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"Ian White, G3SEK" wrote in message ...
Avery Fineman wrote: One thing that all should remember: Electrons don't care about "neat" construction. "Neat" gets something past inspectors, appeals to customers, looks mighty fine and "professional" in photographs. Electrons don't care for any of that. Fields and waves only care about placement of conductors and nearby dielectric material. [...] Right on! But...if one is familiar with RF layout through experience and a "feel" for lead placement and lengths, perf can be used on up to 70 MHz. That is NOT recommended for beginners who have just memorized Ohm's Law. Wish I knew how to pass on that "feel" for RF layout to other people. It's easy to explain to someone why their existing layout doesn't work, but more difficult to make positive recommendations so their next attempt *will* work. I once wrote an article about that for RadCom, which was lifted by the ARRL Handbook and survived for some years as part of the Construction chapter as 'From Schematic to Working Circuit'. That chapter, taken as a whole, is a pretty good basic reference. But in the end, there's no substitute for your own experience. Just build and build and build. Notice what works, and what doesn't... and then the trick is to understand why. For this kind of project, I very often use PCB design software to work up the layout, but don't always etch a board. Just as often, I cut a piece of single-sided board, tape a 1:1 printout of the PCB design onto the board and use it as a drilling template. Then I hand-wire the underside using the layout as a guide. I cheat a bit. Originally an illustrator, I sketch out the foil paths on vellum 1:1, mark the drill holes and use the vellum as a small center-punch guide. The paths are then painted in with lacquer, free-hand, using the vellum as a guide. The lack of those paper-graphics skills is why I use the PCB software. Heck, I even use it for roughing-out stripboard layouts, to try to maximize the use of the strips. In Europe there's a gadget called a Dalo resist pen which is made specifically for hand-drawing on PCBs. It has a fine fibre tip and very thick, quick-drying ink. It's very expensive for what it is (namely a not very good fibre-tip pen) but with care it can be quite effective. As many people already know, the Staedtler marker pens (waterproof/ wasserfest grade) are excellent for touching-up photo and iron-on resist patterns, but they're not as good as the Dalo for filling large areas. Those Dalo pens are nothing but lacquer pens... Sharpies, laundry markers....even other brands of common permanent markers will work..........you can get by cheaper and have a better supply of tip sizes from ultrafine for smt work to xtra large that will cover ground planes nicely. Other permanent markers will also work. Stadtler pens are nice too, dont know their chemical makeup but they are tougher to remove than sharpie lacquer pens with solvents. I do surface mount by hand with a double ended sharpie, one end has the normal fine tip and the other end has the ultrafine tip. I used a piece of clear plastic to layout the patterns for common soic and surface mount resistor capacitor pads and drilled these out with a very fine drill bit used for drilling out small gas appliance orifices, it works great Anyhow.....I have used perfboard for projects before, its quick and if you take your time you can do some really nice work. I have also used g-10 with the copper completely etched off for projects that used larger components where it was easier just to used 18 gauge wire underneath as opposed to ridiculously large traces. For hobbyist purposes perfboard is fine.......its making sure the circuit works and works reliably that counts. |
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