Over what frequency and targeted value of inductance are you measuring? If
you just want the inductance, it would be appropriate to connect the
inductor across the source port, Channel 0, only. One end of the inductor
goes to the center conductor of Ch 0 and the other end of the inductor goes
to the backshell of that connector. The inductance should be relatively
constant with frequency until you approach self resonance of the inductor.
Then it should dip close to zero, and above self resonance, become
capacitive. No real need to connect the inductor between the source port
(Ch 0) and the sink or receive port (Ch 1).
Dave - W?LEV
On Fri, Aug 13, 2021 at 12:08 AM Andrew Kurtz via groups.io <adkurtz=
[email protected]> wrote:
OK, I will ignore the rectum who likes to insult and bluster without
adding an iota of value to the conversation. I have attached a single
alligator clip to the pin of CH0 and to one end of an inductor. I can put
a second alligator clip to the pin of CH1 and to the other end of the coil,
or I don¡¯t have to. Either way, a signal goes into the inductor from CH0
and is reflected, and the nanoVNA correctly reports the inductance as part
of the Smith chart and correctly shows that transmission to CH1 falls off
as frequency rises. I believe it is working well, because I calibrated it
carefully. There is nothing on the outer conductor of either CH0 or CH1.
Do you think I would have better or more confidence results if I attached
something to the outer conductor? I don¡¯t even see anything that I could
attach there from my coil¡
Andy
On Aug 12, 2021, at 1:57 PM, David Eckhardt <davearea51a@...>
wrote:
Simple circuit theory taught in HS physics, and even some HS algebra
classes, teach this concept!! This is even hands-on demonstrated to
grade
schoolers in the Fort Collins, Colorado Museum of Science and Discovery.
Yes, grade schoolers!
OK, no more roasting and flaming, but certainly our present educational
system has fallen flat on its face!!
Dave - W?LEV
On Thu, Aug 12, 2021 at 5:49 PM G8DQX list <list@...> wrote:
Andy,
please forgive me suggesting that the below is a truly bizarre
interpretation. For all practical purposes anything connected to an SMA
connector implicitly requires two connections: a) a coaxial outer, and
b) a coaxial inner. If the coaxial outer is not connected, then the
return path from the inner pin is pretty much a matter of good, more
probably bad, luck, written undefined for short.
Always use a coax connection to whatever it is one is trying to measure,
even if using a special test fixture, such as when looking at chokes or
crystals. Then all the current flow paths are well-defined.
HTH, 73, Stay Safe,
Robin, G8DQX
On 12/08/2021 16:25, Andrew Kurtz via groups.io wrote:
All discussions of the NanoVNA suggest that the pin on the SMA
connector
attached to channel 0 is the only connection needed to look at
reflection
(S11).
--
*Dave - W?LEV*
*Just Let Darwin Work*
--
*Dave - W?LEV*
*Just Let Darwin Work*
