impedance match

37 links - and 1 categories

Build a Lightweight 15m Yagi Antenna: Simple Design for Impressive Performance - In this article, Steve G0UIH presents a straightforward guide for constructing a lightweight 15m 3 Element Yagi antenna with impressive performance metrics. With a focus on ease of construction and efficiency, the design boasts a nearly 8.2dbi forward gain and 30db front to back ratio. Utilizing readily available materials and a hairpin match for impedance matching, this Yagi offers broad bandwidth and simple tuning for optimal operation across the 15m band.
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The Ugly MacGyver 6 meter J-pole Antenna - Essentially, a J-pole is a 1/2 wave resonant antenna connected to a quarter wave matching stub. The feedline is connected at a point on the matching stub that is at the feedline's characteristic impedance. The result is 3/4 of a wavelength on one side and 1/4 wavelength on the other side.
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80 Meter Shortened Ground Plain Antenna - This antenna is a vertical loop antenna mounted on a 8 meters high grounded mast with an input impedance of 50 Ohms without a matching device
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Extended Double Zepp NVIS Antenna Calculator - Extended Double Zepp measurements for all ham bands, and online calculator. The antenna is constructed much like an ordinary Dipole antenna but with 5/8 Wavelength Elements matched with an added Impedance Matching Section of balanced feed line
[ Hits: 123 | Votes: 3 | Rating: 7 ]

DIY isolation transformers - Article about isolation transformer construction to perform optimal impedance matching. Winding the FCP isolation transformer, includes interesting table for Winding Turns and Lengths and Core Configurations for T300 T200 T400 toroids
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Multi-Band End-Fed Antenna Design for Limited Space ^new - This document details the construction of a multi-band end-fed antenna, suitable for situations with limited space for larger antennas. The design utilizes a 1:49 to 1:60 impedance transformer to match a half-wave wire antenna fed at one end. Compared to a traditional dipole, this antenna resembles a highly unbalanced Windom antenna with one very long leg and a virtual short leg. The design eliminates the need for radials but relies on the coax cable shield for grounding. The document recommends using at least 10 meters of coax and installing a common mode filter at the entry point to the shack for improved performance.
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End-Fed Half-Wave Antenna for 20m 40m 80m - How to Design and Build a Field Expedient End-Fed Half-Wave Antenna for 20m, 40m and 80m. This Shorty 80m EFHW comprises a 49:1 autotransformer (to match the very high impedance at the end of a half-wave wire), a half-wavelength wire for 40m (also a quarter-wavelength for 80m), a loading coil and a short tail wire. The coil and the short tail wire (about 6 feet) make up the other quarter wave on 80m.
[ Hits: 141 | Votes: 1 | Rating: 4 ]

To transform ot not to transform - Feed Lines - Transmission lines have many uses other than simply transferring RF power from one point to another. Impedance matching, baluns and filters are probable the most common of these.
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Angle of OCF L-Dipole Antennas - This page is a discussion about impedance matching by Off Center Fed dipoles in the Wide L-form. When a vertical or horizontal dipole is bent into a 90 degree L-form, the impedance drops about half.
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Tuning OCF L-Dipoles - The behavior of a straight dipole and its L-form is examined in terms of impedance and SWR. By adjusting the feed point or bending angle, impedance variation is observed. Impedance shifts symmetrically as the feed point deviates, leading to recommendations for optimal ratios. Model simulations aid in understanding and fine-tuning, crucial for achieving a 50 Ohm match. Practical tuning guidelines ensure efficient antenna performance.
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Adjusting HF Yagi Gamma Matches - There are many feed systems used in yagis over the years. Gamma matches are not as common as they once were. More typical are beta matches and T matches to convert the low impedance of a yagi to 50 ohm.
[ Hits: 132 | Votes: 1 | Rating: 10 ]
The Smith Chart - This tutorial introduces and explains Smith Charts, and then gives an introduction to impedance matching. Smith Chart is a tool to visualize the impedance of a transmission line and antenna system as a function of frequency.
[ Hits: 116 | Votes: 2 | Rating: 9.5 ]

The SPC Tuner - SPC, series parallel capacitance, tuner project. Built properly, it will match a very wide range of impedance. It also maintains good harmonic attenuation.
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Budget-Friendly QRP T-Tuner and SWR Bridge - In the pursuit of an affordable matching and SWR indication solution for the Pixie-based transceiver system this T-Tuner and SWR bridge unit, while not groundbreaking, proves to be a cost-effective performer. With real-world impedance testing yielding a worst-case loss below 0.9 dB, the unit efficiently matches all bands on 80 M to 10 M ham bands, making it a valuable addition to the QRP system.
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Interactive Smith chart - The interactive Smith chart enables users to navigate their way around a Smith chart, using simple discrete element impedance matching. This page allows users to try using the Smith chart, for education and interest purposes, without installing any software. Try changing the value in the load box to see the location of the impedance on the chart.
[ Hits: 285 | Votes: 2 | Rating: 9.5 ]

RF Impedance Matching Calculator - Calculates the network to match a line to a specific complex load. This online tool calculates the matching network necessary to terminate a line of the specified characteristic impedence Zo in a specific complex load impedence RL + jXL at a specified frequency.
[ Hits: 194 | Votes: 1 | Rating: 10 ]
Online Toroid Multi Calculator - This website provide online calculator for several values about a large variety of toroids. Freq/L/C/Z/Turns Calculator, Impedance Matching Network Calculator
[ Hits: 212 | Votes: 3 | Rating: 5 ]