Receivers – Page 6 – owenduffy.net

What does an Antenna Tuning Unit (ATU) do?

An Antenna Tuning Unit (ATU) performs a simple but important function in many transmitting systems.

Almost all things called an ATU are simply impedance transformers, and almost always, narrow band impedance transformers (meaning that when adjusted, they achieved the desired transformation over only a narrow frequency range).

ATUs come in a range of configurations, each designed for a specific set of characteristics. Above is the heart of a Palstar AT2K T Tuner, just three real passive components that are fully explained by conventional linear circuit theory. Continue reading What does an Antenna Tuning Unit (ATU) do?

Last update: 1st December, 2016, 10:25 AM

DJ9BV & F6HYE G/T formula

At (Bertelsmeier & Magnin 1992) formulas are given for calculating G/T from Sun/ColdSky Y factor in several Ham bands, and solar flux at 10.7cm. Continue reading DJ9BV & F6HYE G/T formula

Last update: 14th May, 2014, 9:31 AM

DJ3JJ’s 432MHz EME Yagi article in Dubus 1/2010

DJ3JJ wrote up some interesting experiments with Yagis for 432 EME (Haefner 2010). Continue reading DJ3JJ’s 432MHz EME Yagi article in Dubus 1/2010

Last update: 11th January, 2015, 9:44 AM

EMECalc v9.09 reconciliation issue

EMECalc v9.09 was opened, a model for 1296MHz created, and the “get IPS data” button pressed.

The report shows solar flux at 1296MHz to be 106SFU. Continue reading EMECalc v9.09 reconciliation issue

Last update: 11th August, 2014, 3:46 PM

Mining K5SO’s measurements of Sun noise

K5SO published an article in which he reported measurements of Sun noise rise over cold sky for K5SO, W2UHI and VK7MO.

Above is his graphical summary of the measurements. Continue reading Mining K5SO’s measurements of Sun noise

Last update: 26th April, 2014, 7:08 AM

Measuring G/T

This article explains how to measure G/T using the Sun. Continue reading Measuring G/T

Last update: 12th September, 2021, 7:43 PM

Checkout of EMRCalc quiet solar flux report

EMRCalc v9.09 contains a facility to fetch a current report of quiet solar flux from an online source.

Above is a sample report. Continue reading Checkout of EMRCalc quiet solar flux report

Last update: 26th April, 2014, 10:14 AM

EME path calculation based on G/T

A correspondent asked if it was possible to calculate the link budget for an JT65 EME path using the G/T worksheet at (Duffy 2014). Continue reading EME path calculation based on G/T

Last update: 22nd April, 2014, 8:43 AM

G/T spreadsheet update (v1.09)

For those who may have used or want to use my G/T spreadsheet tool I have discovered a defect in one cell’s formula. Continue reading G/T spreadsheet update (v1.09)

Last update: 19th April, 2014, 10:54 AM

Trying to make sense of the VE7BQH Yagi performance tables

VE7BQH publishes a table of Yagi performance data derived from a number of modelling programmes. The table is often used as a definitive reference of the overall merit of an antenna by buyers, makers and students for their own situation.

This article is mainly motivated at better understanding the G/T column of the tables. Continue reading Trying to make sense of the VE7BQH Yagi performance tables

Last update: 26th November, 2014, 6:24 AM