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Roy Lewallen writes:
When you get _Experimental Methods. . _, look at the very first few pages -- "Getting Started". You'll find a nice drawing and some other information about "ugly construction". Incidentally, the method was first described and the term coined in the article "The Ugly Weekender" by Roger and Wes Hayward, in August 1981 QST. If you can get hold of a copy of this article, it has more about the method, as well as some other good information. If and when you do eventually decide to get a scope -- I've been surprised to see Tek 465 scopes going on eBay for about $200. That's an awful lot of bang for the buck. Roy Lewallen, W7EL Well last night I took some double sided copper clab board and cut off a small square. (By the way, what is the best way to cut this stuff?) I rebuilt the oscillator on there in 'ugly' style. And it was in fact quite ugly. It looked like something I would have done as a kid. But it worked! Now I'm sold on it. Hopefully I can get some pointers on improving my technique from the book. Now I have a new question though. The circuit is a Clapp based on the MPF102 JFET. When I compute the frequency range, it is close to the measured range but not the same; but there appears to be some capacitance that I can't account for, and its value seems higher than would be 'stray'. The circuit I'm using is basically like the one at http://www.electronics-tutorials.com...scillators.htm in figure 2, but without the extra parallel stuff on the variable cap. So I calculate the cap value by adding the var cap value in series with the caps labelled on that website as cfb-a and cfb-b. (By the way, what happens if those two aren't the same value?) Do any of the other capacitors in the circuit factor in? How much capacitance could my 'pill bottle inductor' be contributing? I was careful, but not extra careful when winding it. |
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