User Guide: Technical Reference
SECTION 2
ioLink 4
SYSTEM COMPONENTS
PRELIMINARY
Customer Support (202) 333-7031
2-6
2.5 Antenna Description
The antenna is usually a grid or parabolic-dish type and normally is no larger than two feet in diameter.
For short distances (2 miles or less) Yagi antennas may be used. The antenna chosen can have linear,
elliptical, or circular polarization. Each antenna can be mounted on a roof, a tower, or positioned inside a
non-metalized glass window and must have a radio line-of-sight (LOS) link with the receiving antenna.
The type of antenna required is based on the distance of the link, number of co-located links and region.
Please consult
ioWave
, or
ioWave
qualified vendors, when selecting the antennas.
2.6
Antenna Selection and Consideration
2.6.1 Size
The distance the signal must travel from one end of the link to the other is the primary factor in
determining the size of the antenna. In addition, the environment in which you place the antennas
needs to be considered in selecting the antenna size.
The gain of the antenna is usually proportional to the size of the antenna. Antenna gain is a measure
of the amount of focusing of a signal the antenna achieves upon transmission or reception.
ioWave
’s
Systems Integration team can calculate the required antenna gain after completing a site survey and
path analysis for a particular link.
The larger the antenna, the narrower its beam width and the higher the resulting gain. Narrower beam
widths increase the possibility of making a successful link, especially when there are possible
obstructions and interference. If you are placing an antenna in an urban environment, you may need
a larger antenna to transmit and receive signals than you would in a rural environment even if the
distance between antennas is the same. This is due to urban environments usually having more
obstructions and interference.
