APPLICATION NOTE 7113
GRE A
MERICA
, Inc. 425 Harbor Blvd. Belmont, California 94002 phone (650) 591-1400 fax (650) 591-2001
HOW FAR WILL IT GO?
An engineer's answer to an abused advertising subject.
A commonly asked question by folks new to the radio (wireless) community is
"How far will it go?"
The
answer is
"That it depends."
The direct range between two radio stations is dependent, mainly, on the antenna system. At frequencies in
the 900 MHz region, the higher the antennas are located above the ground the better. For instance, for a 32
mile range, the antennas must be 250 feet or more at each end; for 20 miles, at least 146 feet; for 10 miles, a
minimum of 83 feet. This is for rural and "flat ground" (example: The Bonneville Salt Flats)! In urban areas,
the above distances will be less, perhaps by one half. If the equipment operates in the 2.4 GHz region, the
range can be less than 30% of the 900 MHz signals.
Other "depends" include the types of antennas used, the cable feeding the antenna, ground conductivity, etc.
Other factors include the receive and transmit capability of the equipment as well as the affect of RF
pollution.
There are many claims of phenomenal range by manufacturers of low powered radio equipment, but this is
more in theory than practice. When great distances are achieved, there is usually a catch like "Yes, but the
stations are on high mountains (Pike's Peak or Mt. Everest)" or "Well, we did repeat twice to get the signal
there" or, "Gee, I forgot to mention that this is a computer model and is virtually the real thing!"
No matter what the advertising claim, the maximum radio range is dependent on geo-physical limitations. No
amount of marketing hyperbole can change that!
PLEASE CONTACT OUR EXPERT ENGINEERING STAFF AT
GRE AMERICA, INC.
TO ASSIST IN ANALYZING YOUR DISTANCE NEEDS