Brrr… It’s Cold Out There!

One of the most important criteria for an outdoor camera is the ability to work over extremes of environmental conditions. In the United States, the commonly accepted operational outdoor temperature range for traffic or security applications is about -35° C (-31° F) to +75° C (+167° F). The Sidewinder series of cameras (and all of the other cameras manufactured by WTI) are designed to work over this extreme temperature range.

The Sidewinder camera incorporates several special features that allow it to operate at extremely low temperatures. Multiple temperature sensors distributed throughout the camera ensure that power is efficiently directed to the areas that require it, keeping all camera components operating within the optimum temperature range.

The camera tube section of the Sidewinder incorporates a solid-state temperature sensor to monitor the internal temperature of the tube and control the operation of a 10 Watt resistive heater that keeps the temperature of the video sensor and zoom lens optical assembly in the optimum range for best performance.



The camera tube faceplate assembly incorporates another solid-state temperature sensor that monitors the outside environmental temperature and controls the amount of power applied through a 3.5 Watt pulse width modulated power amplifier to the Indium-Tin Oxide (ITO) electrical coating on the inside of the window glass. This keeps the window glass from accumulating frost, or from becoming fogged up in high humidity conditions. By applying the power directly to the ITO coating on the window glass, a significant reduction can be made to the amount of power required to keep the glass clear of any ice or fog. This window glass temperature control is a feature found in all of the cameras manufactured by WTI.



A third temperature sensor within the main body of the Sidewinder monitors the temperature of the motor assemblies and electronics. In order to maintain the high pointing accuracy specification of the Sidewinder, the motor drive assemblies must be kept from changing temperature too much. When the temperature within the housing drops too low, the idling current in the precision stepper motors is increased, to gently warm the motor assemblies back up to optimum operating temperature and to help regulate the temperature of the drive electronics.

The combined operation of the multiple temperature sensors and multiple heating mechanisms allows the Sidewinder camera to come up to operating temperature in approximately 7 minutes after being shut off in -35° C temperatures for several hours.

Operation at the +75° C end of the temperature range is just as important as the low temperature performance. While the highest air temperature ever recorded on Earth was less than +60° C (+136° F in Libya on September 13th, 1922), all cameras manufactured by WTI are tested to the more demanding +75° C temperature standard required for traffic control cabinet products. Several features of the cameras contribute to reliable operation at elevated temperatures. All of the cameras are powder coated gloss white to reflect energy from the sun and help keep the cameras cool. All of the electronic and mechanical components are selected to be compatible with the extreme temperature range demands of the cameras. All of the electronic and mechanical components are designed to be energy efficient to keep self-heating to a minimum.

It takes careful monitoring and control of the environment inside the camera to allow the best possible performance of the camera, no matter how extreme the outside conditions may be.

~Dale Roche, Director of Engineering


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WTI (Wireless Technology, Inc.)

Video Surveillance Products Dedicated to the Broadcast, Global Security and Transportation Markets!

http://www.gotowti.com/ ● http://www.wirelesstech.com/

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Considering “Repeatability” of P/T/Z Cameras

Yes… another detail to consider when reviewing P/T/Z cameras; “Repeatability”. This may be of little concern when the intended P/T/Z camera application uses very low or no zoom within the presets of a tour. High end P/T/Z cameras with large optical zoom ranges tend to (and should) have higher repeatability ratings than other cameras. WHY?

First…
Repeatability, with regard to a P/T/Z camera specification, can be defined as the accuracy within which the camera position of the pan AND tilt axes are able to recall the previously set (aka: preset) position. Repeatability is typically given in degrees: 0.05°, 0.08°, 0.25°, etc.

Second…
The numbers given for repeatability are degree based. In effect, the repeatability specification references the ability of the camera to return to an exact position specified within the circular rotation of an axis. In the case of P/T/Z cameras… both the pan and tilt axes.

With these definitions in mind…
In a wide angle shot (with zoom at or near zero), any factor of repeatability found in today’s P/T/Z cameras is likely negligible. The image shift on either pan and/or tilt of even 0.25° when viewed after recalling a preset position will be very hard to notice.

The difference in repeatability becomes noticeable when a zoom setting has been associated with the preset position. A high zoom setting amplifies the image shift that occurs when the preset is recalled. The 0.25° image shift now becomes visible.

Repeatability can have a distinct impact on the resulting video image provided by the camera for real-time viewing as well as for what may be getting recorded into a DVR/NVR. The positioning of the viewable image provided by the recall of a preset should allow for variations due to the camera repeatability. This means that the user should test the presets several times to ensure the viewable image will still provide the desired video data even if the image has shifted.

Unrelated to the repeatability of the camera itself, yet related to the repeatability of image acquisition from a preset… stability of the camera mount location. The characteristics of the camera mount should be considered when establishing presets and expected image shifts. Mounting to the top of a pole is very common along highways, intersections, etc. Consider the suns effect on the pole material throughout the course of a day. One side of the pole is exposed to the sun during the morning hours while the other side is not; one side “hot” and one side “cold”. The material expansion coefficient, coupled with the height of the pole, can create an angular shift much greater than 0.05°. This angular shift may reverse throughout the course of the day as the sun changes position. Oh yes… and don’t forget wind!

In general, every P/T/Z camera has a number that specifies repeatability. A lower number will tend to indicate a higher quality of manufacturing, and is more likely to be associated with units incorporating a higher optical zoom or specialty video (thermal) capability.

~ David Scales, Chief Technology Officer


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WTI (Wireless Technology, Inc.)

Video Surveillance Products Dedicated to the Broadcast, Global Security and Transportation Markets!

http://www.gotowti.com/ ● http://www.wirelesstech.com/

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A Farewell to Analog TV

There goes the front and back porch!

At midnight on Thursday, all television signals will switch from an analog to digital signal transmission.

(RCA Studio Camera - Era 1950s)

So why exactly is this changeover happening?

“Congress mandated the date and the switch,” said Federal Communications Commission spokeswoman Mary Diamond. “The benefits of the switch to digital are that the valuable spectrum that becomes available will be able to be used by public safety groups. Your local police and fire department, as well as wireless innovations and consumers, will be able to have a better picture and sound.

“Literally, the spectrum when you convert from analog to digital, you’re compressing what you’re using. Digital takes up less space.”

I guess this is progress! The FCC mentions public safety groups….and less space. What the FCC is really doing is putting up a sign that says: “Spectrum for Sale” as we have foreclosed on the previous Analog owners! I know sour grapes! However Digital TV has a lot of advantages over analog TV, the most significant being that digital TV channels take up less bandwidth (and the bandwidth needs are continuously variable, and this of course has a corresponding cost in image quality depending on the level of compression). This means that digital broadcasters can provide more digital TV channels in the same space and provide other non-television services such as multimedia or interactivity. Digital TV also permits special services such as electronic program guides and multi language capabilities, spoken or subtitled. The sale of non-television services will also insure an additional revenue source.

(Walter Cronkite broadcasting from the first ENG vehicle!)

Back before Black and White TV everybody got their news from radio, newspapers, and the newsreels that were shown in the movie houses. Radio was big and getting even bigger, reaching audiences in the tens of millions. TV had almost zero audience and very few advertisers. At this point in time, TV looked like it did not even have a future! Then out of nowhere appeared Walter Cronkite, a veteran war correspondent and former Moscow bureau chief for the United Press. He started broadcasting in 1950 and was the first reporter to be assigned exclusively to television at CBS’s Washington bureau and the rest is history!

Saying good bye to analog television makes me sad but when I turn on my HDTV flat screen at home, I have to admit it is fantastic and definitely a step up from my old CRT.

(Mike Wallace going "barefoot" with an early portable set up - the batteries were heavy, real heavy!)

I have to wonder when the HDTV signals cease being transmitted what will replace them!

~ Dan Fancher, President/C.E.O.

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WTI (Wireless Technology, Inc.)

Video Surveillance Products Dedicated to the Broadcast, Global Security and Transportation Markets!

http://www.gotowti.com/ ● http://www.wirelesstech.com/

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Digital Television; are you ready for the switch?

Digital Television (DTV) is the sending and receiving of moving images and sound by discrete (digital) signals, in contrast to the analog signals used by analog TV.

While the majority of the viewers of over-the-air broadcasting in the USA watch full-power stations (which number about 1800), there are three other categories of TV stations in the USA: low-power stations, class A station and TV translator stations. There is presently no deadline for these stations, about 7100 in number, to convert to an all digital signal.

The switch from analog to digital broadcast television is referred to as the digital TV (DTV) transition. In 1996, Congress authorized the distribution of an additional broadcast channel to each broadcast TV station so that they could start a digital broadcast channel while simultaneously continuing their analog broadcast channel. Later, Congress has set June 12, 2009 as the final date that full-power television stations can broadcast in analog only. Your local broadcasters may make the transition before then, and many already have.

Under the law, on Feb. 17, some full-power broadcast television stations in the United States stopped broadcasting on analog airwaves and began broadcasting only in digital. The remaining stations will most likely stop broadcasting analog sometime between April 16 and June 12.

Because Congress mandated that the last day for full-power television stations to broadcast in analog would be June 12, 2009, all over-the-air TV broadcasts will be in digital after that date. If you have any televisions that receive free over-the-air television programming (with a roof-top antenna or "rabbit ears" on the TV), the type of TV you own is very important. A digital television (a TV with an internal digital tuner) will allow you to continue to watch free over-the-air programming. However, if you have an analog television, you will need a digital-to-analog converter box to continue to watch broadcast television on that set. This converter box will also enable you to see any additional multicast programming that your local stations are offering. Do not wait until June to prepare. Many stations may be converting early and you need to be ready beforehand.

To help consumers with the DTV transition, the Government established the Digital-to-Analog Converter Box Coupon Program. The National Telecommunications and Information Administration (NTIA), a part of the Department of Commerce, administers this program. Every U.S. household is eligible to receive up to two coupons, worth $40 each, toward the purchase of eligible digital-to-analog converter boxes. The coupons may only be used for eligible converter boxes sold at participating consumer electronics retailers, and the coupons must be used at the time of purchase. Digital-to-analog converter boxes sell for $40 to $70 each.

As of March 1, 2007, all television receivers shipped in interstate commerce or imported into the United States must contain a digital tuner. Also, effective May 25, 2007, the Commission required sellers of television receiving equipment that does not include a digital tuner to disclose at the point-of-sale that these devices include only an analog tuner, and therefore will require a digital-to-analog converter box to receive over-the-air broadcast television after the transition date. Retailers must inform consumers by displaying a sign that they are selling TV equipment with only an analog tuner with a referral for more information to the Federal Communications Commission at 1-888-225-5322 (TTY: 1-888-835-5322) or visit the Commission’s digital television website at: www.dtv.gov.

How do you determine whether your television equipment purchased prior to May 25, 2007 is a DTV? Your DTVs and digital television equipment will have labels or markings on them, or statements in the informational materials that came with them, to indicate that they contain digital tuners. These labels or markings may contain the words “Integrated Digital Tuner” or “Digital Tuner Built-In.” If your television equipment contains any of these labels or markings, you should be able to view digital over-the-air programming without the need for a digital-to-analog converter box. You do not need an HDTV to view free over-the-air digital programming. As long as your television equipment contains a digital tuner, you can view over-the-air digital. An HDTV is only necessary if you want to view digital programming in “high definition.”

To help summarize DTV for you, here are some quick facts:

Analog
~Date for final transition to digital is June 12, 2009. After that date, full-power stations will only broadcast digital signals.
~Consumers will always be able to connect an inexpensive receiver, a digital to analog converter box, to their existing analog TV to decode DTV broadcast signals.
~Digital to analog converter boxes will not convert your analog TV to high-definition.
~Analog TVs will continue to work with cable, satellite, VCRs, DVD players, camcorders, video games consoles and other devices for many years.

DTV
~Digital cable or digital satellite does not mean a program is in high-definition.
~Digital pictures will be free from the "ghosts" and "snow" that can affect analog transmissions.
~Multicasting is available.
~HDTV is available.
~Data streaming is available.

HDTV
~High-definition broadcasts offered.
~Best available picture resolution, clarity and color.
~Dolby theatre surround-sound.
~Dolby surround-sound.
~Wide screen "movie-like" format.


http://www.dtv.gov/whatisdtv.html

~ Lester Miyasaki, National Sales Manager


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WTI (Wireless Technology, Inc.)

Video Surveillance Products Dedicated to the Broadcast, Global Security and Transportation Markets!

www.gotowti.com ● www.wirelesstech.com

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