BACKGROUND INFO, LEGAL ASPECTS, CAREFULNESS ETC (things which are supposed to be understood and not repeated with each new elsketch project page) OVERVIEW OVER ONLINE AVAILABLE ELSKETCH PROJECTS -- -- THESE HAVE ALL BEEN CAREFULLY STUDIED IN REAL LIFE, NOT JUST AS AN EMULATION ON A COMPUTER, AND FOUND TO WORK AS PROMISED; NOTE THAT SUCH AS AM MW RADIOS IS -- FOR ANY LONG-RANGE USE -- EXTREMELY TIED UP TO ALL SORTS OF WEATHER CONDITIONS AND THE EXTENT TO WHICH IT IS NIGHTTIME ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ For the G15 Multiversity: Background works Also part of the Stamash Educational CenterS, SECS For general info about G15 Yoga6dorg see also In general terms, we might use the following vocabulary: Each Elsketch project constitutes also a report over successfully completed electronics development and implementation work, in a sense a bit of 'neopopperian research', intended to be replicated in an improvised, intuitive, playful way by anybody who likes to educate herself in this way. This report is dated August 15, 2013. For general info about copyright confer the spirit of honoring acknowledgements as found in our ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ Elsketch: Winding your own variable capacitors for the 1st radio module -- unbearably easy, given some metal paper, plastic and glue, and stuff [note: for ease of composing the materials, frequent mentions in the Elsketch texts are made of things which belong to the future -- future Elsketch activities include making even a whole G15 computer, and parallel activities are also referred to in the same manner, such as the chemical educational activity we have named Atomlite. apart from these references to things not yet done as if they have been done, each elsketch project describes a project actually carried out to success, and well tested, and fully doable in the present by following the instructions.] You've got the radio, you want to loosen the prefabricated variable capacitor and make your own. You already have read the starting-point for this radio. You have perhaps already played around with your own ferrite coils. I'll take the liberty of going straight to the technicalities here, since those other two descriptions around the 1st radio module allowed for plenty of philosophising. THE WAY Cut metal paper -- thin leaf aluminium for instance, or another type of metal that fairly easily conduct electricity -- about the size of half a normal sheet of paper, or less, say 18 times 13 centimeter. Cut off a luxuriously large corner. Get the type of copper wire which is composed of myriad tiny copper threads. Rip off the isolation. Spread the copper threads out. Get a little tin on some of them, both sides of the copper threads, with the tinner -- just a tiny little bit, no heavy drops (just smooth the tin along the copper, so as to dress some of the copper threads up with tin, it's a kind of lingerie for the long legs of the copper girl). Put them on the metal paper -- so that you have the cleanest, most metallic part of the metal paper facing one another except for the isolation you're putting on it, with the wires on the other sides. In other words, you have two very clean clear straight metal papers near one another but they are isolated (at least one of them must be well isolated, but since they are thin it can be good for the strength of the whole thingy that both of them are isolated by strong glue or plastic). And we want to connect wires to these metal papers and we do so by spreading out very very thin copper threads of the type that's already typically used e.g. in higher voltage wires. We spread them out thin so that we won't create bumps in the papers. We have one wire that's absolutely on top (see image), and another wire that's absolutely underneath the bottom metal plate -- leaving the cleanest clearest parallel feel of the metal plates intact, we don't want to clutter anything. We want to be able to move those isolated metal plates on top of one another and then off one another, in a gradual movement. We want the copper threads to stick firmly to the metal, and not slide. But the metal film is usually too thin that you can tin the copper to it, heat will burn it up. That's why we spread it out and glue it on or push them on with plastic around and then glue or melt the plastic to push them. Put either loads of epoxy on one side so as to cover absolutely all of the metal without fail, yet somewhat smoothly, or glue plastic to it; or if you have a machine that can melt two sheets of thin plastic to a sheet of paper then very carefully let that machine melt the plastic around the metal paper -- with enormous attention to the copper threads, so they don't get stuck in the machine (there might be settings on some machines for more flexibility as to what it is fed with). Or, if you don't have glue, just put plastic around the metal paper, and try and tie the copper threads very gently in some tiny holes you try and make in the metal paper. Not a necessity but you can then make a hole in the proper corner and use a tool to bend some steel wire of a millimeter so as to keep them together in just that corner -- twirl the steel wire around and cut it so it doesn't touch any wires, and be sure it doesn't get anywhere near the metal here -- see photo. Also not a necessity in all cases but it can help to put a heavy non-metallic object like a stone on top of the whole to push them towards one another. Yeah, and put some kind of clip to keep the bottommost paper in place on the table or wherever you have your elsketch work. We want to slide the topmost paper with the bottommost paper being stable. THE RESULT It is great fun to engage in precise-tuning of the radio -- trying out different coils -- with the self-made capacitor, if you already have got the enthusiasm going for this kind of first-hand electronics radio and you started out using a prefabricated variable capacitor. You'll notice that for most coils, in most circumstances, given most types of design, the bulk of the stations come in when the papers are slided very much off one another -- more than in the pictures for some coils. But of great importance is the distance that the papers have. When you adjust, you could adjust by having a tiny corner of the topmost sheaf bent up -- the adjustment makes sense if you can move the topmost sheaf without giving pressure on it -- at least if you have sheaves that have a little bounce in them, so that there's naturally some air between the sheaves -- at least on the portion not having a stone on top. The more distance the metal papers have, the less is the capacitance, and the more the papers must be on top of one another to give capacitance. You can experiment with putting something like paper in between just for fun, to sense the difference (although consider that only an experiment, as paper shouldn't be made a fixed part of electronics equipment because of the natural consideration to have elements that aren't very fireprone at all). If there's too much paper, it will decrease the range of the capacitor too much. If the sheaves are touching one another too much, the capacitance is so great that it may go out of range that way. With a little bounce in the sheaves, and the stone on the side, you can get a lot of stability in the arrangement. If you're doing this step by step, making the radio module with prefabricated coils and variable capacitor, and also with an audio module, and have just made your own coil and your own variable capacitor, then there are two alternative obvious next steps: make your own audio module out of transistors, or make a own transmitter to get your own stuff across to your radio. Increased stability of the result: find some way to keep the wires that goes to the rest of the radio module, tinned to the copper threads, outside of the plates themselves. If the wires touch the plates sometimes, dangling over like you can see on the images on top, this dangling will tune and retune various stations -- in addition to the sweet shift of frequencies that always happens with MW as the belt of blackness moves with the Sun on the other side of the planet. As this belt of blackness moves, some stations that came easily in before the darknest part of the night fade and new ones come become available -- in addition to the changes that weather conditions provide. There is ABSOLUTELY NO REDUCTION IN QUALITY of reception when we make our own variable capacitor this way. There is no reduction at all -- neither of intensity nor of reception clarity or anything else. Radio capacitors are, simply, delightfully easy to make! Let's note in general that since 1nf is one thousand pf, and it takes easily five hundred nf -- five hundred thousand pf, that is, to have an easy time working with audio amplifiers, and they would enormously like such as 50 mf -- 50.000nf -- which is to say, 50 million picofarad -- for still better sound effects -- we are into the need to vary materials out of which we construct capacitors of when we go much higher up in farads than what we did in this project. For a good AM MW radio variable capacitor, up to some 200 pf is just perfect, just fine, and that's probably much what you just made, if you followed the instructions here. If you double the size of that you are still not anywhere near 1nf. To get all the way up to 1 mf this way we would have to fill a house with the capacitor. Instead, the notion is that we can put some chemical in between the two plates, or even make one of the plates into something special, so that we get a light chemical reaction that can preserve a little electricity for a little while, then release it; then allow a recharging. In this perspective, a rechargable large stable robust car battery is like an enormously huge capacitor of many farad, and it may be made of lead in sulphuric acid (sulphur dioxide in water). More about such stuff in Atomlite, where we construct all the more chemical Elsketch components. Let's go on! ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ BACKGROUND INFO, LEGAL ASPECTS, CAREFULNESS ETC (things which are supposed to be understood and not repeated with each new elsketch project page) ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________