This service offers a variety of propagation models for different purposes. For maximum speed the models are all written in a low level language (C++). Feedback from radio professionals and developers is encouraged to optimise the models where possible.
Use the P.1812 model if you are unsure. This is recommended by the ITU for general purpose applications and has been proven to be the most accurate model overall across a wide variety of technologies and environments.
For an up to date reference please refer to the official documentation.
| Code | Model | Purpose | Frequency Range | Minimum Tx Height |
|---|---|---|---|---|
| 1 | Irregular Terrain Model | General Purpose VHF/UHF | 20 – 20,000 MHz | 0.1m |
| 2 | Line of Sight (LOS) | Visibility testing | ~ | ~ |
| 3 | Okumura-Hata | Cellular | 150 – 1500 MHz | 3m |
| 4 | ITU-R P.1812 | VHF/UHF/Terrestrial | 30 – 6,000 MHz | 0.1m |
| 5 | SUI Microwave | UHF/SHF | 1900 – 11,000 MHz | 3m |
| 6 | COST231-Hata | Cellular | 150 – 2000 MHz | 3m |
| 7 | ITU-R P.525 (Free Space) | Reference model | 2 – 90,000 MHz | 0.1m |
| 8 | RADAR with RCS | RADAR for surveillance | 2 – 90,000 MHz | 0.1m |
| 9 | Ericsson 9999 | Cellular | 150 – 1900 MHz | 3m |
| 10 | General Purpose | General Purpose VHF/UHF/SHF | ~ | ~ |
| 11 | Egli VHF/UHF | General Purpose | 2 – 1500 MHz | 0.1m |
| 12 | HF NVIS | Ionospheric communication to 500km | 2 – 20 MHz | ~ |
| 13 | HF Skywave | Ionospheric communication to 10000km | 2 – 20 MHz | ~ |
Irregular Terrain Model
This service uses the Irregular Terrain Model version 1.4, also known as the ‘Longley Rice’ model. The ITM model is a long standing general purpose model developed by the US NTIA which meets most radio engineering requirements for frequencies between 20 MHz and 20 GHz. It is suitable for handheld VHF walkie-talkies to UHF microwave links.
This model has been superseded by ITU-R P.1812
Line of Sight (LOS) model
The LOS model is a simpler model well suited to super high frequency microwave links where LOS is key. It factors in terrain data and antenna heights to provide a clear yes/no result. It starts where the ITM model finishes at 20GHz and extends the maximum range up to 100GHz.
Okumura-Hata models
The Hata models were designed for Urban cellular planning which is evident by their focused frequency range (150-1500MHz) and minimum tower elevation of 30m. The model assumes the transmitter is higher than the average height of the rooftops.
COST231-Hata extension
The COST231-Hata model extends the Hata cellular models another 500MHz up to 2000MHz so is well suited to GSM1800 in urban areas.
ITU-R P.525 Free Space Path Loss
The free space model is a very simple model that assumes no obstacles exist between transmitter and receiver. It factors in the frequency and distance. It can be further enhanced with the addition of knife edge diffraction which will factor in terrain obstacles and antenna heights.
ITU-R P.1812
A path-specific propagation prediction method for point-to-area terrestrial services in the frequency range 30 MHz to 6 GHz. Diffraction loss is calculated by the combination of a method based on the Bullington construction
and spherical-Earth diffraction.
Testing against published accuracy papers has shown this to be more accurate for non-line-of-sight paths than the ITM model.
Diffraction models
In their native form, the empirical models (Hata, COST, ITU-R P.525) do not factor in the significant effects of diffraction caused behind obstacles. Knife edge diffraction has been added as an option.
For complex paths, Bullington, Deygout-94 and Epstein-Peterson models are also implemented for multi-obstacle diffraction in urban and rugged terrain.
Our diffraction models work with clutter also.
