Welcome to Building Day IV!

Building Day IV -- the latest of the NOGA Building Days – promises to be another great day as we build an antenna tuner (actually a feedline tuner) using a classic Z-match design and a high-tech LED tuning indicator!

The Z-match design has been around just about forever. I remember it from my novice days (as good ol’ WN4JXO… don’t ask how long ago?) when we built them from giant air wound inductors and huge caps. More recently, the design has gotten a new lease on life in a number of tuner projects such as the BLT Tuner – and here, at Hacienda Hudson, in the latest NOGA Building Day project! This tuner is designed to feed a balanced line with no additional balun required. Neat!

The tuning indicator is an absorption bridge design as used in the BLT with an LED as a tuning indicator.

Using the tuner is easy! Flip the switch to "OPERATE", roughly peak the caps on receiver noise the flip the switch to "TUNE" and adjust the caps till the LED goes out. What could be easier?

We’ll be building our tuner with a combination of a retro wood chassis and a high-tech Plexiglas front panel. It’ll include a ground plane building area used for RF input with a two-terminal barrier strip for connecting the balanced line.

Of course, our project needs a snappy acronymic name. After millions of dollars of top-secret research our Bureau of Acronyms has come up with…


(Tuner for Electronic Transmitters and Radio Antennas Too!)

I hope you’ll enjoy building the TETRA 2 and especially the fellowship and fun of a fine group of fellow hams at Building Day IV!

With best wishes,

Steve AA4BW