The article reports a simple experiment on the balun described at Low power Guanella 1:1 tuner balun using a pair of Jaycar LF1260 suppression sleeves to assess the loss with near zero common mode current. This test would not subject dielectrics to high electric field strength. The balun above had the two wires at one … Continue reading Differential flux leakage in a Guanella 1:1 balun – an experiment
This article has been copied as reference for a new article from my VK1OD.net web site which is no longer online. The article may contain links to articles on that site and which are no longer available. I have been asked by a correspondent to comment in the context of my model of a Guanella … Continue reading Differential flux leakage in a Guanella 1:1 balun
A correspondent having read End fed matching – design review raised a similar design by PA3HHO which uses a#43 ferrite toroid as part of an end-fed matcher, see Multi band end-fed (English). The text and diagram are inconsistent, but to allow him the benefit of doubt, lets consider the FT240-43 with a 3t primary… … Continue reading End fed matching – PA3HHO design review
A correspondent asked me to review an end fed matching unit that uses a FT82-43 ferrite transformer to transform the high impedance of a 40m end fed half wave down to approximately 50+j0Ω. His design uses a primary (radio side) of 3t and secondary of 24t. Last update: 17th September, 2015, 8:43 AM
Transmit performance of 2m hand held transceivers reported relative field strength measurements for some transceiver / antenna combinations. This article documents a more careful measurement of the absolute field strength of one combination, and application of that knowledge to the other results. Measurements of field strength were done with Lou Destefano’s (VK3AQZ) VK3AQZ RF power meter … Continue reading Transmit performance of 2m hand held transceivers – absolute gain estimates
This Feb 2012 article has been copied by request from my VK1OD.net web site which is no longer online. The article may contain links to articles on that site and which are no longer available. Many designs have a ‘balanced output’ or an option of a ‘balanced output’, but what does that mean, and are … Continue reading Balanced ATUs and common mode current
This article documents my build of Lou Destefano’s (VK3AQZ) RF Power Meter kit. The power meter is based on probes using an AD8307 logarithmic detector. Above, the RF Power meter with two probes. (The ferrite sleeves were not part of the kit.) Last update: 9th December, 2014, 8:39 AM
My friend Richard found himself located on the margins of coverage of the local 2m repeater where multi path reception was the main problem, a but a little lift in signal would also help. This begs a small Yagi solution. Last update: 23rd October, 2016, 10:20 AM
A reader of Why the preference for Guanella 1:1 current baluns for HF wire antennas asked if a similar model can be built for a Ruthroff 4:1 balun. Hams tend to insist that the Ruthroff 4:1 balun cannot be represented by transmission line elements, but they are quite wrong. Last update: 9th November, 2014, 8:57 … Continue reading A SPICE model for a Ruthroff 4:1 balun.
I am often asked why I recommend a Guanella 1:1 balun with high choking impedance for most HF wire antennas over voltage baluns and 4:1 current baluns. This article explores the topic using SPICE models for a voltage balun, 1:1 current balun, and 4:1 current balun. Last update: 6th February, 2016, 7:15 AM