Even a linear wire, not coiled, has some measurable inductance. At zero
length the display on the Smith chart, will show a single value of zero at
the extreme left of the real axis. That point on the Smith Chart is
0.00.... ± j 0 ohms. That represents a short circuit. As the measurement
point along the linear wire is increased, both the RF resistance (skin
effect) and inductance increase. Therefore, the measurement will depart
upward on the chart (inductive reactance) and to the right along the
central line on the chart. Since the vast majority of RF measurements are
assumed in a 50-ohm system (the industry standard except for the television
people), the chart is laid out around that value. ONLY the central point
(see the previous attachment) represents 50 ± j0 ohms.
The extreme right position along the central axis (real only) represents an
open circuit or theoretically infinite resistance.
An excellent tool both for analysis, modeling, and learning the Smith Chart
is SimSmith. It's free and available at the following URL:
That URL also contains many good tutorials addressing the Smith Chart.
More information can be had at the following:
Dave - W?LEV
On Tue, Apr 1, 2025 at 3:52?PM Jon via groups.io <vu2jo0@...>
wrote:
Dave,
One doubt about the Smith Chart: Why does the so-called resistive component
change as you move across the tracing? If it was the true electrical
resistance due to the ohmic resistance of the wire and feedline, it should
not change.
Forgive my ignorance. I have started using NanoVNA only recently.
73
VU2JO
On Tue, Apr 1, 2025 at 9:15?PM W0LEV via groups.io <davearea51a=
[email protected]> wrote:
Possibly the attachment will help.
Dave - W?LEV
On Tue, Apr 1, 2025 at 3:36?PM W0LEV via groups.io <davearea51a=
[email protected]> wrote:
Beware of most YouToob presentations. Those by the "big boys" which
offer
their instruments for lots of $$$$ are good and solid. Many of those
by
amateurs or "self proclaimed experts" are flawed. Take anything on
YouToob
with a huge grain of salt!!
Dave - W?LEV
On Tue, Apr 1, 2025 at 1:59?PM Zack Widup via groups.io <w9sz.zack=
[email protected]> wrote:
If the video on Youtube notes that the impedance should be zero, it
is
incorrect. The THRU impedance should be 50 ohms. I just checked on
three
NanoVNA's, and they all measure 50 ohms.
Zack W9SZ
On Tue, Apr 1, 2025 at 8:48?AM Paolo via groups.io <paolo.vecchi=
[email protected]> wrote:
Hi, I have seen a video on Youtube…
NANOVNA analizzatore di antenne: come usarlo (
)
youtu.be ( )
( )
Inviato da iPhone
Il giorno 1 apr 2025, alle ore 15:39, Dragan Milivojevic via
groups.io
<d.milivojevic@...> ha scritto:
? Port 2 is 50Ω as it should be, why do you imagine that it would
be
0?
On Tue, 1 Apr 2025 at 14:14, paolo.vecchi via groups.io
<paolo.vecchi=
[email protected]> wrote:
I buyed a nanovna H 3.6. When I try to calibrate it, after the
full
procedure, if I set a Smith diagram and I connect THRU the two
ports
using
the supplied cable the value is 50 ohm instead of 0. I resetted
and
repeated the calibration a lot of time but with the same result.
Can
you
help me? Thanks
<
Virus-free.www.avg.com
<
<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
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*Dave - W?LEV*
--
Dave - W?LEV
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*Dave - W?LEV*
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Dave - W?LEV
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*Dave - W?LEV*
--
Dave - W?LEV
