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#1
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In , "Ian White, G3SEK"
wrote: Frank Gilliland wrote: My point was that the art of homebrewing loses something when it's reduced to just plugging in a chip. Seems like everyone is ignoring how the circuits work and taking the 'black-box' approach instead. [...] where's the fun in just hooking up power to a chip? That's not homebrewing, at least not in my book. Fair enough - only you can decide what you enjoy. When you post to the group, we know where you're coming from, so we can interpret accordingly. But only I can decide what I enjoy, only Harry what he enjoys, and so on for every individual. Amateur radio and electronics is about doing what each of us personally likes, not what we "should" or "must". You are entitled to your own opinions about other people's preferences, Frank, but it's disrespectful to post them here as personal criticisms (and it doesn't encourage the rest of us to respect you). 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"? -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
#2
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Frank Gilliland wrote:
You are entitled to your own opinions about other people's preferences, Frank, but it's disrespectful to post them here as personal criticisms (and it doesn't encourage the rest of us to respect you). 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 honestly don't share that compulsion to classify other people's projects as either "homebrew" or not. -- 73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB) Editor, 'The VHF/UHF DX Book' http://www.ifwtech.co.uk/g3sek |
#3
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Frank Gilliland wrote:
You are entitled to your own opinions about other people's preferences, Frank, but it's disrespectful to post them here as personal criticisms (and it doesn't encourage the rest of us to respect you). 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 honestly don't share that compulsion to classify other people's projects as either "homebrew" or not. -- 73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB) Editor, 'The VHF/UHF DX Book' http://www.ifwtech.co.uk/g3sek |
#4
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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 |
#5
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![]() "Michael Black" wrote in message ... But when building with an IC, you will have to actually build something around it in order to get something useful. SNIP 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". Over 30 years ago I homebrewed a PDP-8 work-alike computer. It was based on the PDP-8 instruction set. I've never seen PDP-8 electrical or detailed logic diagrams. I used ICs, but none more complex than a 4-bit adder. The 7400-series was then too expensive for me, so I used a cheaper compatible Signetic series in most cases. My choice to use ICs was based on a desire to finish the project within a reasonable time - which I did. There would have been too many parts going all-discrete. Of course discrete transistors were used as lamp drivers, to drive the core memory select lines, and in the voltage regulators. At least thirty years on, it's hard to imagine that there are people who haven't adapted. Even using simple digital ICs, you have to know a little about the internals of the family to avoid pitfalls - and to interface to other families. Analog ICs require more understanding. SNIP On the other hand, there is validity in constantly thinking through whether something should be done with transistors or ICs. Or with a $2 microcomputer. IMO, evaluating the trade-off between hardware and software is just as important. Where should one draw the line? My hobby RF experience has mostly been limited to VHF frequency converters. OTOH I assembled the first FM-stereo broadcast station in the Washington DC area, WHFS 102.3 MHz. The "components" were rather large: an HH Scott stereo generator, an RCA "iron fireman" FM exciter, and a 1 kW power power amplifier that had seen service a number of other places. I built a frequency-multiplier / IPA between the exciter and the 4-400 finals, and the power supplies including that for the finals. I built the stereo audio console for the station; my memory is a little hazy after 40 years, but I think the console used some audio ICs. SNIP 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. As someone else said, engineering is making what you want from the parts that are available. 73 de bob w3otc |
#6
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![]() "Michael Black" wrote in message ... But when building with an IC, you will have to actually build something around it in order to get something useful. SNIP 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". Over 30 years ago I homebrewed a PDP-8 work-alike computer. It was based on the PDP-8 instruction set. I've never seen PDP-8 electrical or detailed logic diagrams. I used ICs, but none more complex than a 4-bit adder. The 7400-series was then too expensive for me, so I used a cheaper compatible Signetic series in most cases. My choice to use ICs was based on a desire to finish the project within a reasonable time - which I did. There would have been too many parts going all-discrete. Of course discrete transistors were used as lamp drivers, to drive the core memory select lines, and in the voltage regulators. At least thirty years on, it's hard to imagine that there are people who haven't adapted. Even using simple digital ICs, you have to know a little about the internals of the family to avoid pitfalls - and to interface to other families. Analog ICs require more understanding. SNIP On the other hand, there is validity in constantly thinking through whether something should be done with transistors or ICs. Or with a $2 microcomputer. IMO, evaluating the trade-off between hardware and software is just as important. Where should one draw the line? My hobby RF experience has mostly been limited to VHF frequency converters. OTOH I assembled the first FM-stereo broadcast station in the Washington DC area, WHFS 102.3 MHz. The "components" were rather large: an HH Scott stereo generator, an RCA "iron fireman" FM exciter, and a 1 kW power power amplifier that had seen service a number of other places. I built a frequency-multiplier / IPA between the exciter and the 4-400 finals, and the power supplies including that for the finals. I built the stereo audio console for the station; my memory is a little hazy after 40 years, but I think the console used some audio ICs. SNIP 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. As someone else said, engineering is making what you want from the parts that are available. 73 de bob w3otc |
#8
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In , (Michael
Black) wrote: 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. Adapted? Yes. I have built countless devices around IC's of just about every shape and size. But I didn't design or build the -circuits- (i.e, the amps, the oscillators, the comparators, the negative impedance converters -- the network of active and passive components that make the device do what it does), I just followed the instructions provided with the chip and connected the dots. 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. The "level" of construction is the issue. It's one thing to homebrew the components, but another to homebrew the circuits. I understand what you and everyone else is saying, that "homebrew" can include the use of pre-packaged circuits as components, that it's just a different "level" of construction. Some might even think that building something from a kit is homebrew. I don't. Somebody else "brewed" the circuit -- the kit-builder simply assembles the components (connects the dots). 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. Superhets aren't that complicated, and neither is crystal mixing. Regardless, crystal mixing can get expensive. 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. Not true. Try linearizing a VCO and using a stepped voltage divider, then beating the output against an OCXO for drift correction. It's an old method, but it still works great. And it's a lot less complicated and expensive than using multi-bit comparators, parallel ripple counters, a parallel-to-serial converter (because there are very few parallel PLL chips anymore), BCD rotory switches or a decimal-to-binary converter, phase detectors, prescalers, etc. And notice that you still need that pesky reference oscillator! There is so much that can be built nowadays that virtually nobody would consider building in the tube era. I agree. But I didn't say that every homebrew project must be built with tubes. 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? You're getting close.... 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. That was my point initially. 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. And that, too, is a very good point. Notice that it works both ways -- I see a lot of homebrewers getting stuck in an 'IC rut'. 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. And the synth will be more accurate than using a prescaler, even a dual-modulus prescaler. But I made the mistake of assuming that he knew the difference between the two methods and had chosen the prescaler over down-conversion for reasons unmentioned. -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
#9
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Frank Gilliland ) writes:
... 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 Hello Michael. Down-conversion has been considered, but quickly dismissed. The sysnthesiser I need is a tool to be used for a wide variety of projects: projects that include modulation. Down conversion of frequency preserves any applied modulation. The prescaler and subsequent dividers filter out modulation so that a true phase lock may be achieved. This is especially true with WBFM where the total divide rate must be greater than 10000 to achieve a phase lock. NBFM, with a minimum modulating freq of, say, 250Hz, still needs a divider to divide by more than 60. Down conversion could make a simple synth if modulation were never to be used. I intend the project area to be both TX + RX, and to become a "building block" for a variety of circuits. Anyway, I have received a lot of response. My original question was "is there a good cheap source of prescalers" (but in a long-winded way) and this I have received. Many thanks to you and all who have given me positive suggestions. Unfortunately I will not be melting down horses hooves to make the glue to bond the home-beaten copper to a board to make the PCB. The only thin board available would be ready-made plywood, and that would not be "homebrew" ;-) BR Harry |
#10
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Frank Gilliland ) writes:
... 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 Hello Michael. Down-conversion has been considered, but quickly dismissed. The sysnthesiser I need is a tool to be used for a wide variety of projects: projects that include modulation. Down conversion of frequency preserves any applied modulation. The prescaler and subsequent dividers filter out modulation so that a true phase lock may be achieved. This is especially true with WBFM where the total divide rate must be greater than 10000 to achieve a phase lock. NBFM, with a minimum modulating freq of, say, 250Hz, still needs a divider to divide by more than 60. Down conversion could make a simple synth if modulation were never to be used. I intend the project area to be both TX + RX, and to become a "building block" for a variety of circuits. Anyway, I have received a lot of response. My original question was "is there a good cheap source of prescalers" (but in a long-winded way) and this I have received. Many thanks to you and all who have given me positive suggestions. Unfortunately I will not be melting down horses hooves to make the glue to bond the home-beaten copper to a board to make the PCB. The only thin board available would be ready-made plywood, and that would not be "homebrew" ;-) BR Harry |
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