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Pre-Sale FAQ's

Should I choose Wireless or Wired Cameras for my security system?

There are many retailers offering wireless cameras these days, and boasting about the range, and quality as well as the ease of installation of these cameras...However, they neglect to inform you of the major flaws of a wireless camera system!

Wireless cameras are not secure! These cameras are easy to install, but they can allow a professional, or even an amateur who has a few dollars and access to a Radio Shack® store, to see inside your house or business, and case the robbery from the outside.

This defeats the purpose of a Security Surveillance System!!! Now you never know who is watching you on your own cameras!

These cameras operate on very crowded frequency bands which can be interfered with by a Mobile Phone, Wireless Access-Point, Wireless Network Card, or many other wireless devices. This also demonstrates how easy it is to disable the camera system from outside of your home or business.

Wireless cameras are not stable. The pictures flip, and the least disturbance in the area, such as a person walking by the receiver can disturb the picture.

Finally, the wireless cameras broadcast on the same frequency. You can only have one wireless camera in an area. There are multiple frequency cameras that come with multiple frequency receivers, but not only do the cost more, they are also not reliable, and suffer from channel drift as the video from one channels drifts into the next.

In our our experience a Wired Surveillance System is the only solution!.

CAUTION: You can only have one single frequency wireless camera in an area, as they broadcast on the same frequency. If you have two or more, all you will get is noise when you go to view them on your monitor.

There are cameras that are multiple frequency cameras, and they require multiple frequency receivers. The start in price at $120.00 US each. They are limited to 4 channels, Unfortunately, apart from being expensive, they also suffer from channel drift, as the signal from one channel drifts into the other channels. Not an ideal set-up at all.

There is one really good reason to purchase a wireless camera. That is for its ability to be set up quickly without stringing wires. So we suggest you consider, 3 wired cameras and one wireless camera to take advantage of this capability to move one camera around easily, without compromising the entire set-up.

Interesting Wireless Story


I owe you you guys an apology. I was raised that if you make a mistake, you admit to it and take your lumps.

I finally found enough time to work with the camera set, it’s a quiet Sunday.  If you remember, I was trying to set it up so we could monitor Main St. from the police station. I mounted the camera on a phone pole within visual sight of the station, about 80-90 feet away. Both DIP switches were set on 2. As I told you before, I got a VERY distorted video and audio. I put the receiver in my police car and used a power converter to run it and drove up and down Main St. The signal would get better and worse and seemed to have images that I had no idea what they were.

I finally got disgusted and unplugged the camera and….. Voila. I got a steady, clear picture. Of what, I had no idea. With some detective work, I was able to determine that I was seeing the front door of an antique shop on Main St., from the inside. Yes, I saw the camera inside.

Now, I ask you, what are the chances that there would be another wireless camera running, in the same area, on the same 2.4g frequency, WITH THE DIP SWITCHES SET THE SAME!!!!

I changed my switches to 4 and the camera set works perfectly.

Do you feel sorry for me a little? Again, I’m sorry for the confusion and tense moments.

- cop

What is the difference between wired and wireless cameras?

Wired cameras have a video cable that runs from the camera to the video input jack on your recording or viewing device. Wireless cameras have a built-in transmitter that sends the video signal to a receiver. The receiver connects to the video input jack on your recording or viewing device.

What is the range of the wireless cameras?

The standard wireless cameras have a range up to 700 feet, depending on the number and type of objects you are transmitting through. The commercial grade transmitter has a 15 mile line of sight range (1000-3000 foot indoor range). Line of sight means there is nothing between the transmitter and receiver, for example building top to building top.

Will cordless phones interfere with the wireless cameras?

Cordless phones that operate in the 900MHz frequency will not cause interference with our wireless cameras. Cordless phones that operate in the 2.4GHz frequency will cause interference with our wireless cameras.

Frames per Second

Most DVR capture cards are 30 frames per second cards. (NTSC - North American Video Standard) When they are being used to run PAL cameras (European Video Standard) the frames per second rate is 25.

If you attach one camera to the card then it will view and record at 30 frames per second. If you attach two cameras, that resource is shared between the two cameras, and you can view and record at 15 frames per second. If you attach four cameras, then you can view and record at 7.5 frames per second.

Why frames per second is not that important

Well, it is, if you are using the card to study the mating habits of hummingbirds!

But we believe that the object in good surveillance is to be able to obtain high quality images that you can email to the police, print out on your color inkjet, and that can be used to prosecute an offender.

When you are running four cameras on a 30 fps card, an illegal act that takes 1-2 seconds, will produce 7 - 15 pictures that you can use to prove your case to the police.

A 30 fps card is by far your most cost effective choice for professional surveillance. If you absolutely need higher frame rates, consider buying more than one card, and then you could have up to 4 cards in one machine, driving 4 cameras, each with 30 frames per second viewing and recording.

As soon as you go to the internet viewing, however, your frame rate will drop again, because the internet slows down the process.

Bottom line, 30 frames per second total resource is most likely all you need in 95% of the time you need surveillance.

Want to drive 8 cameras? - Purchase 2 cards - you need 2 PCI slots
Want to drive 12 cameras? - Purchase 3 cards - you need 3 PCI slots
Want to drive 16 cameras? - Purchase 4 cards- you need 4 PCI slots

What is a LUX in the camera rating?

To see properly, a CCTV camera requires a certain amount of light produced by natural or artificial illumination. B/W cameras work with any type of light sources, but color cameras need lights that contain all the colors in the visible spectrum for best color imaging.

The amount of light is defined by LUX (Lumens per Square Meter). One LUX is one candle light volume at one meter distance. Followings are some examples of natural lights expressed in LUX.

Natural LUX Examples
Full daylight: 10,000 LUX
Very dark day: 100 LUX
Twilight: 10 LUX
Deep twilight: 1 LUX
Full moon: 0.1 LUX
Quarter moon: 0.01LUX

View the LUX ratings of your camera to determine the LUX necessary for your application.

What makes one camera better than another?

Weatherproof vs. Indoors

Weatherproof Camera

We realize that most of you want a camera to observe the outdoor areas of your home. In some cases, there are compelling reasons to have a camera covering your driveway, backyard, or the front of your home. We offer cameras that can withstand the effects of rain, snow, wind and wide ranges of temperature changes.

Camera Housing

In most cases when you see a weatherproof rating it means the camera can withstand most types of moisture, it does not mean the camera can tolerate being submersed in water. Weatherproof cameras have special gaskets to keep the effects of the environment from damaging the camera's pickup element and electronics. When indoor-only cameras are used outdoors, the camera will likely fail in two to five years (even if it is mounted under an eve or soffit.) If you find a camera that you like and it is not rated for outdoor usage, we have an Aluminum Outdoor Housing that the camera can be installed into and be protected from the weather.

Light Sensitivity

I mention earlier that all cameras come with a rating to indicate how sensitive the camera is to light. This figure is called the LUX rating. One lux of light is the amount of light from a candle measured from one meter away. The lower the lux rating on a camera, the less light it needs to 'see' properly. Most folks will not be lighting the outside of their homes like a television studio, so the lux rating on a camera is very important. In general, black & white cameras will have a lower lux rating than will color models. If the camera is being used outdoors, like to monitor a backyard pool, a color model will look great during the day, but come nightfall, it will be totally back and the picture will be unusable. An equivalent black and white model will provide a decent picture will only a porch light turned on. Since the lighting outdoors can vary, we suggests using a black & white camera.

Some of the black and white models have the ability to operate in total darkness. Black and white cameras have the ability to pickup light that humans can't see. Some cameras like theses have infrared illuminators built into the camera:

The illuminators will shine out infrared light a few feet (typically 12 feet) so that in total darkness the area being covered by the camera will appear fully lighted. The Ir light will not be perceptible to humans and is not harmful in anyway. This is the same technology used on the dark rides at theme parks all over the world. We also offer the Indoor/Outdoor IR Illuminator that will come on automatically when dark and flood an area up to 40 feet long and 56 degrees wide with invisible Ir light. Color models are not sensitive to Ir light, so it's best to choose a black and white model with the Ir Illuminator.

Imager Element

When comparing cameras, you may notice price differences for what appears to be basically the same thing. What they rarely mention about these toy cameras are the specifications. When looking at any camera, check for the specification that lists the imager used. The imager is the device that converts the light into electrical signals. Much like a microphone converts sounds into electrical signals, cameras use an imager. Most budget models use inferior CMOS imagers. The majority of our cameras use the superior CCD imager.

Even within CCD imagers, that can be quality differences. The larger the imager, the better the picture will be. Below are there screen captures from cameras with 1/4", 1/3" and 1/2" CCD imagers.

1/2"CCD 1/3" CCD 1/4" CCD
High Sensitivity Color
Video Camera
Color Adjustable
In-Wall Camera
Color Sun Visor
Video Camera

Cameras that have digital signal processing will deliver a better picture than similar models that lack this DSP feature.


This is often an overlooked specification. All the cameras will need a lens to focus the light onto the CCD imager. Most of our cameras come with a fixed lens. Only our C-mount cameras, which are designed for commercial installations, require the purchase of a separate lens. On most of our web pages for cameras, we not only give you the field of view in the specification table, but an actual image captured from the camera is on most pages!

A camera with a wide-angle lens will pick up a larger area than a narrow model. That is to say, a 6mm camera lens will pick up less area than a 3mm lens. The area in the center of the screen will have more detail with the 6mm model, but at the sacrifice of picking up less area overall. If you need to read a license plate from a vehicle with your camera, a camera with a narrower lens (higher mm) will be a better choice. However, if you want to cover the broadest area, like your front yard and don't care about the details of a visitor or intruders face, a camera with a wide angle lens (lower mm) will be an ideal choice. The trade off is that you will be giving up some detail to get a broader picture.

For our C-mount cameras, we have two variable zoom lenses that can be attached. These lenses are ideal for locations when you not sure how much of an area you will need to cover. Below are two examples of different lens angles.

3.5mm view 8mm view
Color Camera with
a 7683D Lens
Color Camera with
a 7683D Lens

Some of our cameras are built into inconspicuous devices like clocks, picture frames, and non-functional smoke detectors. The camera board in these units use a special kind of lens called a pinhole lens. The camera looks out a small hole no larger than an eight of an inch. There will be a small decrease in quality between a pinhole lens camera and a camera with a conventional lens.

Regular Lens Pinhole Lens
B&W Adjustable
In-Wall Camera
Working PIR

No discussion about cameras can be complete without addressing the issue of focus. When we talk to callers in our Tech Support department about cameras, the question of what will be in focus frequently comes up. All the cameras with a fixed lens will have a large depth of field. This basically means that everything from 12 inches to infinity will be in focus. Point the camera at the moon, and it will be in focus. If the camera is pointed at your nose from arms-length, it too will be in focus.

Where's the Audio?

If you look through our Cameras, you will notice that most cameras don't have a built-in microphone. The trend in the industry has been to eliminate the microphone in cameras.

Over the last few years, United States federal laws have been amended or interpreted by the courts to put limitations on audio 'eavesdropping' devices. It seems that while you can justifiably point a camera at your front door and see who is at the door, the camera's microphone may pickup surrounding sounds. Those people producing the sounds may not be aware that they are being monitored or recorded. One of our suppliers reported that they were 'visited' by representatives of the U.S. Department of Justice over this issue. After this event, they immediately discontinued all cameras with audio. We do have a few models with audio still for sale.

Video surveillance cameras can be an effective way to monitor and record the activities on your property. Whenever using these devices, be sure to use good judgment on its placement. Never use a camera in a place where there is an expectation of privacy. If you have questions on our cameras, email our Tech Support staff with your questions or browse the camera pages on our website:

Let's Talk About Resolution

The resolution of CCTV system is usually measured by TV lines in the field. The vertical TV lines has maximum 350 TV lines in 525-line NTSC system and is not variable. But the horizontal TV lines, which is used as the parameter of picture quality, vary depending on the quality of camera, lens, transmission and monitor.

Camera Resolution

The industry of CCD video camera sensor uses pixels (picture elements) as its quality parameter. Medium resolution of B/W camera in EIA system is 510 horizontal pixels by 492 vertical pixels and is equivalent to 380 TV lines. High resolution is 768(H) x 492(V) pixels and equivalent to 570 TV lines. Color camera's medium resolution means 330TV lines and high resolution needs more than 460 TV lines.

Monitor Resolution

The monitors in NTSC system have 525 vertical scanning lines regardless of their size. The horizontal 700 TV lines of B/W monitors represents medium level and more than 900 TV lines means high resolution in EIA system. The color monitor's horizontal resolution of 300 TV lines means medium quality and that of more than 450 TV lines means high resolution.

To maximize the system's resolution, it is recommended to choose a monitor which has better resolution than that of the camera.

What are the minimum computer specifications for running a DVR system on my PC?

Each card we sell has its own minimum system requirements

What is a Dedicated PC?

A Dedicated PC, is a PC that is not used for any other purpose. A DVR PC constantly needs access to all of the PC's resources. Because of this, operation of any other programs, surfing the internet, or any other activity aside from running the DVR program, can cause poor performance, failure to record video properly, or system failure.

What is the difference between a CMOS and a CCD Camera?

To put it simply, the difference is in the quality of the image sensor.

A CMOS camera has a less-expensive image sensor. The other benefits of CMOS are size, and low-power consumption. Most CMOS cameras can even be operated for several hours on a single 9-volt battery! The low-power consumption comes at a price however. CMOS cameras have a lower resolution and less color quality than the CCD cameras.

However, the CCD Cameras are much more sensitive to power fluctuations, due to the fact that the CCD Sensors have 4 integrated processors compared to the one processor found on a CMOS sensor. CCD cameras usually have much better picture quality, resolution and color balance. The drawback of a CCD camera is high-power consumption and sensitivity to minute voltage changes It is highly recommended to use a AVS battery backup unit for the CCD Camera Power adapters and DVR PC.

How should I place my cameras in order to ensure I catch video that will capture the most relevant shots?

While this is a very broad question, here are some tips at placing your cameras.

Camera Placement Tips:

Never angle a camera to look straight down.

A camera that is pointed straight down, will only catch the top of a perpetrators head. The camera will most likely miss many of the distinguishing characteristics that can be used to identify a person later if necessary.

Always make sure to have a camera facing all entrances

It is a fact, that the best time to catch the facial features of an individual is during their entrance into the building, whether it is your home or your business. Other cameras can catch the act of someone stealing, however, without the critical entry-shot you may not be able to identify the individual

Never allow direct sunlight to touch the lens of the camera

Regardless of which cameras you use, make sure that the cameras are never mounted in such a way, that sunlight will directly shine into the lens. This will cause the Image sensor to discolor and fail. Direct sunlight will also immediately void any warranty.

I/R Cameras within 20 ft. of subject being viewed

I/R Bulbs emit an invisible light spectrum that will illuminate a subject even in complete darkness...however, the light will only project out 20-40 ft. to illuminate the target

Always plug cameras into a surge suppressor or Battery Back-up unit

Cameras are extremely sensitive to voltage changes and can fail prematurely. Voltage changes will also void the cameras warranty. Plug the power adaptors into a power bar with surge protection.

Select a lens that will provide no wider of a field of view than is needed.

The wider the field of view, the smaller objects in the camera will appear. Visit our eBay Store lens selection page to help you select the appropriate lens for your application.

How do I select a Camera?

Selection of the best camera to suit your needs should be based on where the camera is to be located, and the light conditions of the location.

Dome Style Camera

Usually used in an indoor business or home environment. Usually the Dome camera's curved shell helps to disguise what direction the camera is facing.

You might see these cameras commonly in Apartment buildings, Retail Stores, Hallways, Convenience Stores, Gas Stations, and many other applications

A Dome camera can be mounted easily on the ceiling or the wall, and generally will rotate 360° during installation. The cables for the camera are generally fed through a small hole in the wall or ceiling, so no wires are visible after installation.

Bullet-style Weatherproof Cameras

Usually used in an indoor or outdoor business or home environment. The weatherproof housing of this camera is excellent for most outdoor installations to -30 degrees. For use in harsher climates, a CS Mount camera with outdoor housing should be used.

You might see these cameras commonly in Apartment buildings, Retail Stores, Hallways, Convenience Stores, Gas Stations, and many other applications

Presently, the majority of these bullet style cameras have IR illumination, for use in pitch black night-time environments!

C or CS - Mount Cameras

These cameras can be used in an indoor or outdoor environment (when outdoor enclosure is used).

These are the most common cameras for a professional installation, banks, jewelry stores or an installation where lens changes may be necessary.

C and CS - Mount cameras are often sold without lens, as each application will require a slightly different lens in order to capture the desired picture.

What if I don't see the camera I want?

DuncansOnline is constantly expanding our line of products. We are listing them as fast as we can on Amazon. Please check back to our Amazon store often to discover our new products and review our older ones.

Do the covert cameras have audio?

Audio is only available to law enforcement agencies due to federal law Title 18, Section 2512.

What is the difference between a Digital Video Recorder (DVR) vs. an Analog VCR based video surveillance system?

The Digital Video Recorder (DVR) system records high resolution digital images to a hard disk drive (HDD) and eliminates the requirement of maintaining VHS tapes. Since the video images are stored digitally, the image quality will not degrade overtime, as would a VHS tape when recorded over multiple times. The time saving intelligent search capabilities of a DVR will enable the user to locate the desired video clips via user defined parameters (camera, time, date, etc.) vs. Fast Forward and Rewind functions of a VCR.

What is a DVR Card?

DVR Cards enable the user to convert their computer into a Digital Video Recorder. The DVR Card(s) is typically installed in an available PCI slot of a computer. DVR cards are bundled with video surveillance software which allows the user to record and display multiple cameras simultaneously from the camera site or a remote location.

How long will a DVR record for?

Frames per Second 80 GB 120 GB 240 GB 360 GB 480 GB 960 GB
30 fps 320 hrs 480 hrs 960 hrs 1440 hrs 1920 hrs 3840 hrs
120 fps 80 hrs 120 hrs 240 hrs 360 hrs 480 hrs 960 hrs
240 fps 40 hrs 60 hrs 120 hrs 180 hrs 240 hrs 480 hrs
480 fps 20 hrs 30 hrs 60 hrs 90 hrs 120 hrs 240 hrs
Estimated hours of recorded video at 320 x 240 resolution utilizing the WAVELET Compression option.

Can a DVR record upon detecting motion or via a schedule?

Yes. Each camera can be configured independently to record upon video motion detection or via a schedule.

How do I access my video from a remote location?

The user may access the video from a remote location via a standard modem connection or a high speed internet/intranet connection.

What is the viewable area for your cameras?

The viewable area is determined by the camera’s lens size (see lens chart below). Our covert cameras incorporate a 3.6mm lens.

Lens Size Field of View Recognizable Distance Best Picture Distance Viewable Area @ Given Distance
3.6mm 92 degree F.O.V. 10 – 15 feet 5 feet 14’ (W) x 10’ (H) @ 10 feet
6.0mm 57 degree F.O.V. 20 - 25 feet 7 feet 16’ (W) x 12’ (H) @ 20 feet
8.0mm 38 degree F.O.V. 25 - 30 feet 10 feet 18’ (W) x 14’ (H) @ 30 feet
12mm 26 degree F.O.V. 35 – 40 feet 12 feet 16’ (W) x 12’ (H) @ 40 feet
16mm 15 degree F.O.V. 50 – 60 feet 18 feet 15’ (W) x 12’ (H) @ 50 feet
Based on a 1/3” CCD Camera F.O.V - Field of View
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