Okumura-Hata curve calculation tool

By inputting the frequency, transmission power and distance it is possible to calculate electric field strength/received power in each environment.

What is the Okumura Hata curve?

The Okumura-Hata model describes radio wave propagation characteristics in various environments such as open spaces, suburbs, small to medium cities and large cities. Created by Yoshihisa Okumura, it was developed mainly to analyze radio wave propagation for mobile and cellular networks. The model is an approximation based on actual tests conducted a long time ago, however the data is still presently being used during construction of mobile phone networks.

These curves are meant to simulate propagation characteristics over medium to long range distances so for shorter distances (few tens of meters), the variation in the data becomes larger. Also it depends on the environment chosen so use this data only to indicate a margin where reception is possible.

Formulas used on this page

Basic formula for approximate propagation loss:

$$ Loss(dB)=A+Blog(d)-\alpha +C $$

Frequency: f(MHz)

Communication distance: d(km)

Base station antenna height: h_b(m)

Mobile antenna station height：h_m(m)

Common parameters

$$ A=69.55+26.16 \log⁡[f(MHz)]-13.82 \log⁡\bigl[h_b (m)\bigr] $$

$$ B=44.9-6.55 \log⁡⁡\bigl[h_b (m)\bigr] $$

Parameters under different conditions:

// Open land //

$$ \alpha=\bigl\{1.1 \log⁡[f(MHz)] – 0.7 \bigr\} h_m (m)-\bigl\{1.56 \log⁡[f(MHz)] – 0.8 \bigr\} $$

$$ C=-4.78\bigl\{\log⁡[f(MHz)]\bigr\}^2+18.33 \log⁡[f(MHz)]-40.94 $$

// Suburbs //

$$ \alpha=\bigl\{1.1 \log⁡[f(MHz)] – 0.7 \bigr\} h_m (m)-\bigl\{1.56 \log⁡[f(MHz)] – 0.8 \bigr\} $$

$$ C=-2 \biggl\{\log⁡\biggl[\frac{f(MHz)}{28}\biggr] \biggr\} ^2-5.4 $$

// Medium city //

$$ \alpha=\bigl\{1.1 \log⁡[f(MHz)] – 0.7 \bigr\} h_m (m)-\bigl\{1.56 \log⁡[f(MHz)] – 0.8 \bigr\} $$

$$ C=0 $$

// Large city //

When f ≦ 400 MHz

$$ \alpha=8.29\biggl\{ \log⁡⁡\biggl[1.54h_m (m)\biggr] \biggr\}^2-1.1 $$

When f ≧ 400 MHz

$$ \alpha=3.2\biggl\{ \log⁡⁡\biggl[11.75h_m (m)\biggr] \biggr\}^2-4.97 $$

In either case,

$$ C=0 $$

Applies approximately to the following conditions:

Frequency f(MHz)：150 MHz to 1.5 GHz

Communication distance d(m)：1 km to 20 km

Base station antenna height h_b(m)：30 m to 200 m

Mobile antenna height h_m(m)：1 m to 10 m