The Gamma-Juhasz heavy AA battery fire control calculator, designed by István Juhász of Hungary, was manufactured and modified in Finland by Oy Strömberg Ab.

The Hungarian István Juhász had designed the Gamma-Juhasz predictor already in the 1920s. The predictor operated geometrically, using the setpoints to create a 1:40,000 scaled down predicting triangle, which gave the coordinates of the advance point. At the time, the predictor was extremely advanced as it was capable of following a target that was either making a turn or rapidly changing altitude. The device had a feature that was very useful in the harsh Finnish winter weather: a built-in electric heating system with a fan.

SPECIFICATIONS:

TRAVERSE:                      2x + 6300 mrad                  2x 6300

ELEVATION:                    -50 to +1380 mrad             -3 degrees 7/16 to +83 degrees 7/16

TARGET DISTANCE:       800–10,220 m                   

CHARGE-UP TIME:        0–4 s                                   0–6 s

FREE CORRECTIONS

Muzzle velocity:            -75 to +10 m/s                   -150 to +20 m/s

CREW:                               1+6 (1 NCO +6 gunners)

References: Vehviläinen Raimo et al., Itsenäisen Suomen Ilmatorjuntatykit 1917–2000, Sotamuseon julkaisuja I, Helsinki 2005; Palmu Pentti, Yön yli päivään – Suomen ilmatorjunnan vaiheita 1925–1990, Ilmatorjuntaupseeriyhdistys Ry, Helsinki 1989; Ilmatorjuntajoukot 1925–1960, Ilmatorjuntaupseeriyhdistys Ry, Helsinki 1963