#94: What Effects Do Transmission Lines Have?

What effects on impedance do the 5 variants of transmission lines have?
Previous Video: • #93: What Effects Do D...
www.w0qe.com

[@e2jw]

Brilliant explanations - Thank you! I just discovered this tool a few days ago. Your descriptions of the circuit effects, along with the how you are operating the software (with tips and tricks) is awesome!

[@w0qe]

Thank you!

[@lakshminarayanaaithal1081]

I feel it would be even more helpful if you do it with VNA together with SimSmith and see the practical and Theoretical variation(PS: I'm talking about only tuning values not the transmission line)

[@w0qe]

Thanks and I can certainly do that is future videos. Larry, W0QE

[@embeddedtechnologies9425]

what is in the background of this software, so that it do lumped & distributed analysis at the same time, does it use FEA.

[@w0qe]

I am not the author of the software but SimSmith does not use finite element analysis. Rather it uses a system of matrix equations to do the analysis. There is a SimSmith user group at groups.io where you can ask the author of the program (Ward, AE6TY) for more details if you need them. Larry, W0QE

[@elwood.downey]

So does the path always form a circle centered at the point that is the Z0 of the line?

[@w0qe]

Elwood, A lot of people think this is the case but unfortunately that is not true. Set SimSmith to have the center of the Smith Chart to be 50+j0. Then set the load to be 25+j0 and put a 300 ohm lossless transmission line in series with the load. You will see the transmission line will cross the horizontal line at 25+j0 and 3600+j0. Just eyeball the center of the circle and it is 100+j0 which definitely is not 300+j0. Now change the center of the Smith Chart to be 300+j0 and now the center of the circle appears to be 300+j0. While all the points on the circle are the same no matter what the center of the Smith Chart is the center of the circle has no real meaning. If you need me to send you a SimSmith file showing this send me your email and I can email you the file. Larry, W0QE