My question concerns the well known Struthers RF Wattmeter TS-1285/URM-120 which
has three big plug-ins (2-30 MHz 1000 Watts, 25-250 MHz 500 Watts, 200-1000 MHz
500 Watts).

Differently from all common wattmeters, the Struthers meter has a perfectly
linear scale. How could they achieve that?

On QST magazine (May 1996, pag. 77) K3BRS states that replacing the diode with a
different type would cause the initial part of the scale to become very
inaccurate.

Does anyone know of special diodes resulting in a linear wattmeter scale?

73

Tony I0JX