Pre-Planck proportionality constant or ECM constant (k):

Soumendra Nath Thakur | ORCiD: 0000-0003-1871-7803 | Tagore's Electronic Lab, India | postmasterenator@gmail.com 

July 16, 2025

k = h(f₁/f₀) = 5.558 10⁻⁻³⁴ J·s. 

Where f₀ = 3.571 × 10⁴² Hz ; f₁ = 2.999 × 10⁴² Hz ; x° = 69.33°