Remember a few years ago when the whole world was going to crash because of two digits? Armies were put on notice for riot control, enthusiasts stockpiled food and fuel, people purchased electrical generators in record numbers, and the sale of guns and rifles reached new highs. That’s how I feel from time to time about the whole digital revolution, and I’m supposed to be some sort of expert!
So much has happened during the past 12 months that we have had to learn a whole new language – or perhaps I should say, we have had to reapply a whole new meaning to much of our old language.
Take wireless, for instance. To me, when someone was talking about wireless, I thought they were talking about sending the video signal from the camera to a recorder or monitor somewhere via a simple transmitter and/or some format of microwave system. Or it could be we were speaking about transmitting a group of images from multiple cameras using various multiplexers and long-range transmission systems.
These were reasonable assumptions since it was what we in the CCTV industry called wireless the past 25 years. However, the new digital revolution is turning wireless into so much more. Get ready for the race as the computer and the security industries merge even further and work out the language similarities and differences through time and patience. The result will be undreamed of video applications and solutions.
Strict Regulations, Cost Held Back Microwave Transmission
The CCTV industry started with microwave systems. About 25 years ago, these systems were the only wireless we knew. It’s a simple enough idea. Take the electronic video, audio and/or data signal and convert them into high frequency RF signals (somewhere between 21GHz-23GHz).
Several things held microwave systems of old in check, not the least of which was licensing restrictions. A fairly extensive, 25- to 40-page application, full-site survey, area survey and more had to be done before the client could even be sold a system. The initial outlay of cash ranged between $250-$1,500 without a single piece of equipment being purchased or approved.
Once the system was up and running, the results were incredible, delivering high-resolution, full-frame rate, perfect pictures. From time to time, there were problems with the transmission and reception. Overall, however, microwave systems were hot.
Another big factor of the old wireless systems was cost, with a small, half-mile transmission system starting at $10,000. To top it off, one-quarter-mile was the minimum distance allowed or available. In other words, sending a single camera less than a half-mile was a very expensive proposition. We have come a long way since then.
Microwave Becomes Wireless; Technology Rises as Prices Drop
The following four steps have put microwave, or rather wireless, systems back on the block.
Step 1 – Walk away from all the associated, negative vibes of the past. Change the language and start to refer to our old, expensive and cumbersome friend microwave as wireless.
Step 2 – Get rid of the heavy paperwork and licensing requirements by lowering the frequency base of the average transmission/reception system to anywhere between 2.4GHz-5.8GHz and ensure adherence to FCC Part 15 regulations (designed to ensure no device dominates the spectrum).
Step 3 – Develop enough technology to make these systems applicable to sending a video signal 10 feet to 10,000 miles.
Step 4 – Get the price down to make it all affordable.
However, just because wireless transmission is alive and well in its new and well-developed realm doesn’t mean there are no requirements and/or negative associations. There is still a fair amount of work and considerations to the design and implementation of a well-tuned wireless system.
Pay Attention to Distance, Obstacles During System Design
Granted, if you are only interested in sending a video signal across the interior dome of an old, historic government building, you are probably only looking at 10-15 minutes of work to align and verify signal strength (once installed, of course). But, if you plan to run a quarter-mile or 10 miles, you had better pay careful attention to the technical staff of a qualified wireless manufacturer.
Stick to these three simple rules of thumb:
1. Wireless (microwave) is omnidirectional, meaning, in simplest terms, it is a line-of-sight device. For this reason, long-range systems have repeating stations at various points. Consequently, repeaters are used to compensate for the curvature of the Earth across long distances and to go around buildings and such in city environments.
2. Because these microwaves are of such a high frequency level, they are literally absorbed by moisture in the air. Therefore, wireless systems are designed using specific distances allowing for this natural tendency. This natural absorption of the signals is the principle that allows us to use wireless systems in multiple locations without interference or cross talk. Distances for wireless transmission range from 50 feet to hundreds of miles with proper repeater systems.
If microwave signals were like other forms of radio waves, one system’s signal would bounce around the world and we would be restricted on how many systems or signals we could use. Although microwaves do not bounce around the world, competing systems installed in the same area can cause problems and/or overrides. This is why a site or area survey is always recommended.
3. Another reason for the line-of-sight problem with the wireless system is that the microwaves themselves are so weak they cannot reliably penetrate buildings, cars and trucks, trees, or other items of mass. Therefore, such obstacles need to be noted and addressed in the initial area or application review.
Transmitters Reduced in Size While Enhanced in Capabilities
In the mid-1980s, wireless transmissions took a new place and expanded the name. Small RF transmission systems were introduced that gave us the ability to send black-and-white images as far as a quarter-mile – half-mile if unobstructed.
A few years later, color became possible as well. The reason for the delay between black-and-white and color transmissions came down to an old and formidable challenge of the video industry – bandwidth, the factor that determines the resolution or quality of image.
The amount of bandwidth is what slows down transmissions and/or detracts from the number of images we are able to transmit per second. These new wireless systems were not omnidirectional. They worked like radio transmitters and sent their weak signals in all directions simultaneously. However, like the microwave, all sorts of things – such as walls, floors, ceilings and steel supports – could cause the loss or dampening of the signal.
Broad boasts of the marketers of these new wireless systems gave the buyer the impression they could tune into the video signal from anywhere within a half-mile or so. However, reality set in after the first couple of efforts. Such transmitters have, during the past 20 years, advanced in both diminishment of size and improvement of transmission capabilities.
The popularity of these systems has increased so much outside the security world that the average individual on the street best knows these wireless camera systems as baby cams. What’s more, you can’t go on the Internet without being bombarded by tiny wireless cameras for home use. Yes, for $99.95 you too can spy on your family, friends or neighbors!
The major problem with these transmitters, besides the obvious limitations of distance, is privacy. There is none and there is little that can be done about it. Anyone tuning in on the appropriate frequency (very often a television channel) can see what you see.
The second biggest proble
