As we all know, a successful commodity station design should consider implementation of function, aesthetics, reliability, cost, production process and other factors, one-sided emphasis on a particular function or indicators generally are not a commodity radio, a successful product is Designers draw on work experience in a variety of factors compromise after completion. As an amateur radio class DIY kit, due to cost and limitations of the design team, only to highlight or emphasize a part of radio functions and indicators, and its overall functionality and performance can not be with the same price goods station par.
Cheap domestic DIY kit's main role is to provide you a study, practice, use of the opportunity, but not for the main machine used to go with us, they launched on the existence of such and such a lot of shortcomings and deficiencies. After all, a sub-price goods. I very much agree with the concept of a User: 70s DIY is no one else to buy or bad thing;
1980 DIY is to save money; 90 DIY want is feeling; 21st century DIY as is satisfaction; future may become burn DIY movement! DIY kit as a domestic consumers should keep a good attitude, all the package, as a toy to play, learning aids to look at, DIY is a "state" can be measured non-pecuniary, DIY process will be your ability has greatly improved and can acquire knowledge!
Moreover, the whole process is a DIY ordinary people can not understand. Of course, less than 800 yuan package shortwave transceiver whole paragraph may not be able to achieve a real sense of combat, the excellent design of functional verification only when the type of experiments, the performance of poorly designed not as toys.
Some beginner's friends did not get down to serious efforts to learn basic theory, but followed the public master quite difficult to do things, "not small streams, not into a river"! If you want to learn and study radio technology, from theory to practice (DIY belonging to a practice), returned from a practice theory is a shortcut. No theoretical basis for electronic technology enthusiasts to save money or if you assembled DIY kit to dispel the idea of it, advise you to make more money and do not go to buy a good machine assembly kit! Buy has assembled a good debugging actually lost 60% of the finished product of DIY fun. But from the perspective of the study to observe the novice to buy the finished weld Well there is still quite interesting, if there is no maintenance of equipment experience and testing methods, should be few and do not need to buy debug points instrument toy grade or SDK kit.
DIY many forms, their design is DIY, buy kit assembly is DIY, MOD product machine is also DIY, the finished machine (or components) should also be slightly modified the use of DIY. Is probably the most elementary simple machine maintenance and decommissioning of small change; then bought one of the senior point is not directly used in their devices to transform things; rice should be a one to eat, the road to go step by step, step by step by step a step to avoid detours.
Raising the level of their technology is constantly learning, use, exchange, demolition, installation, repair process of completion (as DIYer instrument must be ready enough, otherwise Mangrenmoxiang! Most basic instrument has a signal generator, digital frequency meter and oscilloscope) in order to further improve their level of radio technology. DIY activities often carried out only! Not personally do something, a lot of books inside the area, but after the fact, is a very critical thing would be difficult to grasp. For radio stations, now the real technology has gradually shifted to the details of the deal, the problem can be found only through DIY, and gradually learned to master these things.
Based on the DIY keen amateur radio DIY kit when it occurs, the lack of strong will, I have quickly caught up on their pursuit and obsession. So the past few years has been concerned about the development process of the domestic DIY kit, because I like so concerned about, huh. But then, from the current point of view, for the majority of domestic DIY kit, the situation is not very optimistic, oh, it seems more and more serious product homogeneity, no new breakthroughs, it started that way domestic DIY kit dawdle, do one day a monk hit one - muddling it? As a DIY kit of domestic hopeful enthusiasts, now say that it is a little bit disappointed. Why is disappointed that in the end it? DIY kit from just listed once considered a cheap second-hand radio and other similar products in the alternative, but now degenerated into tasteless tasteless, the most fundamental reason is technical flaws. A technically not yet fully mature products on the market can go very far behind? Estimates can not be! Packages removed for the time being we do not pretend to say that the rate of the problem, the effect on the reception of the problems is enough to make us wait to ear Satoru up.
One of the organizers of package rates loaded into alleged propaganda to study carefully, HF SSB radio equipment although simple assembly, debugging is simple, but can be practical type of radio equipment kit (parts level) assembly is not very simple, if there is enough equipment debugging is simple, but you just want to use a multimeter to add up to block digital frequency meter, like one good debugging a DIY work, I am afraid there will be no more than 60% certainty. debugging must have good The more complete test means (means of these tests is not necessarily the instrument level, the same can DIY) backing. For the use of DDS to do an oscillator (spurious high, make a good receiver) and BFO package of practical difference, then loaded "into a" higher rate (equal cost and design analog tuning machine performance levels but higher Debugging difficulty bigger).
2, a large number of packages are not housing, microphone, speakers, and other small accessories join line, although these things are not expensive, but you have to buy to look for, the cost of travel and time is not small, as the panel production is quite troublesome! A bunch of ugly parts barricaded exposed circuitry can cause severe visual pollution does not say, but also easily damaged.
3, only a few hundred dollars to do the LO DDS package to be less than 1 Hertz if stepper is easy, good manipulation interface is slightly harder, but relatively basic transceiver performance, this does not mean that advanced technology In commodities radio or receiver, I have not seen the DDS output directly as the first local oscillator, more solution is to use DDS generates a signal for a small tuft of stepping frequency synthesizer reference signal, then through a monocyclic analog PLL frequency synthesizer, the local oscillation signal output by the VCO. As a result, broadband DDS spurious interference signal by the PLL loop filter filters out, step small, simple circuit, high performance. A radio receiver reception performance is the most important, if the connection closing performance also can not guarantee, then pursue other else have no meaning.
4, the bipolar transistor formed by the analog multiplier circuit or the like for example for the NE602 mixer is used in the receiver to make a short-wave mixer, it is far less than the field-effect transistor dynamically balanced mixer , double-balanced mixer FET and Schottky diode double balanced mixers, all currently used by the bipolar transistor analog multiplier for the first mixer doing CW or SSB shortwave receiver kit, if its input end of the LC circuit tuned frequency selection can sing the grade as a toy, if it is a band-pass (including sub-octave band pass filter) broadband input is entirely functional verification type without practical value of electronic waste (I say may After a point, but I have been offering a reward, I saw someone bluster or personal attacks is nobody works out a decent performance, to analyze the reason is very simple - profit-driven)!
5, DIY kit development takes a lot of effort and labor, as the purchaser must respect their hard work, not to the sum of the price per one part to count their "profit", but from the other hand to consider, the hundred or so the cost of parts made of things in accordance with national standards SSB transceiver test, it is impossible to fully meet or exceed the original value of the yuan late 1970s stereotypes on older devices (very few indicators over twenty century stereotypes of high-end equipment is normal) That is one of two indicators do not think that a good product will meet or exceed XX radio grade of.
6, do not believe the "record" with the performance of the machine have much relevance. A friend once asked me: BAXXX loaded into XXXX kit with that thing still Communications HAM than 1000 km away from it, this thing is how? My answer: the more so the more publicity to prove that it will not do this! We have friends here with XD-D2B Communications over the United States, Canada and other countries, HAM, and I use MSR8000 (in the state) did not go to the United States and other countries over QSO, is not to say XD-D2B lot better than MSR8000 ah? There: December 12, 1901, Marconi realized from the UK and Canada, St. John's Harbour Cornwall between transatlantic wireless telegraph communication over long distances, and until 1907, DeForest only to the United States Patent Office to declare the vacuum triode patents, not to mention the electromagnetic environment in 1900 and now the number of the number of extremely poor, Marconi was used without any active amplification components such as receiver sensitivity performance indicators to achieve what kind of level can be imagined! As a reminder to please a few packages are installed in the propaganda of "cheap" toy-class suite reception desk reference when you do compare, for example, old-fashioned 339 receiver (DE1103 also, but it is best to give it the addition of LC tank frequency preselection), to avoid misleading beginners; while beginners should reflect how IC-7800, FTdx-9000MP Nobody said it QSO XXXXX kilometers away to the DX station?
7, DIY kit purchase price is higher than the actual components of the price of the sum of components, a $ 1000 DIY kit, the parts and materials fee must be less than 30% of the total price. As a few hundred dollars all shortwave frequency continuous adjustable DIY kit machine, integrated transceiver performance impossible at the same price with the second-hand goods station (material cost far more than 1800 yuan) compared. If you only want to spend 800 yuan to buy the price DIY kit assembly, the finished product within the scope of national standards would want to beat TRK-90 that two phones is wishful thinking! Of course, a handful of relatively narrow frequency range of amateur frequency single-stage or multi-segment machine, an extremely limited range of frequencies within the sense of hearing can be close to or exceed BWT133 or FT80C other full shortwave frequency continuous adjustable shortwave whole paragraph machines.
8, if you assemble the kit does not provide circuit schematics, NN spend hours assembling components do not understand the principle. In addition to show off your "My technique well - this is my DIY radio" other than purely as a welder when the XX hours. If the purpose is to learn, might as well buy back used goods machine repair learned more.
9, to date, made less than $ 800 full band shortwave receiver commercial DIY "kit" If in accordance with existing norms and standards radio is essentially a toy, within the context of national standards for the performance is far behind the same price to buy second-hand commodity machines (except products of Shaanxi flames field), and its SSB receiver performance even keep up with the installation of pre-selected input frequency LC tank circuit, variable antenna attenuation switched 455KHZ the SSB filter DE1103 (material costs less than 150 yuan) Radio! Of course, the individual's subjective sense of hearing frequencies more than million machine is credible.
10, if you want to self-development and the successful DIY "modern" radio, and use it as a radio amateur in welding school "weapon", first of all have to "sacrifice" spiritual, namely: an FT-1000D spend money, Buy a bunch of "junk", and these "garbage" is not a machine that can keep up with TRC-80!
11, the radio reading books, electronic technology, not to mention being a theoretical study; instrument is required; repair various types of radio stations is the minimum of; because studies do not need to buy a lot of electronic components, semi-finished products, machine is to be willing to throw away; successful joy was short-lived; organization kit is very troublesome; sell things scolded JS was criticized is reliable!
As a package developers should do the following
1, the package should be complete with all the little things: the microphone, speaker, socket, shell, knobs, internal wiring, etc.;
2, even "cheap" toy grade kit should also be able to do to make up the performance by the bipolar transistor consisting of analog multipliers such kind of IC NE602 mixer used for shortwave receiver on Dynamic is not high is true, but it does not mean can not be used, as a developer it should be the input preselection done, to avoid radio interference night long list (not to mention I no basis, 139A, 239,339, JS240 neither high dynamic mixers, how much better) embarrassing low results.
3, shall be announced prior to selling kit circuit diagram, so that buyers bottom of my heart (and I do not say anything intellectual property rights, and a considerable number of foreign kits senior radio station announced the drawings, something that you can technically strong to where to go).
4, as far as possible with domestic components. Do not boast about imported magnetic materials, quartz crystal how good ham Wuhan bought both inside stuff K2 are made in China, the other just by magnetic and quartz crystal does not completely determine the overall circuit inside the filtering effect and frequency stability.
Any one package have condensed the development team's efforts and technologies, reflecting the developer's love for amateur radio. The need to reach a minimum sales and other reasons, the development team had in terms of performance, functionality, reliability and assembly difficulty, debugging difficult, the total cost and other technical aspects and business aspects of compromises and trade-offs, and make a difficult balancing act. To make a high level of high-performance devices are a good teacher, but only those who can make a very low cost with high performance equipment is a high level of master!
Standing on the development side's position to be accounted for: the development of a suite of hard environment requires test equipment, high-tech talent and experience of using a lot of equipment, PCB and panel engineering costs, the risk of unsuccessful prototype costs, after the success of the prototype components must buy the whole package backlog waste fees, finance charges, service charges and so on. Finally accounting down, the same thing as a DIY kit to carry out his fear than the high cost of commercial production for at least 1/3.