Interference Study
Interference Study
Although the unlicensed spectrum
offers the benefit of no licensing fees, users pay a penalty in terms of
interference. There are no restrictions on the types of devices that operate in
these bands, provided that they all conform to a common set of rules. Although
the 5-GHz band is less crowded than the 2.4-GHz band today, over time the 5-GHz
band will likely become equally crowded with more and more interference-causing
devices.
The Industrial, Scientific, and
Medical (ISM) frequencies can contain emissions from microwave ovens,
heaters, plywood laminators, medical diathermy, and other noncommunication
devices. Although most of these types of devices usually pose no threats of
interference to bridge links (because they are low-power, indoor devices), the
engineer must be aware that the possibility exists of some industrial high-power
system (such as a 10-kilowatt industrial oven next door) that wipes out any
attempted communications use of that band. Equipment operating in this type of
environment is subject to FCC rules and regulations as well.
Amateur radio operators are also licensed to use parts of the
bands in which bridge products are designed to be used. Although not many
amateurs use these bands, a few full-time (on the air continually)
point-to-point amateur microwave links operate in this band.
There is also the possibility of interference from other data
systems in the same bands. In any case, it is necessary to do an interference
analysis using a spectrum analyzer to make sure you have an interference-free
radio link. |
|
502 times read
|
|
|
|