900 Mhz: The Wireless Workhorse

All wireless technologies and frequencies are not created equal.  Most of us have been programmed that bigger is always better, so when it comes to looking at wireless radios you think, why wouldn’t 2.4 or 5.8 GHz be better then 900 MHz.  This isn’t always the case with wireless spectrums.  If we all had businesses that operated out in wide-open fields, this might be true, but most of us don’t operate in wide-open fields.  There are buildings, trees, and other obstacles that get in the way of wireless utopia.   Since most of us do not live in wireless utopias, we at Grid Connect feel that for most applications 900 MHz is the most versatile and best frequency for radios to use.

The lower frequency radio waves of 900 MHz radios provide greater penetration through walls, trees and other obstacles, making it optimal for most non-line-of-sight applications.  A typical AW900xTR Radio using high powered AW-15 15dbi antenna can go distances of up to 1500 feet with buildings and/or trees in the way.  In an indoor scenario, an AW900itr Radio can go similar distances through up to 10 building walls.

900 MHz radios also have the ability to diffract around/over obstacles like buildings or trees.  The radio signal must, however, be given enough room to spread out.    As we like to explain to customers, the radio needs a certain amount of “runway”  (we usually recommend 25-50 feet or more) for the signal to fan out into a “football shape” where it is widest in the center and comes together on the sending and receiving ends. With an AW900xtr Radio and AW-15 antennas under ideal circumstances with a 10° Angle of attack, radios can reach up to 1 Mile, at a 5° Angle up to 5 Miles, and with a 1° angle up to 30 Miles.

The biggest weakness of the 900 MHz frequency is the limited amount of unlicensed bandwidth in the spectrum.  There is only 26MHz of available spectrum, where other frequencies have as much as 3 times the amount of available spectrum.  In some cases, this will result in a lot of noise from other products operating in this spectrum range.   Additionally, 900MHz is not an open public spectrum in most countries outside of North America.

In addition to 900 MHz there are other frequencies available that have unique strengths.

2.4 GHz is a universal band that is unlicensed and accepted throughout the world.   WiFi (802.11), Zigbee and Bluetooth live in this spectrum, and so even though it is wider than the 900MHz band, it has more competition from other wireless technologies.

4.9 GHz is a licensed band ideal for public safety applications and is often used in line-of-sight police, fire, and other municipal network communications.

5.8 GHz offers higher data rates and line-of-sight communications and is ideally suited for long-range wireless backhaul.  With its higher data rates, 5.8 GHz addresses the needs of higher bandwidth IP-based surveillance cameras.

Grid Connect offers a wide range of 900 MHz Ethernet Bridges and other 900 MHz Radios (point-to-point and point-to-multipoint) and for long distance RS232/485 Serial networks as well.    We carry both outdoor NEMA4 enclosed radios and indoor radios.  Our offerings include the AW900x, a simple point-to-point plug & play outdoor wireless radio.  We also offer the newer AW900xTR, a point-to-multipoint radio, which now includes a 900 MHz spectrum analyzer allowing you to diagnose interference issues on the fly.  Indoors, we have the AW900iTR offering a simple easy to use interface with point-to-multipoint capabilities.  The newer xTR and iTR radios can be monitored and configured using their built in web page, which is great for when radios are mounted outside or in tucked away locations.   We also offer a wide range of antennas for various applications as well as other radio accessories.

Adam Justice is the Vice President and General manager of Grid Connect, a manufacturer and distributor of awesome networking products based in Naperville, IL. You can find him on Google+ and Twitter.

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