DIPOL Weekly Review - TV and SAT TV, CCTV, WLAN

What about WiMax? The leading WiMax investment - building all-American network - runs up against difficulties. In July 2007 Sprint Nextel and Clearwire signed Letter of Intent to partner on nationwide WiMax network. They planned to join forces to build the first all-American mobile broadband network using WiMAX technology, and make it available for about 100 million Americans by the end of 2008.
The budget for the first stage of the project amounted to 3 billion USD, the total expenses should not exceed 5 billion USD. Sprint Nextel was due to build out 65% of the network, Clearwire - the remaining 35%. Unfortunately, in November Clearwire withdrew from the project. It was one month after Gary Forsee, the CEO of Sprint Nextel and chief WiMax cheerleader, had stepped down. Sprint intends to pursue the venture, but the details will be announced next year.
Compared with that situation, the news from Russia and India are very optimistic. Comstar, the Russian telecommunication operator, has signed with Intel the agreement on launching WiMax network in Moscow by end of 2008. It will use IEEE 802.16e mobile standard and enable the subscribers to access Internet, VoIP , and TV - both in the case of fixed and mobile users.
Many experts think that the best prospects for WiMax are in the countries having underdeveloped telecommunications infrastructure. A good example is India. In this market, the leading world manufacturer of WiMax chipsets, Beceem, with its main R&D center located just in India, will supply Tata Communications company which, basing on WiMax, plans to revolutionize Indian telecommunications.

Mobile WiMax device of Samsung that is one of the world leaders

Which RF amplifier is best for one-family home - outdoor (mast) or indoor? In the respect of signal quality, it is better to use mast amplifier, e.g. AM-417 R903717, AM-316 R903052, or AWS-1021 B11551 - due to lower noise. The received channels are amplified before combining, and the possible interferences penetrating the shield of the coaxial cable are not amplified at all.
There is possibility of independent adjustment of the gain of each antenna path. This way the risk of overdriving the receivers is minimized. So, mast amplifiers are especially recommended for difficult reception conditions. However, because of outdoor operation, they are more affected by storms and hard weather conditions.
Indoor amplifiers, like HS-013 R82010, HS-013A R82020, CA-215 R90461, or AI-200 R90450 can be used in areas of good reception. They have to cooperate with antenna diplexers, e.g. ZA-4M C0340 or ZA-1 C0315. They are equipped with independent gain control in VHF and UHF bands. It is very important feature, due to different signal strengths in these bands (usually VHF transmitters are more powerful). It allows to avoid excessive signals that could cause intermodulation products.

Terrestrial signals are amplified by popular indoor device HS-013 R82010. Multiswitch installation in one-family house makes it easy to add satellite receivers.

Multiswitch installation in building with many staircases. As an example we may consider such installation in a 5-story apartment building with three staircases. Each of four apartments on a story has to be provided with satellite and terrestrial signals. The terrestrial signals are amplified by ZG channel amplifiers. Satellite signals from Quatro converters are distributed via satellite taps and splitters to individual staircases equipped with multiswitches. If needed, there should be used SA-901 R70901 amplifier.
It is only an example - every such an installation will require individual design.

Multiswitch installation in building with several staircases

Camera housings and brackets - certification requirements. Most cameras placed outdoors need housings with heaters and thermostats. Thermostat switches on the heater usually below 10 deg C. Temperature conditioning is very important to keep proper quality of the image. In the case of "bare" housings, except summer, there is a big risk of fogging up the pane and lenses, and condensation of steam even on metal and other parts of the housing and the enclosed camera. It is very risky for every electronic device. In turn, summer time may be dangerous for cameras placed in the heat of the sun - especially advanced models with powerful processors require housings with fans.
The housings equipped with heaters and fans, to acquire CE marking, have to comply with Low Voltage Directive (LVD) and Electromagnetic Compatibility (EC). All housings and brackets have to fulfill RoHS criteria (Restriction of the use of certain Hazardous Substances in electrical and electronic equipment).
Watertightness, or generally- Ingress Protection level - is described by IP specification, developed by European Committee for Electrotechnical Standardization - CENELEC.
In many countries, including EU, the equipment without the above listed certificates is not allowed to be used at all. The installer would incur a high risk especially in the case of gas/petrol stations, industrial plants, or city monitoring.

Multi-purpose pan/tilt IP camera. The rotating camera GPOWER-S2 M1220 finds various applications. The set includes remote controller which is very useful in the simplest camera - monitor installations. Using the K9152 system control unit, it is possible to control the camera in large systems. The highest functionality is achieved with IP module K2124 - the dedicated video server. It allows to integrate the camera with NUUO K3108 system. This way the camera provides full functionality of pan/tilt IP device.

GPOWER-S2 can be used both as handy analog device with pan/tilt control and a fully-functional rotating IP camera

Outdoor (IP66) Day/Night IP camera with IR illuminator - Pixord P428. P428 K1136 is the first outdoor IP camera for all seasons from PIXORD. The camera module has been placed in watertight IP66, aluminum housing equipped with 230VAC/12 VDC adapter, heater and fan. The latter elements ensure reliable operation even in extreme weather conditions - they switch on and off automatically to maintain proper internal temperature.
The components used - AI lens with adjustable length, Day/Night CCD from Sony (540 TVL), built-in IR filter - ensure high quality images. The camera can work in color or in B/W mode with IR illuminator (operation range up to 100m). The threshold can be adjusted.
The camera provides M-JPEG and MPEG-4 coded bitstreams that ensure even DVD quality of the recorded video. Real-time transmission allows for transfer up to 25 fps at 720x576 resolution (PAL).
Both configuration and monitoring are performed via Internet browser. The camera supports RTSP protocol, which enables the user to employ popular multimedia players like Quick Time Player or VLC.
The manufacturer adds free software package that allows live monitoring and recording of images from up to 32 channels. Pixord cameras can also be managed by commercial software from Milestone, NUUO, D3Data, Griffid and other leading producers.

PiXORD P428 K1136

Link-backup in IP CCTV system. Monitoring systems should be equipped with emergency power supply and should provide backup copies of recorded data - this is well known recommendation. But another problem may be caused by failure of transmitting link. The solution is provided by use of separate additional link. Such independent line may be sometimes indispensable to guarantee safe transmission of the most important data. Unfortunately, majority of IP cameras have only one Ethernet port. This is an disadvantage that makes it impossible to double the link and exposes the system to possible breakdown.
All IP cameras and videoservers from ACTi have been equipped with two RJ-45 ports: WAN and LAN, which, aside from basic functions, may be utilized for implementation of backup link. The transmission is then performed by WAN port, but in case of interruption, the data stream is redirected to LAN port. To run this function it is needed to activate Failover option in the camera settings.
Recapitulating, monitoring systems should employ not only UPS and data backup solutions, but also additional, separate links in case of failure, intentional damage etc.

IP cameras from ACTi.

Damage of the link in an unprotected system.

Damage of the link and automatic switchover to the backup link.

IP monitoring in LANs - network capacity. The traffic generated by IP cameras depends on the number of transmitted frames per second, resolution, as well as compression type and factor. For ACTi cameras, the maximum stream (for one camera) is 3 Mbps, i.e. 375 kBps. It means that 10 cameras need 4 MBps, and 20 - 8 MBps rates. At this level we reach the practical capacity of 100 BaseT Ethernet. Having two recording servers, each supporting 20 cameras (apparently, there are much bigger systems), it is indispensable to use as the backbone the Gigabit Ehernet, or limit the camera bitrates e.g. to 200 kBps (ca. 1.5 Mbps).

Gigabit Ethernet used in monitoring system

Power level of the received signal and SNR. The SNR or S/N (Signal-to-Noise Ratio) parameter is given in decibels (dB). It describes the ratio at the frequency in question.
The speed rate of wireless link depends on the power level of the received signal and its ratio to the noise. Even well-balanced radio link will be useless in case of high noise level. We have no influence on ambient electromagnetic noise level. The noise includes all unwanted radio signals that can deteriorate operation of wireless link or even make it idle. If the interference is in the working channel, even high power level of the received signal will not protect us against decrease of transfer rate.
Unexpected transmission interruptions and/or large number of lost packets can indicate decrease of SNR, e.g. some interference has occurred.
However, the most frequent reasons of SNR decrease are: water-soaked RF cable connecting the RF device with the antenna (e.g. due to damaged sheath), water-soaked connector(s), moved antenna (especially in the case of offset or parabolic antenna with narrow half-power beamwidth), mechanical damage of the antenna. The diagnostic testing of the installation has to be started with inspection of the physical condition of these elements. The quality of the components used is vital for reliability and longevity of every installation.

The problem with interferences is more difficult to tackle. It may be a "competing" service provider using the same or close channel. The countermeasures include:

• change to other, free channel
• change of polarization of the antennas
• use of client antennas with narrower beamwidth
• increase of RF power levels
• change to more powerful antennas

Illustration of S/N definition

We have written about:

PoE adapter with leads for LANs. The PoE set N9205 contains two passive devices shown in the picture...
- archive DWR of Sept. 17, 2007

Direct connection to telephone line and link sharing. Sharing of internet connection provided by xDSL technology (e.g. Neostrada in Poland) is a very popular way of connecting several computers to the Web at home...
- archive DWR of Aug. 27, 2007

Modern SMATV/MATV systems - some tips for designers. Exchange of the main installation equipment in a building requires considerable financial outlays. It is also a challenge for the residents. It is the reason why...
- archive DWR of Oct. 1, 2007

Index of published issues.