Different Types of Radios Explained

kitchen cabinet radio cd playerRadio wave propagation could be categorized as LOS (TYPE OF Sight) and non-LOS modes. LOS is direct point-to-point propagation with no obstructions in between. Non-LOS can be indirect propagation in the absence of LOS path which includes diffraction, scattering and reflection. In the HF band (3 – 30 MHz), propagation is mainly using sky wave for long distance communications. VHF and UHF (30 MHz – 3 GHz) waves take a trip by LOS and floor bounce propagation. The SHF (3 to 30 GHz) wave utilizes strictly LOS propagation.

The purpose of propagation modeling would be to decide the likelihood of satisfactory performance of a radio program that depends upon under cabinet radio wave propagation. For RF techniques arranging, the modeling of propagation is for the purpose of RF coverage analysis. This analysis utilizes the propagation terrain and model information to predict the RF insurance location of a transmitter, the received signal strength by the end of a wireless hyperlink, the path loss from the transmitter to a range receiver, the antenna tilt angle with the transmitter, the minimum antenna height to establish Line of Sight communication route and channel impairment such as delay spread because of multi-path fading.

radio and cd player for home Propagation models for distinctive programs, terrains and environments have been created by the US government, private organizations and regular entire body such as International Telecommunications Union (ITU). These models are based on large amount of empirical information collected for the intended purpose of characterizing propagation for that application. Due to the fact propagation models are created using statistical approaches, no model will precisely fit any distinct application.

It is a good idea to employ several independent models and use the outcomes as bounds around the expected performance. Listed below are a list of mostly made use of near-earth propagation models.


The Longley-Rice model predicts long term median transmission loss over irregular terrain. It is made for frequency from 20 MHz to 20 GHz and path duration from 1 to 2000 Km. The model makes up about terrain, climate, subsoil problems and ground curvature. Longley-Rice model has two modes, point-to-point and location. The point-to-point mode uses detail terrain information and characteristics to predict path loss, whereas the certain location setting uses general information about the terrain characteristics to predict path loss.


The Okumura model is based on the measurements made in Tokyo in 1960, amongst 200 to 1920 MHz. The measured values are accustomed to decide the median industry strength and several correction factors. The correction factors involve adjustment to the amount of urbanization, terrain roughness, bottom station antenna height, mobile antenna elevation and localized obstruction. The Okumura model is particularly applicable in urban region for general insurance calculation where many obstructions and buildings exist.

Expense 231

The cost 231 Model, known as the Hata model PCS extension also, is made use of generally in most commercial RF organizing tools for mobile telephony. The insurance of the price 231 model is frequency amongst 1500 to 2000 MHz, transmitter productive antenna elevation amongst 30 to 200 m, receiver effective antenna elevation amongst 1 to ten m and hyperlink range from 1 to 20 km. The cost 231 model is restricted to application where in fact the base station antenna is above adjacent roof tops.


The Egli model is a simplified model based on empirical match of measured information to mathematical formula. Its ease of implementation tends to make it a favorite option for make use of in the first analysis. It assumes gentle rolling hill height of around 50 feet no terrain elevation information between the transmitter and receiver is needed for the model. The median path loss is adjusted for the elevation of transmit and get antenna above floor. The model includes a solitary equation for the propagation loss.


ITU terrain model is based on diffraction theory that supplies a method to predict median path loss. The model predicts path loss as a function with the height of route blockage and the first Fresnel zone for the transmission hyperlink. The model is fantastic for modeling line-of-sight hyperlink in any terrain and is wonderful for any frequency and route length. The model makes up about obstructions in the center of the communication hyperlink, hence it is actually suitable to be used both inside cities and open up fields. The model is known as valid for losses above 15 dB.

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