10 Tips to Reliable Wireless Systems
10. Place the client on a routine maintenance inspection plan
To sustain the proper operation of your customer’s short-range wireless alarm system, encourage them to sign a routine maintenance agreement. In most situations, service every 12 months is sufficient to warrant operability. In high-risk environments, every six months may be more appropriate.
Of special concern to security dealers are the changes that may have taken place within the immediate environment since the installation or last inspection. This includes the introduction of large metallic appliances and furniture of any kind that can attenuate signals that travel through or near to them.
Another concern that service technicians should be aware of relates to new sources of high-power RF energy in the environment surrounding the building. Possible sources include high-power transmitters typical of amateur radio operators and citizen band operators that push hundreds of watts of RF power. Other sources include microwave towers, large electric motors, and certain induction-type industrial equipment, as is used in smelting plants and large steel mills.
Finding Sources of Potential RF Interference
The longer a technician works in this business, the better he or she understands general construction practices, which can help determine possible sources of RF interference. “I know construction well enough that I’m able to determine what’s behind a wall by just looking at it,” says Nick Markowitz,owner of Markowitz Electric Protection of Verona, Pa. One method that can help security dealers determine the presence of stray RF interference is the use of a tool that analyzes the electromagnetic spectrum for nearby sources. Such equipment, however, is usually out of the price range of most security dealers.There is an alternative, however.
“The thing I do is use an AM radio to detect possible sources of RF interference,” says Markowitz. Although the frequency of the alarm system is not the same as the AM receiver, he says if there is something present that can interfere with the radio, then you can bet it will interfere with the wireless alarm system as well.
Another way to determine whether there are potential problems is to bring a working wireless system with you and test it in the building.
Some systems actually provide an indication of the RF power of each transmitter reaching the receiver. This test is usually performed using an English language keypad. Equipped with this information, you can make a more informed decision on where to place the radio receiver.
Effects of Wave Polarization on System Reliability
There are two types of radio wave transmissions – vertical and horizontal polarization. Polarization effectively indicates the way in which the radio wave propagates from a transmitting antenna to a receiving antenna. Whereas a horizontal antenna propagates RF energy one direction only, either front or back, a vertical antenna emanates radio energy 360° in all directions.
There are two ways to align the transmitter antenna with the receiving antenna. The first is to reposition the transmitter opposite its current position and measure the result. In other words, if the transmitter is physically positioned in a vertical manner, turn it sideways and then test the system.
The second way to deal with antenna polarization is to use a receiver equipped with two antennas – one vertical and the other horizontal (some come with two vertical antennas).This method also ensures reception when the wavelength is such that one of the receiving antennas is positioned at the null of a transmitter’s radio wave.
If you enjoyed this article and want to receive more valuable industry content like this, click here to sign up for our FREE digital newsletters!
Related Content
Security Is Our Business, Too
For professionals who recommend, buy and install all types of electronic security equipment, a free subscription to Commercial Integrator + Security Sales & Integration is like having a consultant on call. You’ll find an ideal balance of technology and business coverage, with installation tips and techniques for products and updates on how to add to your bottom line.
A FREE subscription to the top resource for security and integration industry will prove to be invaluable.
