Re: ST scale endpoint

Andreas Poschinger

Hi Rick,

Are there examples for the use of the ST / S / T scales in its manual? Why are S T and ST the other way round? Is it maybe for impedance calculations when modeling wires as two terminal devices? There sometimes the normal trig with hyperbolic scales are needed together. The recipes for doing so are more or less complicated and work intensive. I never needed it it to do diring my studies; our respective Prof preferred the Smith Diagram, which most likely was more common in slide rule times to be used. Somehow there should be a reason for ST why to deviate from the more normal...

On slide rules on which the ST scale is just shifted by 18/pi the rad conversion is an integral part of its use as we have seen in the DeciLon manual. On slide rules with the rad tick marks not on the "folded side" or having no folded scales the use of ST also avoids the back set for certain angles and in any case simplifies the reading when having no need for changing the scale.

Best regards


Am 05.05.2021 um 05:25 schrieb Rick - WA6NDR:

For example, I have referenced the Pickett N-16-ES image that shows 5.74 at the index, with no ST scale mark at that value

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