z match

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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.
[ Hits: 69 | Votes: 0 | Rating: 0 ]

Half-Size 6 meter J-antenna - How to use a little known J-antenna characteristic to reduce a conventional 14 foot antenna to 7 feet. Perfect 50 Ohm match, same gain, no radials.
[ Hits: 63 | Votes: 0 | Rating: 0 ]

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 ]

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.
[ Hits: 76 | Votes: 0 | Rating: 0 ]

RF Choke with Bifilar Windings - This article presents an RF Choke featuring an 11-bifilar turn winding of #14 house wire on a Fair-rite FT240-31 toroid. The choke is enclosed in a 3D-printed case from Thingiverse, though this may pose thermal concerns at higher power levels. With SWR concerns up to 30MHz, the author plans to employ two series chokes at the rig input for improved performance. This choke offers versatility for portable use, with potential mismatch resolution using an antenna tuner. Further testing is anticipated upon the arrival of new cables.
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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.
[ Hits: 76 | Votes: 0 | Rating: 0 ]

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 ]

Portable T-Match ATU - Homebrew Portable T-Match ATU, VK1AD Portable T-Match Antenna Tuner (ATU) mounted in a plastic case, T-Match ATU Schematic – 3.5 to 52 MHz power rating 80 watts
[ Hits: 103 | Votes: 1 | Rating: 8 ]
Homebrew Z-Match Transmatch - For this project, I decided to try my hand at building a Z-Match tuner from scratch. This type of tuner has been around for a while. While the Z-match can take on several variations, what distinguishes it from other circuits is that it is a resonant circuit that uses a fixed inductor.
[ Hits: 132 | Votes: 0 | Rating: 0 ]
QRP Z Match Antenna Tuner Project - A Home made antenna tuner for QRP transceivers. This small tuner is the ideal for portable operations with random length wires or whenever you have not a resonant antenna.
[ Hits: 108 | Votes: 1 | Rating: 10 ]

20 W HF Power Amplifier - A HF power amplifier with a push-pull of AFT09MS015N. The (small-signal) gain of the amplifier is around 26 dB in the lower HF band and goes down to about 24 dB on the higher end and still around 21 dB at 50 MHz. Its input matching is relatively good at the lower HF and degrades above 10 MHz.
[ Hits: 175 | Votes: 0 | Rating: 0 ]
Building a Robust PL519 Tube HF Amplifier - his article explores the construction of a PL519 tube amplifier, utilizing Ulrich L. Rohde N1UL's insights. Focusing on a modest 25W continuous output, the design ensures robustness with forced air cooling. The detailed breakdown covers input matching, screen grid voltage generation, bias adjustment, anode power supply, heater power supply, and monitoring circuitry, providing valuable guidance for ham radio enthusiasts.
[ Hits: 71 | Votes: 0 | Rating: 0 ]