done with transistors or ICs. One shouldn't build with ICs for the sake of building with them; if two transistors out of a scrap VCR and some other components from it flash an LED perfectly well, then what's the point of using an expensive and hard to get IC that exists only to flash LEDs? If you don't lose anything in performance, and only a little space, then you might as well use readily available scrap transistors to build an IF strip, than spend money and time buying an IC via mail order. If two transistors will supply a suitable prescaler for Harry's project, then it likely is a good choice, because it's easier to find transistors than prescaler ICs. But these are design decisions, not some rhetoric about how everything must be made from scratch. Any time something is designed, it's important not just to look at the way to do it, but at other alternatives, because people often do get blocked by looking down only one path. For instance, as I write this it occured to me that it might be easier for Harry to mix the VCO signal down to a frequency where the average logic IC can work. You don't have to find a prescaler, and the design's frequency steps won't be limited by the division of that prescaler. There are various mixer schemes that will result in the needed frequency. There may be reasons for not doing it this way, but it may not even be explored because Harry hasn't given this alternative any thought. Michael VE2BVW |
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