Specifications

Rockwell Automation Publication AG-SG001G-EN-P - April 2015 29
Choosing a Telemetry Network Chapter 2
Disadvantages
• Transmission is limited to a line-of-sight, for example, you cannot transmit
through mountains. The signal can experience distortion and interference.
Also, atmospheric conditions such as rain, snow, or fog can affect the
signal.
• Most microwave link frequencies are allocated and regulated by the
Federal Communications Commission (FCC). In urban areas, fewer data-
transmission frequencies are available.
• You can incur large initial expense for equipment.
Equipment Required
• Transmitters
• Receivers
• Parabolic dish antennas
• Repeaters are needed to transmit long distances over hills or mountains
VHF/UHF Radio
VHF/UHF radio is a high-frequency electromagnetic, wave transmission. Radio
transmitters generate the signal and a special antenna receives it.
Advantages/Capabilities
• The media links geographically-remote areas that are not accessible by
phone lines.
• A constant connection exists.
• Transmissions can occur over rough terrain and over distances of less than
30 miles.
• You incur no monthly service fee because you own the equipment. The
only expenses are operation and maintenance costs.
• Minimal transmission delay times exist.
Radio
Modem
Radio
Modem