Online smith chart1/29/2024 ![]() I find that the potting is worth it to protect the board and components and keeping the toroid windings in place. There will be some change in characteristics after potting but nothing significant. On Smith Chart, decreasing the phase of the reflection coefficient means going clockwise on. Be sure to use clear epoxy, definitely don't use anything with metal fillers. Ximera provides the backend technology for online courses. I pot the assembled and tuned matching network with Gorilla Glue 5 Minute two part clear epoxy. And I find it easier to swap out toroids than to try to remove or add turns while the toroid is mounted on the board. ![]() This makes it easier to play with spacing to get a targeted inductance. There is also a link available in the program itself. copy to clipboard) There is a pdf help file online take a look in the files section. Some features may not available with other OS (e.g. This program was created for educational purposes. Rather than adding or subtracting turns on one toroid I wind two toroids with different number of turns. A small tool which allows all basic smith chart actions. Often you have to decide whether to use n turns or n + 1 turns on a toroid. The calculated inductance for toroids is not always close to actual value due to winding spacing and toroid material variance. Articles Smith-Chart Calculations for the Radio Amateur - Part 1 QST January 1966, pp. There are various discussions on accuracy but it will get you in the right ball park. The Smith Chart is a clever way of graphically solving impedance matching problemsit is still useful today despite the availability of computer based solutions. Premeasure the inductors and capacitors with the nanoVNA at the frequency of interest before using in the matching network. The nanoVNA measured high reactance impedances better than standard antenna analyzers designed mainly for SWR measurements. The readings were affected not accurate and consistent. ![]() There was just too much RFI from the laptop and power supply that was being picked up by the antenna. Some of my initial measurements where performed with the nanoVNA connected to a computer using nanoSaver software. When measuring ZL impedance use the nanoVNA by itself and use its file saving capability to retain the. If needed, I could remove the 10 pF and substitute a 5 pF or 15 pF capacitor to fine tune the match. I mounted a 47 pF NP0 ceramic SMT capacitor in the BNC connector itself, followed by a 15 pF and 10 pF parallel NP0 SMT capacitors on the protoboard that the matching network was built on. Smith charts are a standard tool used by many RF engineers, so it pays to know how to use a Smith chart for impedance matching. ![]() The mounted BNC showed around 7 pF capacitance, leaving about 71 pF of additional capacitance. I also measured the capacitance of the BNC connector using the nanoVNA and verifying with an autozeroing small capacitance meter. This made me decide to use a set of parallel capacitors so I could fine tune the value that will provide a close match, this turned out to be a good decision. Large changes in capacitor value will prevent the match to be close to the chart center, no matter the value of the inductor. Changes in the capacitor value keeps the network from moving along the 50 ohm constant resistance curve to the center. The most sensitive value seemed to be the capacitor. Matching circuit and related RF or microwave information as well as software downloads and links.Initially I looked at how the match varies with changes in the component values. Smith Chart for Transmission Line:The various properties of transmission lines may be represented graphically on any of a large number of charts. This page provides a collection of some of the BEST Smith Chart, s-parameter, impedance, admittance, smithplot (frequency,data) creates a Smith chart based on frequency and data values. This seminar contains material typically covered in one full day of instruction but is divided into five 90 minute web-classroom presentations. A Collection of Smith Chart Resources from Spread Spectrum Scene Online, smith chart rf impedance matching circuits smith chart rf impedance matching smith chart rf impedance smith chart rf smith chart smith smith chart chart rf rf rf impedance impedance impedance impedance matching matching matching matching matching circuits circuits circuits circuits circuits circuits A Collection of Smith Chart Resources from Spread Spectrum Scene Online, smith chart rf impedance matching circuits smith chart rf impedance matching smith chart rf impedance smith chart rf smith chart smith smith chart chart rf rf rf impedance impedance impedance impedance matching matching matching matching matching circuits circuits circuits circuits circuits circuits A Collection of Smith Chart Resources, The Smith chart is commonly used to display the relationship between a reflection coefficient, typically given as S11 or S22, and a normalized impedance.
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