End fed wires – another matching case study

A reader of my article End fed wires – new hams love ‘em asked about the performance of the matching transformer described at (Osborne 2014). (Osborne 2014) gives the transformer design above using a FT82-43 ferrite toroid with three turns on the primary. The concept is to adjust the antenna length and C1 for a … Continue reading End fed wires – another matching case study

A simple preamp for dynamic capsules to suit radios using electret microphones

A lot of radios are made today to use an electret microphone which has a higher output than common dynamic capsules and may require a preamp to comfortably obtain sufficient audio. This article describes a microphone + preamp intended as a drop in replacement for an electret capsule. An electret capsule contains an integral FET … Continue reading A simple preamp for dynamic capsules to suit radios using electret microphones

An inexpensive medium power tuner current balun for HF using Jaycar parts

This is a project to design and build a Guanella 1:1 (current) balun suited for up to 100W on HF with wire antennas and an ATU. For use with a tuner, the most important design criteria are: high voltage withstand; high common mode impedance; power handling. Last update: 28th January, 2016, 7:09 AM

Design / build project: Guanella 1:1 ‘tuner balun’ for HF – #2

Second part in the series… Design / build project: Guanella 1:1 ‘tuner balun’ for HF – #1 Design / build project: Guanella 1:1 ‘tuner balun’ for HF – #2 Design / build project: Guanella 1:1 ‘tuner balun for HF’ – #3 Design / build project: Guanella 1:1 ‘tuner balun for HF’ – #4 Design / … Continue reading Design / build project: Guanella 1:1 ‘tuner balun’ for HF – #2

Design / build project: Guanella 1:1 ‘tuner balun’ for HF – #1

This is a project to design and build a Guanella 1:1 (current) balun for use on HF with wire antennas and an ATU. First part in the series… Design / build project: Guanella 1:1 ‘tuner balun’ for HF – #1 Design / build project: Guanella 1:1 ‘tuner balun’ for HF – #2 Design / build … Continue reading Design / build project: Guanella 1:1 ‘tuner balun’ for HF – #1