Antenna Installation & Setup
Standard Omni Antennas
We ship all our Wireless Control Systems with standard Dipole Omni-directional Antennas. The standard antennas allow you to obtain the following system results.
Estimated System Distance with Included Standard Antennas
|2.4 GHz||5 dbi||
Indoor/Urban: 100ft., Clear Line-of-Site: 600ft.
|900 Mhz||7 dbi||
Indoor/Urban: 1000ft., Clear Line-of-Site: 3 Miles
Dipole Omni-directional Antennas
Dipole antennas are the most common type of antenna used and are omni-directional, propagating radio frequency (RF) energy 360 degrees in the horizontal plane. These devices are constructed to be resonant at a half or quarter wavelength of the frequency being applied. This antenna can be as simple as two pieces of wire cut to the proper length or can be encapsulated as shown in the illustration; this configuration is commonly referred to as a “rubber ducky” antenna. The dipole is used in many enterprise and industrial applications.
Optional Yagi Antennas
Optional long distance Yagi Antennas are available that allow maximum system operation.
Estimated System Distance with Optional Yagi Antennas
|Model No.||Freq.||Gain||Operating Distance|
|DRWC-24-LRANT||2.4 GHz||11 dbi||
Clear Line-of-Site: 1 Mile
|DRWC-900-LRANT||900 MHz||9 dbi||
Clear Line-of-Site: 6 Miles
|DRWC-900-LRANT-XL||900 MHz||13 dbi||
Clear Line-of-Site: 9 Miles
A Yagi antenna uses several elements to form a directional array. A single driven element, typically a dipole, propagates RF energy; elements placed immediately in front of and behind the driven element re-radiate RF energy in phase and out of phase, enhancing and retarding the signal, respectively. The elements are called parasitic elements; the element behind the driven element is called the reflector, while the elements in front of the driven element are called directors. Yagi antennas have beam widths in the range of 30 to 80 degrees and can provide well in excess of 10 dBi passive gain.
Antenna Installation & Positioning
Proper antenna installation and positioning is important and will allow you to achieve maximum performance and distance between your transmitter and receiver unit. This will reduce the possibility of a lost connection during operation. Antenna Basics When installing your transmitter and receiver it is important to install both units in such a way as to optimize the position of both antennas within what’s known as the “Fresnel Zone”. A Fresnel Zone can be thought of as a football shaped invisible tunnel between two antennas that provides an optimum path for the RF signals between your transmitter and receiver.
The Fresnel Zone
Fresnel created a calculation on how out of phase the wave would be between the transmitter and the receiver. The Fresnel zone is a 3-D cylindrical ellipse shape (like a football) and is made up of multiple zones, Zone 1 being the strongest area for signal strength, Zone 2 being the weaker, Zone 3 being weaker still and so on. There are many Fresnel zones, but only the first 3 have the any major effects on signal strength. Phase cancelling effect in even numbered zones have the maximum effect, while in zones with odd numbers can have a positive effect to signal strength.
So, to maximize the signal strength at the receiver, you want to minimize the any out of phase signals from reaching the receiving end by making sure the strongest signals do not bump into any obstacles. The general rule of thumb is that the 1st Fresnel zone must be 60% clear of obstruction from the center line of sight to the outer boundary of the 1st Fresnel zone to maintain a good connection. To achieve maximum distance, the path in which the RF signals travel must be free of all obstructions. Obstacles in the path will decrease the transmit/receive distance. Also, if the antennas are mounted too low to the ground, most of the Fresnel zone ends up being obstructed by the earth resulting in significant reduction in transmit/receive distance. Your antennas should be mounted as high off the ground as possible. A minimum of at least 8-9 feet is recommended. It is important to understand that your application environment may change over time due to new equipment, buildings or other RF equipment being installed. There can also be change within your building such as new construction, etc. If new obstacles are added between your switch transmitter and relay receiver you may need to move and re position your antennas.
Installation of Standard Omni-directional Antennas
Connecting Your Antennas
Your control system has been shipped to you with standard antennas. In some difficult installations you may wish to place a remote antenna farther away to maximize transmission range to the receiver. A remote antenna kit option can be ordered that include an antenna extension cable and antenna mounting bracket. Please note that very long antenna extension cables will always add loss to the signal strength. The longer the cable the more signal will be lost over the cable. Because of this the length of the cable should be kept as short as possible. Use of any other antenna then what’s supplied with your system or what’s available as an option may void FCC and IC regulatory compliance.
Antenna Placement (Standard Omni Antennas)
Vertical Antenna Placement
If the antenna for one of your units is mounted in a vertical position you should mount the antenna of the opposing unit in the same polarization.
Horizontal Antenna Placement If the antenna for one of your units is mounted in a horizontal position you should mount the antenna of the opposing unit in the same polarization.
Installation of Optional Yagi Antennas
Horizontal Antenna Placement
The optional long-distance Yagi antennas must be mounted in the horizontal position as shown in the picture below. Antennas should be mounted 7-8 feet off the ground or higher and pointed at each other. If one is mounted on a hill the unit on the hill should be pointed in a down hill angle towards the other antenna. The antenna in the valley should be angled up pointing towards the antenna on the hill. Do not point either antenna in a straight up vertical position pointing at the sky, or the system will not make a connection.