On 13 mayo, 15:38, Jim Lux wrote:
Owen Duffy wrote:
lu6etj wrote in news:e57e2fbf-75a6-4014-a190-
:

Adding an ideal reactance of -155 ohms

Bit is not a fixed reactance, it is a transmission line element, and you
should model it as that, even if lossless.

Owen

In the Mosley case, judging from the writeup at the link supplied a few
days ago, the series capacitor is sufficiently short (a few inches?),
that it's probably safe to consider it a lumped element. Isn't it just a
wire in the middle of a tube.. essentially a coaxial capacitor.

True. Since delta f is small (aprox 2%), considering it a plain
condenser, reactance variation between 14 and 14.3 MHz is from 150 to
146.6 ohm; considering it a transmission line variation is from 150 to
146.8 -worthless-
In the worst case, thinking it as a coaxial condenser could have a
higher error on cable length calculation more than in the reactancev
variation with frequency.