The Truth About 4.9 GHz for Citywide CCTV Systems

So you are going to use 4.9GHz huh!

I often ask myself this question when designing a citywide surveillance solution. My experience working with 4.9 in various deployments has not been the most pleasant. The obvious answer for me is NO, and Sometimes. Let me explain what I mean by this statement.

In comparison 4.9 GHz as well as 5 GHz frequencies have the least amount of utilization than 2.4GHz. Most private homes and small businesses use 2.4Ghz predominantly because hardware for 4.9 and 5.0Ghz was reserved for enterprise specialized hardware and applications. Over the last 5 years I have seen an increase in the use of 5 GHz and 4.9, mostly because the hardware has become more accessible. 4.9 GHz is reserved for public safety, fire and.gov (dot gov) applications so the hardware for this frequency is still out of reach of the general public.

So if the hardware is not readily accessible to everyone then shouldn’t 4.9 be pretty much open? The short answer to this question is yes, it should be but it’s not. Here is the problem with 4.9 GHz. Before I get into my explanation I need to explain the structure of the frequency. I will start with the 5 GHz first.

Lest Start with the easy stuff 5 GHz

I am going to attempt to keep this topic very modest. A frequency like 5 GHz is actually referring to a group of numbers that are in the five thousand megahertz (5000Mhz) range of the radio frequency spectrum. These numbers are known as channels. Channels on a wireless signal work pretty much the same as the general concept of channels on a TV. For example on your TV each channel takes you to a different program. You don’t know what’s on the other channels until you turn to it. It is total isolated from other channels. In Wireless the concept is the same. Channels represent a unique frequency, but just like a TV everyone has access to the same available channels.

The 5 GHz frequency band is comprised of four bands. These bands are 5.1 GHz, 5.3 GHz, 5.4 GHz and 5.8 GHz. Combined the bands have a total of 24 channels with each channel at 20 MHz bandwidth. This means that 24 channels on the 5 GHz frequency band has a bandwidth (Big Pipe) of 20MHz each. This makes the 5 GHz band very suitable for video over wireless.

But 4.9 GHz Also has 20 MHz, right?

On the other hand 4.9 GHz has very little similarities to 5 GHz. First difference is 4.9 GHz is the public safety band. Meaning it is a license band and only to be utilize by public safety agencies. You must apply on the FCC website if you are not public safety but wish to use the frequency. Here is what really confines the usability of 4.9 GHz for building an entire video wireless network. You may not understand the hertz and bertz and so forth just pay close attention to the number. Numbers don’t lie. The 4.9 GHz band is limited to 50 MHz with only 2 standard, independent channels of 20 MHz. Let’s compare this to the 5 GHz that has 24 channels at 20 MHz each. See the similarities, I think not.

So how do you deploy a citywide CCTV system using 4.9 GHz when it is limited to only 2 channels at 20 MHz? The only option is alternating your frequency, which translates to a very short game of Tic, Tac, Toe, to avoid causing yourself a complicated troubleshooting session. Eventually you will step on yourself, which is a very technical term meaning create your own interference.

OK, so should I use 4.9 in my design?

The reason 4.9 GHz, in my opinion, is not suitable for a citywide CCTV system is the lack of independent 20 MHz channels. What the FCC has done to the 4.9 GHz band is to stretch it out to allow more than two systems to utilize it. The band is fragmented in to smaller pieces. You can select to use 20 MHz (Default), 10 MHz or 5 MHz channels. The 10 MHz band allows for four (4) independent channels and the 5 MHz band allows for 10 independent channels. So what’s the problem, it appears we have plenty of channels to work with! Wrong. All it takes is for someone else, not you, to be utilizing the 20 MHz channel. Which if you recall is the full spectrum of the 10 MHz and 5 MHz channels. 4.9 GHz uses a smoking mirror technique to appear to have more available channels to operate on than it really has. The technique is referred to as channel fragmentation.

In a citywide CCTV deployment 4.9 GHz has its place. An experienced consultant, designer or integrator should have a strong background in wireless deployments and building networks. Only with experience will they know to best utilize the 4.9 GHz band.

Tornado Preparedness – The Six Keys to Safety

The US has more tornadoes than any other area on the globe. We get them in the spring, as weather changes in the fall, when summer storms hit, and as byproducts of hurricanes. Though the Midwest is known as “tornado alley,” there’s really no place in the country that’s immune. Add to this the fact that hurricanes and severe thunderstorms can produce directional winds nearly as destructive as the vortex of a twister, and it’s easy to see that we need additional preparedness info beyond “duck and cover.”

We’re going to cover the six main areas of tornado preparedness that will help you before, during, and after a tornado or heavy storm strikes. Appropriately, we’ll use the acronym S.T.O.R.M.S.:

Shelter – Strengthen your home and know where to find expedient shelter.

Time – Increase your chances of getting the early warning.

Others – Safety and protection involves the whole family and communicating with others.

Resources – You’ll need everything from immediate supply to good insurance.

Medical – Help yourself now to save the injured later.

Sweeping Up – Tips and tricks for dealing with the aftermath.

Shelter

Severe storms with driving rain, possible hail, and projectiles hurled by strong winds offer extreme dangers from which we need to protect ourselves. The best protection would be a steel-reinforced concrete safe room located in the basement of a structurally sound building. Lacking that, let’s look at a few things you should do now:

  1. Reinforce your house. There are simple things we can do to greatly strengthen our homes. Ask your local home-supply store rep about angle brackets, strapping, and techniques to install them to make your roof, walls, and connection to the foundation stronger. Also, do an internet search for “hurricane retrofit” (including quotes) to find additional instruction.
  2. Create a safe room or area within your home. The general rule of thumb is to pick an area near the center of your house and below ground if possible or at least on the lowest floor. Consider these points:

– Turn your walk-in closet into a safe area. Remove the sheetrock from walls and ceiling, add extra wall studs held in place with screws, strapping, and angle brackets, and then replace the sheetrock with one or two layers of ¾” marine plywood held in place with structural adhesive and screws. Finish and paint the walls and you’ll never know it was retrofitted. (We have plans and schematics in our preparedness manual.)

– If you live in a mobile home, your best bet for safety would be a storm cellar. One simple and relatively inexpensive way to make a storm cellar is to have a septic tank company install a clean new unit in your yard, but leave about a foot above the ground. You can build a strong cover over that and use it as an outdoor deck, or as the foundation for a storage shed.

– Some locations might reimburse you for building a safe room. Check with your tax assessor, county extension office, insurance provider, insurance commissioner, or local emergency management office.

  1. Learn the “safe points.” When a tornado strikes you might be at home, but it’s more likely you’ll be at work, out running errands, or on a trip. Learn to recognize all the locations that will provide protection. Does the building you’re in have shelters? For example, in the Denver Airport, the restrooms are designated tornado shelters. Does the building have a basement? Are you on the road? How far are you from a known safe building, or from a deep ditch?

Time In emergencies, our most important asset is time. The two best ways to gain extra time in weather emergencies are to prepare now, and to get as early a warning as possible that severe weather is heading your way. If you wait for your community’s alert sirens, you’ve waited too long.

  1. Buy a Weather Alert Radio. Not only do they warn you of inclement weather, but the system is now being tied in to the regular EAS system to warn you of other emergencies.
  2. Sign up for an alternate alert service such as the Weather Channel’s “Notify” which can be found on their website. Hint: When you get the warning, take action! Don’t do dumb things like videotaping the tornado.
  3. Learn the indicators of severe weather. The Weather Channel and others such as the National Oceanic and Atmospheric Administration (NOAA), have educational information that will teach you how to spot incoming severe weather. Some “symptoms” may include:

– A large anvil-shaped thunderhead cloud or a thick, very dark, cloud cover with a pea-soup consistency. – Hail or, in some cases, unseasonable snow.

– Green lightning (as lightning flashes behind clouds heavily laden with water).

– A sudden change in humidity, wind direction or wind speed, rain volume, or rain direction.

– A sudden change in air pressure (your ears may pop).

  1. Network with others. Sometimes our friends and coworkers are our best early warning system. Develop a phone tree or at least a general agreement among friends and relatives that you’ll warn each other about dangers in the area.

Others There are two sets of “others” you might deal with in concert with a severe storm. One is your family and the other is first responders. Communicate with your family both now – to prepare for a tornado – and later in the event a tornado watch or warning is given. You also may need to communicate with first responders if you experience injury or certain types of property damage that requires official assistance. Consider:

  1. Tornado drills. Emergency reactions are worth practicing. Have your family practice getting into the safe room and into a safe position (“duck and cover”) within 30 seconds or less.
  2. Protect your pets. On warning of severe weather, round up your pets, put them on leads or in carriers, and take them to your safe area. If your house is damaged in the storm your pets are more protected and easier to care for afterward. Hint: You can train your pets to head to the safe room on command. Your vet can give you some training pointers.
  3. Communication and signaling may be vitally important if your home is damaged and/or someone sustains injury during a tornado. For example, though everyone might be uninjured, you may be trapped in the debris that was once your home and need someone to dig you out. In addition to your house phone and cell phone, have backup options like a hand-held two-way radio, and something that can make a loud noise such as an air-horn. Also, make sure your neighbors know you have a safe room in the house, or storm cellar in your yard. They can tell authorities where to look if no one has heard from you.

Resources In a disaster, you’ll need goods, gear, or services to help you deal with the event and then recover afterward. Make sure you have adequately covered each of the following areas:

  1. Make sure your insurance policy covers all types of natural disaster including water damage from rain or flood since many policies have strict exclusions. Also, make sure your policy will provide for the costs of temporary lodging and the full replacement value for your property and possessions.
  2. Keep your isolation and evacuation supplies together in a protected spot where you can access them immediately, or where they’ll be protected if your home is damaged while you’re away.
  3. Make a list of services you might need after a tornado, such as cleanup and repair services or temporary lodging. Look through your phone book to find services like tree-cutting and debris removal, structural home repairs, automotive repairs, lodging, etc. Write their contact information down and keep it with your emergency kits so you can call these services immediately after a disaster to get your name on their lists.

Medical We’re hoping that all the advice above has kept you safe in the event of a tornado. However, we know things do happen and people get hurt. Cover the following, just in case:

  1. First aid training is important for every family regardless of the threat, so learn the basics of general first aid and CPR. Next, talk with your doctor about first aid measures for specific ailments. For example, if someone in your family has Asthma and they have an attack, what are some things you can do to care for them if you can’t immediately get to their inhaler or medication?
  2. First aid kits are a must and families should have several and not just one. The main kit should be kept in the home, but smaller kits should be kept in each automobile and at your workplace.
  3. Copies of medical information should be kept at home. After a destructive event there’s no guarantee your family doctor will be available or that the hospital’s computers will be functional. In case of injury, medical practitioners will need to know a general medical history of the injured. Keep a list of ailments, conditions, special medical needs, and current medications of each family member (including pets). Remember, even though you’re the head of household and you know all that information, you may be injured and unable to communicate.

Sweeping Up All destructive events have at least one thing in common; they’re going to create quite a mess. Here are a few tips to help you stay safe while cleaning up:

  1. Though you might think the power is completely out, stay away from downed power lines.
  2. Stay alert to the hissing sound of a broken gas line or the smell of gas.
  3. Dress for the weather, but still dress to protect. Wear sturdy shoes or boots (and watch out for boards with nails), a hat and sunscreen, insect repellant, and heavy work gloves. The hospitals will be too full of major injuries to deal with the minor injuries you could have prevented.
  4. Physical labor after a stressful event can be quite taxing. Drink plenty of fluids, eat regularly, and take periodic breaks.
  5. Here is where you’d need your list of professional cleanup services. Call as soon as possible.
  6. In the case of total destruction, your property itself will be a trash pile. Therefore, use your main trashcan as a receptacle for the items you want to salvage. Label it accordingly so no one throws away its contents. Hint: Take photographs or video of all the damage for insurance purposes.
  7. It’s possible that your valued possessions might be strewn about the neighborhood. It’ll be easier to have things returned if your name is written or engraved on them. If you don’t want to use your name, use a unique identifier such as the first phone number you can remember from childhood. Hint: Never use your Social Security Number.

Though this article is longer than average, there is still no way we can pass along all the helpful hints and tips that will keep you safe in an emergency and help you recover afterward. Do what you can with the information presented, and continue your education on your own. The steps you take to protect yourself against tornadoes will help protect you and yours during any number of other disaster preparedness scenarios. Stay safe!

Safety Equipment – A Buyer’s Guide

When your company is looking for safety equipment, there are many factors to consider before placing an order. Safety equipment includes head, respiratory, and full-body equipment. It also includes emergency equipment. The big question is: How will you know what you need to purchase? The answer is simple. Before you purchase safety equipment, you need to put together a list of what each employee will need to be safe on the job. Below are a few examples of safety equipment products and ways to decide what manufacturer is right for you.

Earplugs are one of the big sellers when it comes to safety equipment. Earplugs can be purchased as disposable plugs or as reusable plugs. Disposable earplugs are manufactured out of smooth, non-allergenic material that conforms quickly and comfortably to the shape of the ear canal. On the other hand, reusable earplugs are washable, but are flexible when adjusting to the ear canal. Both disposable and reusable earplugs are comfortable for most employees and are extremely lightweight.

Earmuffs are another type of safety equipment on the market today. Safety product manufacturers provide a wide variety and range of earmuffs. Some earmuffs allow a person to hear well enough to communicate, while other earmuffs provide complete sound protection. Some earmuffs have steel headbands, while others have plastic headbands. Some earmuffs are able to connect to a safety helmet. You can even purchase earmuffs that wrap around your neck. Common features that all earmuffs have are soft foamed cushions, superior protection in the most demanding circumstances, and comfort.

Safety glasses are another form of safety equipment. Choosing a pair of safety glasses is more difficult than choosing a pair of earplugs or earmuffs. But if you take your time and critique the several different features involved, you will find the right pair. First, you must decide what type of safety glasses are needed for your particular job environment. You need to decide whether safety glasses need vented channels, and what type of lens material they should be crafted from. You must choose between panoramic, polycarbonate, or prescription safety glasses. The size of the safety glasses also makes a big difference. This is because if they are large enough, they can be worn over regular prescription glasses. Most safety glasses have the standard features of anti-fog and scratch resistant lenses.

Safety equipment can be purchased in many stores including Lowe’s, Home Depot, Wal-Mart, and K-Mart. It can also be found on many sites on the Internet.