SWR Tuning Indicator reinvented

Equipment
1

In the QST issue June 2026, pp. 33-34, Phil Salas, AD5X, describes in “A Simple Transceiver Protector and SWR Tuning Indicator” how the accuracy of the well-known resistive SWR tuning indicator with LED display can be improved.

Phil’s brilliant idea:

  1. Improvement of measurement sensitivity by eliminating the 0.7 V voltage drop of the RF rectifier diode and having this function taken over by the LED instead

  2. Improvement of display accuracy in the 1.8-54 MHz range by compensating for unwanted inductance through wiring using capacitors switched across input and output.

BTW, Phil built his SWR Tuning Indicator for use with his FX-4CR, even with 20 watts, so he used 15 W thick-film resistors in the measuring bridge.

I’m wondering if anyone has already modified their existing resistive SWR tuning indicator based on AD5X’s idea?

2 Likes
2

I am glad that Phil was kind enough to provide an excerpt from his copyright-protected original article at my request.

Many thanks again to Phil, AD5X, for his great support.

Have fun reading and adapting/building your own SWR Indicator(s).

SWR Bridge Detector by Phil Salas,AD5X_1
SWR Bridge Detector by Phil Salas,AD5X_12481×3509 467 KB

SWR Bridge Detector by Phil Salas,AD5X_2
SWR Bridge Detector by Phil Salas,AD5X_22481×3509 361 KB

1 Like