Tips to Reduce Wireless Interference
Video baby monitors use different frequencies to send their signals. Often, these same frequencies are used by many other common household electronics, and as a result undesirable interference can occur. By purchasing a monitoring system that is most compatible with the other wireless electronics (if any) in your household you can get the best performance from your monitoring system.
In the past several years we’ve received many questions from our customers regarding which wireless monitoring units would best serve their purpose and how to modify their home environment to reduce interference. The objective of this article is to address these questions and help clarify the most common issues concerning the different frequencies and transmission strength of various types of wireless video systems.
Video surveillance monitors use different frequencies to send their signals. Often, these same frequencies are used by many other common household electronics, and as a result undesirable interference can occur. By purchasing a surveillance system that is most compatible with the other wireless electronics (if any) in your household, you can get the best performance from your monitoring system.
Most Prevalent Frequencies of Wireless Devices
5.8 GHz Overview
2.4 GHz Wireless Computer Networks (Wi-Fi)
The majority of new cordless phones now use the 5.8 GHz frequency bandwidth. Since, at this point, it’s rare to find video monitoring systems using this frequency, home/business environments with 5.8 GHz wireless phones in use will not create unwanted interference with present day video baby monitors.
2.4 GHz Overview
2.4 GHz is one of the most common frequencies for video baby monitors today. Not too long ago, most cordless phones and other devices used the 900 MHz bandwidth. As a result, when the 2.4 GHz band became available several years ago, manufacturers of wireless monitoring units flocked to it. Since the 2.4 GHz frequency range was relatively unused, it offered a high level of interference-free operation for the wireless devices that used it.
As a result, the 2.4 GHz bandwidth became the frequency of choice for the majority of wireless systems. This has caused the 2.4 GHz band to become over crowded and prone to interference issues, as there may be several wireless devices using this frequency in the home.
To address this, a new protocol called Frequency Hopping Spread Spectrum (FHSS) was developed. This is a digital wireless protocol that uses a channel hopping sequence based on an algorithm generated by the receiver. As a result, those digital wireless cameras which use the FHSS protocol, are is now highly secure and resistant to jamming and interference.
Probably one of the biggest cause of interference problems with 2.4 GHz wireless video baby monitors is the wireless network router. Wireless computer networks share this same set of frequencies and can be powerful enough to cause severe interference and limit the usable range of your baby monitor.
Whenever a computer in your house is on and connected to a wireless network, data is constantly being transferred over the network. This is true whether the computer is being used or not. When both the computer and wireless network are off, no interference will occur.
The rule of thumb then, is to use a 900 MHz wireless baby monitor, or any other frequency other than 2.4 GHz. From our own tests, 2.4 GHz baby monitors do not shut down nor severely disrupt the computer network (unless the two systems are very close together). On the contrary, the baby monitor will become un-useable due to the static from the interfering Wi-Fi computer network. As a result, we recommend against purchasing a 2.4 GHz baby monitor system when you have a wireless network router in the home.
900 MHz Overview
A few years ago, the 900 MHz bandwidth was the most popular frequency for many wireless devices. Devices such as cordless phones, wireless headphones, and wireless speaker systems that use this bandwidth will cause interference with a 900 MHz baby monitor.
While there are now fewer cordless phones today that use 900 MHz, they are still out there. So if you have a 900 MHz wireless device in use around your house do not purchase a 900 MHz baby monitor.
The majority of video baby monitors come with multiple channels. These extra channels can be used for multiple cameras. But they are also designed to provide the ability to select the channel with the least amount of interference. Be sure to try all channels to identify the one that provides the best performance.
Other wireless devices such as cordless phones, and even wireless computer network routers all have channel selectors. Moving some of these devices to other channels can also minimize interference.
In reality, however, since two devices on the same frequency won’t operate without interference, regardless of the channel settings on either unit, since the frequency separation between the channels is very small. Therefore, though adjusting the channels may provide clearer reception, don’t count on it to fix an interference issue. The best solution is to use devices that do not share the same frequency.
If neighbors are close by, such as in an apartment or condo, keep in mind that if they use some of the aforementioned wireless devices, they too can affect the clarity of the video of monitoring systems. After all, keep in mind that wireless computer signals and wireless audio/video signals are designed to penetrate walls and ceilings.
It can be rather daunting dealing with wireless interference issues coming from one or more of neighbors. It can also be a challenge determining the exact location of the interfering device. As mentioned above, the best answer is the "work around", and simply try to use a different frequency than the competing wireless device(s) next door.
The reception range of your video baby monitor system depends on several factors. The factors with the most impact on useable range are Transmission Strength, Geography, and Power, all of which are outlined below:
The transmission power of a wireless camera is the primary factor in determining the expected range of any system. Less expensive units will often save money by utilizing a less powerful and less expensive transmission system.
If the distance between where you plan to have the camera and receiver is short, then a less powerful unit will most likely work fine and save you some money as well. On the other hand, if the distance between the monitor and camera is great, then you will want to get a system capable of longer transmission ranges. For example, if the camera is to be upstairs and the receiver downstairs, or if your house has especially thick walls you will want to go with a more powerful unit. Another case is if your area has high levels of interference, you will want the additional power to "punch through" that interference.
There are two defined distance ranges specified for video baby monitors; they are "clear line of sight" and "obstructed".
Clear Line Of Sight refers to a flat open area, where there are no obstructions (such as a football field). Usable distance will be much greater when the camera and receiver can visibly see each other and there are no obstructions.
Unfortunately in the real world, most people use video baby monitors in the home, where the environment is rarely designed as a football field. Fortunately, all the frequencies used by video baby monitors are specifically designed to penetrate walls, ceiling, floors, and other obstacles that are commonly found between the receiver and camera. While these signals can pass through solid objects, it does come at the price of reduced range. The more barriers a signal must penetrate, and the denser those barriers are, the shorter the usable distance becomes between receiver and camera.
Obstructed distance is a rough estimate of the range you can expect when the space between the camera and receiver is obstructed by walls, ceilings, floors or other obstacles. This range will vary depending upon the number and density of obstacles the signal must penetrate in the particular environment.
Lastly, a camera is unable to transmit at its maximum capacity on a dead or dying set of batteries. Always make sure the camera is plugged in, or using a good set of batteries to ensure the most reception range out of your system.
If there is a gradual decrease in the reception range of your system and its running on batteries, chances are good that the batteries need to be replaced. Plugging the units into AC power is always best when the portability and convenience of battery power is not required. The majority of video baby monitoring systems allow both the camera and monitor to be powered by AC adapter or batteries.
In general, the monitor screens consume the most power, by far. When running on battery power most monitors have an auto-off function that turns off the monitor after several minutes of inactivity. This serves to preserve the battery life. When plugged in, the auto-off feature is usually disabled.
Cameras, in general, will use less power than receivers with a built-in monitor. However, ‘Night Vision’ cameras (those with infrared illuminators) use much more power in night vision mode than they do in daylight. The LED (light emitting diodes) lights work the same as mini-flashlights, which are invisible to the naked eye due to the infrared light spectrum. Since the camera consumes much more power when in night vision mode, a set of batteries will typically be drained before morning. So it’s best to plug in the camera and use the AC power if it’s to be used for extended periods of time in the night vision mode.
Rechargeable batteries have the advantage of not having to continually purchase expensive alkaline batteries and can be a big cost saving.
Night vision solves a very important issue with video baby monitors. Like the rest of us, babies usually sleep with the lights off. And the main purpose of a baby monitor is to monitor your infant while he/she sleeps. But cameras need light to be able to see. The solution is infrared (IR) night vision.
Humans are able to see the visible light spectrum. The wavelength just below the visible light spectrum is infrared, which we cannot see. Cameras however, can be designed to see infrared light, which is then used to illuminate the area. The majority of these night vision cameras can also operate in normal mode with regular visible light and full color. There is usually a selector on the camera that switches the unit between normal and night vision modes.
In order to illuminate the dark, small, yet powerful, LED (light emitting diodes) lights are built into the cameras and shine the infrared light. Most cameras have several IR LEDs, numbering anywhere from 6 to 18. These IR LEDs work just like an invisible flashlight, providing the light required by the camera to see in the dark room. The result is the dark room is now lit so the camera can see, but since the light is invisible, it will not disturb your sleeping baby.
The average range these IR LEDs are able to illuminate is up to about 8 feet. So they will not illuminate the whole room, but will be able to provide enough IR light to the immediate area in front of the camera to allow for viewing.
In normal operation mode most video baby monitors will provide a color video image. But when the system is switched into night vision mode the video image will go into black and white and the IR illuminators will be turned on.
Black and white provides better contrast and overall performance in low light situations. Color is not really visible until there is a substantial amount of visible light present.
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