Thanks, Jim. Those are the types of off the wall ideas I'm referring to. Kind of the old 'Whack on the Side of the Head' (Roger Von Oech) type of thinking. Great book series by the way.?
Cheers,?
Larry
On Wed., 4 Aug. 2021 at 7:44 p.m., Jim Lux<jim@...> wrote: On 8/4/21 7:12 AM, Cliff wrote:
Maybe I'm missing something, but I can't think of any function of a VNA where a waterfall makes sense. It just isn't that type of measurement device.
YMMV
Another waterfall display application would be time history of EM
properties of something under test as temperature changes. For instance,
a VNA makes an interesting way to measure liquid water content in things
like lumber or meat. (we've all experienced the enormous difference in
EM properties between frozen water and liquid water when defrosting stuff).
Put your sample in a test cell, and let it go.
At work (JPL) we did some testing on measuring EM properties of various
materials by putting it in a resonant cavity, and changing the
environment (temperature, pulling a vacuum, etc.).? You sweep the S11
(or if you've got two probes in the cavity, S21) and look for the
changes in coupling or resonant frequency (which is strongly affected by
water content, for instance).
Recently, we've been running an experiment at extracting water from
Lunar Regolith by heating it at 30 MHz. Earlier tests used 2450 MHz
(from a magnetron), and we used a VNA to measure the match and adjust a
tuner to keep the sample in the "hot spot" of a waveguide cavity. At 30
MHz it doesn't change as much, but a VNA is a nice way to measure what's
going on, and how much power the sample is absorbing.
So I can think of a bunch of "wideband measurement over time" kinds of
applications - yes, many of them might be better done in another
computer and using the NanoVNA as a peripheral, but still, there's
plenty of interesting applications. (examining closed sarcophagi in a
pyramid, for instance)
Finally, one of the cool things about the NanoVNA is that it's cheap.
Who knows what kind of applications it might find when you're not
spending $100k on the test equipment.
