Here is a Smith Chart plot with the locus of points of every impedance (resistance and reactance) that results in a mag reflection coefficient of 0.33, and an SWR of 2:1 I chose to originally plot RL as negative just to match the shapes of the reflection coefficient and SWR curves. I did note that the NanoVNA save software allows the user to plot RETURN LOSS as either a positive quantity or a negative quantity. I am still learning a lot about these Nano VNA's and how to interpret their graphs. That's tough to cover the entire band without an antenna matching device somewhere. So on 80m, my favorite parts of the band are at the low end (CW and Digi modes around 3580 kHz) and the very top end with PHONE nets around 3990 kHz. Of course, hams do not operate on a single frequency, but QSY on a band. My 9th grade understanding of SWR and Smith Charts tells me that everyone can "see" the Bull's Eye on a target as the goal in darts, and in antenna matching, the goal is a perfect match to a 50-ohm feed line at some frequency. RETURN LOSS (as a positive number, in dB) was not a term I was familiar with before playing with this Nano VNA. The larger the radius (centered on 1.0 as 50 ohms) the higher the absolute value of reflection coefficient and the higher the SWR. I was hoping to get some feedback on is this portrayal of |reflection coefficient| or rho as the radius of a circle on a Smith Chart.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |