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?
ON9CD (Vandonselaar 2002) gives an expose on baluns for Hams.
Above is the first diagram he gives in support of his explanation. Continue reading ON9CVD on baluns
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
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
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
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
This article explains how to measure G/T using the Sun. Continue reading Measuring G/T
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
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
This article documents some comparison tests of:
- SimonK commit 1f75da384e5c83f83916aa752819ca6eed712565 afro_nfet.hex with COMP_PWM; and
- BLHeli v11.2 commit baaa4db600b5cd78752c9b4f580fd08d15f1f1f1 for Hobbyking Afro 30A.
Continue reading Comparison of SimonK and BLHeli on an Afro30 ESC