>
>Thank you for all the replies to my question about the grid term resistor
>selection.
>
>Although I haven't had time to go back to Rich's site yet, I'd like to
>ask the 2nd half of the question.
>........
>With my TS-940's larger output, I'm trying to choose the optimum value
>for 4CX1000 design (or similar). Would this exciter allow me convenience
>in selection of the termination resistance.
? The practical choices are 12.5-ohms, 50-ohms, 200-ohms and 450-ohms.
Less ohms means better stability and swr. The trade-off is more watts of
drive are needed.
>
>Also, would someone detail the term "triple bypass" the cold side of a
>resistor. Three separate types of capacitors, three different capacitors
>or three capacitors- same value in parallel?
... t
? ... three capacitors of different values, in parallel. . . Above
it's self resonant frequency, every capacitor looks inductive. Thus, to
optimally bypass a wide range of frequencies, several capacitors of
different values are better than a single value. For example, 0.02uF is
a fair bypass below 5MHz, 0.002uF is a fair bypass up to 30MHz or so.
100pF is a pretty good bypass at 100MHz. . Other values can be used.
Lead lengths are important. (note -- A vhf bypass on the cold-end of
the grid terminating resistor is important because it improves vhf
stability.)
- later
Rich...
R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures
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