A recent long running thread on QRZ entitled “True balanced auto-tuner” was sure to tease out some pretty woolly thinking… the word “true” was enough to signal the outcome.
There are only three words in the title, we can dismiss “true” as a harbinger of woolly thinking, and though people will argue the toss on the appropriateness of the term “auto-tuner’, most people share an understanding of the meaning. “Balanced” is another problem altogether.
After thirty odd posts, there has been no definition or discussion of the term balanced, or its advantages or disadvantages.
One of the recommendations by several posters is the old is new again solution, the once popular link coupled tuner and the work of W5ZQ featured in one of those recommendations.
W5ZQ and WW8J
Topology
W5ZQ describes a tuner inspired by WW8J. W5ZQ extended the design and provides a writeup on optimising balance.

Above is W5ZQ’s partial circuit. In the article he describes and shows:
- adjustment of the grounding point of the output tank; and
- current meters which presumably attach to J2 and J3.
Key to analysis of the topology is that the centre of the output inductor is grounded. This results in the circuit tending towards equal but opposite phase voltages on the output terminals. Continue reading True balanced tuner
Last update: 22nd May, 2020, 12:34 AM