[AMPS] dearth of ham literature on parasitic osc.

[Robert Neece]

Lest anyone worry that the parasitic oscillation
thread is losing steam (or is that smoke?), I thought some
might find interesting a comment I received from a buddy of
mine off line:

>You know, the reason no one wrote for many years any
>"technical" article on parasitic oscillations is that the
>general level of technical expertise of the "ham community" is
>generally taken as "Sr Technician Level" [whereas] the level necessary
>to adequately understand and design around parasitically induced
>oscillations requires an understanding of parasitic impedances as
>a function of the layout, mechanical design and configuration of 
>matching networks... the math understanding necessary (circuit theory,
>complex algebra, trigonometry etc) is often well above the
>average ham's understanding or utilization.  There ISN'T a
>simple "cook book" method for designing parasitic suppressors... needs
>to be done on a case by case basis. 
>
>I'm constantly reminded of this phenomenon everyday in my job... in 
>theory one can make a Magneto-resistive head in one's basement; several
>technical books (ala cook books) describe it and model it well.  However,
>making one in reality is just a bit more tricky and there are a lot
>of practical "trade secrets" required to get them to work the way
>the theory says they do... and none of them really relate to the theory, but 
>relate to things such as controlling material composition while plating,
>cleaning processes, photolithographical processes etc...none of this
>is in the "literature"!
>
>FYI, an interesting "trade secret" that really isn't (ie everyone in the
>industry knows about this, primarily distributed by word of mouth and not
>in the literature....) is the fact that a specific amount of 
>"saccharin" (sugar substitute) is added to the plating bath.... this additive
>makes the crystal structure of NiFe very homogenous and small.  This trick
>makes it work.  Reason for the enhancement is not understood... it was
>found at IBM by a researcher droping his coffee into a plating bath and
>voila!  

73 de Bob, K0KR

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