FAQ
Wireless modems, cables, antennas and range

Answer: Radio modem range is affected by a number of parameters such as transmit power, receiver sensitivity, bit error rate, antenna cable signal loss, antenna signal gain, signal to noise ratio, line-of-sight, Fresnel effect and multipath fading. The calculation or accurate prediction of radio range is very complex. Fortunately, enough practical experience now exists to allow reasonable estimates to be made. Data-Linc is an unquestioned expert in this area for determining how to combine the influencing factors to provide the best solution for your specific application.

2. Question: Why do some of Data-Linc's competitors quote longer ranges for similar products?

Answer: Data-Linc has traditionally specified the range of its radio modems based on field experience with real-world applications using very conservative range specification. However. In the highly competitive environment of radio modem specsmanship, many people claim very long ranges based on ideal, unrealistic conditions such as using very short cables and high gain directional antennas. If you apply the competitive “specsmanship” standard to Data-Linc’s 900Mhz radio modems they would exceed 80 miles. This however is not a realistic application for a variety of reasons so we don’t write our specs that way.

When reading radio range specifications, be sure that the numbers stated reflect real world and not ideal operating environments. Get information on the type of antennas assumed and the coax length. Obtain examples of actual systems that are at the ranges specified. A system design and quotation based on unrealistic or faulty assumptions can be very expensive!

3. Question: When needing to extend the range of a radio network, which option would be better, directional antennas or repeaters?

Answer: That is going too largely depend on why you need to extend the range. Is there a line of site problem or low received signal strength? If you're dealing with a line of site issue then repeaters are the only way to go. While adding more gain to try to "power" through the obstacle seems logical it seldom works. Putting a repeater in a location where the two "non-line of site" modems can both locate it is sound radio network planning. On the other hand, if your issue is received signal strength related I.E. a long run of coax, a high noise environment, etc..., then a directional antenna can be a good way to go.

For other questions or more information, see FAQ page for wireless data communication products or contact Data-Linc Group at (425) 882-2206 or .