Resistors behave just as they do in a DC circuit, but the inductors and capacitors have the property called reactance. Some antenna matching units in my shack AC CircuitsĪll electrical circuits are a combination of resistance (R), inductance (L), and capacitance (C), that resists (impedes) the flow of current when alternating (AC) voltage is applied. A review of impedance matching will help explain why ATUs are used. Though these all look different, they have the same function they match the impedance of a “load”, such as an antenna, to the impedance of a “source”, such as a transmitter. On the left side of the photo below, an inexpensive automatic mini-ATU rests on a vintage manual tuner, while to the right is a much-modified $15 “eBay” portable tuner and an automatic MFJ-993B ATU. Why do I make this clarification, and why are they so popular regardless of what they are called? These are more correctly called Antenna Matching Units. If you operate on the high frequency (HF) amateur bands, you might have an antenna tuner built into your transceiver, or an external unit on your desk connected to it. In Part 2 I will cover the design decisions I made in building my own remote ATU and the details of the construction. In Part 1 of this article, I review some theory about antenna matching and the advantage of using a remote ATU. If option LC is chosen, values of matching L and C components are calculated exactly as described in the analytical model.I started working on this project in midsummer, and now as Autumn is fading away, it is almost finished. Line 3 is the switch for various types of simulations. If option 12 is set to noError, the simulator runs exactly as described in Part 2 - Analytical Model. If option 12 is not set to noError, then the errors specified in options 4 and 5 as appropriate. The simulator can run with no errors introduced (option 12 set to noError) or gain error (option 12 set to gamma), phase error (option 12 set to theta) or both. The max file contains the maximum values. The data file is one header line and 3600 rows as the simulator steps through 10 values of SWR and 360 values of the reflection coefficient phase angle. If you want a different directory, you can edit the source. The files are stored in a directory that is a concatenation of the HOME environment variable and /Documents/hamradio/Antennas/tuner/Simulation_output. There is no need to change them unless you have particular reason to do so. The default filename appears in the command list. ![]() The first two options set the names of these files. It validates the option and if is not a valid option it asks you to enter it again. By entering the number, you will get a prompt to enter one of the options in that feature or command. It has a number of commands that it displays in a numbered list. I will describe the operation of simulator through its user interface. ![]() I will have to look into it and maybe switch at some point. I recently noticed that Go has a command line library. The simulator depends on my command line library that can be found at: It is compact, expressive, and functional with a rich set of libraries. It is compiled, strongly typed, object oriented language. If you know C/C++, the code should be easy to read. The simulator is written in Go programming language. The first scenario is used in the design process, the next three are used for sensitivity analysis and design verification.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |