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RF Toolkit ยท ITU-R P.525 ยท Hata 1980

Path Loss Calculator

Estimate radio signal propagation loss using 4 models: Free Space (Friis), Okumura-Hata urban, Okumura-Hata suburban and COST-231 Hata. Interactive tools with complete formulas.

Formulas Used

Free Space Path Loss (Friis)

FSPL (dB) = 20 x log10(d) + 20 x log10(f) + 32.45 (d in km, f in MHz). Reference: ITU-R P.525, classic Friis equation.

Okumura-Hata (Urban)

L = 69.55 + 26.16 x log10(f) - 13.82 x log10(h_b) - a(h_m) + (44.9 - 6.55 x log10(h_b)) x log10(d) with a(h_m) = (1.1 x log10(f) - 0.7) x h_m - (1.56 x log10(f) - 0.8). Valid for 150-1500 MHz.

COST-231 Hata (1500-2000 MHz)

L = 46.3 + 33.9 x log10(f) - 13.82 x log10(h_b) - a(h_m) + (44.9 - 6.55 x log10(h_b)) x log10(d) + Cm with Cm = 0 dB for medium city/suburban and 3 dB for dense urban areas.

Frequently Asked Questions

What is Free Space Path Loss (FSPL)?
Free Space Path Loss is the theoretical attenuation of a radio signal propagating in free space (no obstacles, no multipath). It depends on frequency and distance according to the Friis formula: FSPL (dB) = 20 x log10(d) + 20 x log10(f) + 32.45 where d is in km and f in MHz. At 2600 MHz over 1 km, the FSPL is 100.8 dB.
What is the difference between Okumura-Hata and COST-231?
The Okumura-Hata model covers 150-1500 MHz and works well for GSM and early LTE. COST-231 Hata extends the validity to 1500-2000 MHz to cover DCS 1800 and UMTS 2100. Both models are empirical, based on real measurements in Japan (Okumura) and Europe (COST). Above 2 GHz, 3GPP TR 38.901 models (UMa, UMi, RMa) are preferred.
When should you use an empirical model vs. an FSPL formula?
FSPL is valid for line-of-sight without obstacles (pure LOS), typically for point-to-point microwave links, satellites or very high altitude. For urban or rural mobile networks, empirical models (Okumura-Hata, COST-231, 3GPP 38.901) integrate average losses due to buildings, antenna height and vegetation, giving a more realistic estimate.
What is the Okumura-Hata urban formula?
L = 69.55 + 26.16 x log10(f) - 13.82 x log10(h_b) - a(h_m) + (44.9 - 6.55 x log10(h_b)) x log10(d), with f in MHz (150-1500), h_b base station height in meters (30-200), h_m mobile height (1-10), d distance in km (1-20), and a(h_m) a mobile correction factor. For a medium city: a(h_m) = (1.1 x log10(f) - 0.7) x h_m - (1.56 x log10(f) - 0.8).
Can these calculations be used for drive testing?
They provide a useful order of magnitude for sizing a test (defining an expected radius, estimating a link budget), but real drive testing measures the observed RSRP / RSRQ / SINR which accounts for shadowing, fast fading and interference. The comparison between model and measurement is the basis of radio tuning.

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