Products > Test Equipment

Smitih Charts, still relevant in 2024?

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W4PJB:
A little backstory on this question. Recently I met with a seller to look at an HP 8714 ET network analyzer. The seller was a retired engineer from, let's just say, a large radar company that we've all heard of.

I asked if the unit had a Smith Chart, and he literally laughed at the idea of still using one. According to the seller, nobody in his former employer used Smith Charts for decades, and even remarked it would be laughable among his peers to use one.

Now I'm certainly no EE, just an idiot learning electronics who also likes playing with radio and antenna systems. I'm sure there is a lot a VNA can do I'm not familiar with (thus the reason to get one, to learn) beyond what a Smith Chart can produce. So, are Smith Charts really a thing of the past in most professional environments? Or do they still find common use by those who actually do this for a living?

Of course, it's also possible he was simply downplaying the fact that his unit didn't have one, so I would still buy it (I didn't). But it did get me to wondering  :-//

ZigmundRat:
Why wouldn’t it be? Tabular data does not give you the visual representation and intuitive insights that the Smith Chart provides. You can find complex impedance and reflection coefficients at a glance. I think your engineer was a snooty know it all type that wanted to hold their ‘superior’ knowledge over you.

paul@yahrprobert.com:
The Smith chart is a mapping from the complex reflection coefficient (the rectangular grid) to the complex impedance Z=(ZL-Z0)/(ZL+Z0).  In the bad old days of slide rules it would take you quite a while to do that complex arithmetic by hand, and so Smith charts were very handy.  Nowadays with computers you don't need Smith charts.  Some people still like them as a way of visualizing things, but if you're handy with Matlab, Octave, or Python you can do things quicker and way more accurately.
While we're at it, lets get rid of VSWR and just talk about reflection coefficients (voltage or power).

Wallace Gasiewicz:
HP 8714 HAS a Smith Chart

Bud:
The "engineer" you spoken to was a clueless moron. Likely was a paper pusher, a mechanic or a janitor at the "large radar company that we've all heard of".

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