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DIPOL Weekly Review - TV and SAT TV, CCTV, WLAN
No. 34/2007 (Oct. 8, 2007)
"Engagingly about Antennas - VI Summer 2007 Dipol Competition" - adjudicated. "Two things awe me most, the starry sky above me and the moral law within me".Today, especially in big cities, we can see less stars, the same with moral law, comparing it with the 18th century when Immanuel Kant lived, but... unquestionably more antennas.Usually, when we want to see them, we have to look high in the sky, like Kant, but what we see is rarely so exciting or inspiring to be worth philosophical reflection.Antennas and dishes cover facades and roofs, TV towers destroy landscapes. Being the background of our civilization, halfway between the ground and the sky, they may separate people, limiting direct contacts.
  • Such an air of sadness pervades the pictures taken by Barbara Sieja "Architecture of Cairo" (honorable mention), Bartlomiej Soltysiak "157" (honorable mention), "... in solitude" Piotr Rodzajewski (honorable mention). The common denominator of the pictures may be subtitled "In anticipation of the good news". Within this current it is worth to notice the works of Agnieszka Mlynarczyk, Magdalena Grenda, Sebastian Brzezinski, and Franciszek Kowalski.
  • Kant's philosophical yearnings have been explicitly expressed in the pictures "The eternal hope" of Ewa and Lukasz Karczynski. Marks of Plato can be seen in "Tapping in the wall" from Marcin Kaminski.
  • As usual, we have many pictures from travelers - exotic scenery astonishes us in "Boundless world" by Arkadiusz Jaworski.
  • In the works of Tomasz Kozlowski we feel the climate of old quarter of Krakow (Podgorze). This group, say "Let's preserve it for posterity", also contains interesting photos of Marcel Kasprzak and Tomasz Rys. But in this edition no-one was able to beat the beauty of roofs in the picture "Something new... discreetly" from Tomasz Mlynarczyk (honorable mention).
  • Birds adapt to "antenna forests". "Who will force us to pay license fees ? :-))" of Marek Koteluk is a witty summary of the forced coexistence. The picture "Break" of Jolanta Maj (II place) is a beautiful portrait with the antenna in the background.
  • In the work of Piotr Rzok "Unlimited imagination" we see an interesting composition combined with creative imagination and a piece of wit - three in one! (Dipol Technical Department award).
  • To highlight the beauty of antennas - impossible? After all, it is possible - see the picture of Anna Szczeblowska "Bird's Radio" (honorable mention), and, first of all, that of Agnieszka Sienkiewicz - "Meltdown" (I place).
Thank you for participation, and we still encourage you to notice interesting objects in the background of the sky, not necessarily the UFOs, inviting everyone to the next edition of the contest in 2008.
I place - "Meltdown" by Agnieszka Sienkiewicz
SMATV systems in apartment buildings - the cabling. Cabling in apartment buildings should enable the residents to receive any available channels. The best solution is 9-cable bus. It is recommended to use for this purpose highest quality coaxial cables, like TRISET-113 E1015_100, characterized by the best on the market screening efficiency, low loss, and very good matching. In the case of larger installations (above 100 outlets) and longer distances, the backbone cabling should be made with the cable TRISET-11 E1027_100.
The project may be completed with installation of multiswitches and connecting the subscriber outlets at the stage of construction, or designed to be finished by the future residents, according to their individual needs.
The scheme below shows 9-cable backbone, with signal branches. There may be used subscriber multiswitches MS-554 R70554 (for 1 converter) and MS-952 R70952 (for 2 converters). The installation allows to distribute terrestrial broadcasts as well.
SAT/TV TAP: Terra SS-5109-input Multiswitch: TERRA MS-952Multiswitch: Terra MS-554 (5-in, 4-out)
9-cable installation with signal branches, recommended for apartment buildings
Subscriber outlets. Depending on the application in specific RF distribution system, the outlets can be divided into several groups:
  • pass-through outlet - having high loss in the subscriber's branch, to be used in riser conduit as transitional device GAP-xx. This kind of outlets is also used in simple satellite installations (Signal R694110), where only one sat receiver is to be employed,
  • terminal outlet - having high loss in the subscriber's branch, to be used in riser conduit as the end device: R62370, equipped with the terminating resistor R66150. The equivalent in satellite installations is the outlet Signal R694100,
  • non pass-through outlet - characterized by low loss, to be used at the end of typical subscriber lines - R62110.
Pass through systems are rather historical now, due to problems with maintaining similar level in all outlets, risk of breaking the cable and interference of the user, large number of connections, and more difficult designing.
Another classification of outlets is based on the way in which they separate the TV and FM signals:
  • broadband - the separation (or rather division) is made with a splitter or tap,
  • band - the separation is made with a band filter.
There are also - very popular among customers - multimedia outlets, combining FM, TV, SAT functions with telephone and LAN applications. The example is Signal R694043.
Some tips for making antenna installations:
  • Due to growing number of PVR receivers there are recommended outlets with two SAT outputs(they need two independent satellite signals - for live viewing and recording).
  • There should be preferred band separation - it is better and ensures higher signal levels.
  • The last outlet in the series in a pass-trough system has to be closed with terminating resistor, unless it is dedicated end device. It is not allowed to connect outlets directly to splitters.
Monitoring of several locations with remote surveillance center. The main problem that has to be solved in this case is transmission and recording of video data. The solutions used in modern installations divide the video surveillance system into smaller units with individual servers. Management functions can be executed by client station connecting with the servers. Additionally, setting access rights, Internet browser will allow to follow the video online, e.g. when motion detection has been triggered.
Such solution can be can be implemented with ACTi devices, e.g. K1118 or K1312, very well prepared for monitoring of buildings, and dedicated software application NVR K3032 - network recorder equipped with all functions indispensable in professional system.
MPEG-4 IP Camera: ACTi ACM-1431MPEG-4 IP Dome Camera: ACTi ACM-3211
Video monitoring of two buildings with remote surveillance center
MPEG compression - part 1. Most of currently available IP cameras uses MPEG-4 compression. But it is based on the earliest version - MPEG-2, from which it takes many basic algorithms, - so we start from the predecessor. MPEG-2 uses GOP (Group of Pictures) and ME (Motion Estimation) method, reducing the number of packets streamed to the receiver. To cut down the size of transmitted files, the MPEG-2 encoder links the individual frames into the GOPs. During compression process the encoder creates Intra Frames providing full information about the image, and Predicted and Bidirectional Frames containing information on similarities in consecutive images that are in fact the vast majority of GOP. It results in limiting the amount of output data, as it is enough to send the differences between consecutive frames, instead of the full video stream. Aside from GOP there is used mentioned ME method, employing division of the image into macro-blocks (16 x 16 pixels). ME algorithm finds movement of the blocks and provides the results as shift vectors and differential images (P and B frames).MPEG-2 has been employed in DVD and DVB technologies, as well as it was used in a number of DVRs, partially replacing MJPEG and ensuring higher compression levels in typical CCTV applications. The main features of this standard include:
  • reduction of the image details that have minimum influence on the quality,
  • low sensitivity to errors,
  • compensation of motion - the transmitted information conveys mainly differences between consecutive frames,
  • typical bitrate: 6500 kbps (720 x 576),
  • maximum bitrate up to 15 Mbps.
Monitoring of entries. At the moment of opening the door a large amount of light comes into the room and the camera has to quickly adapt to the changeable lighting conditions. There is similar situation in the case of glazed door - the cheaper cameras do not provide satisfactory results. To avoid such intense light the installers usually mount the cameras as high as possible or on the side of the room. But such location of the camera does not allow good identification of the people coming in.
Professional solution is provided by application of cameras equipped with Super Wide Dynamic sensors (WDR), e.g. SN-587C/A/10 SWD M11205.
Follow-up dynamics of the cameras helps to avoid the situations where the main object is too dark, and the background too bright. The WDR function is possible due to high speed CCD sensor capable of two-sweep image processing. Then the two images containing details from the opposing areas (in terms of lighting) are superimposed on each other providing satisfactory image of the scene, with recognizable both the dark and bright objects.
Standard CCTV camera
CCTV camera with BLC function
CCTV camera with WDR sensor
Antennas for GSM, DCS, UMTS. The antennas designed for UMTS range (1.9 - 2.1 GHz) are the perfect solution to the problem of low signal in a laptop or mobile phone. The antennas that may be used in large cities with UMTS infrastructure, operating at 2 GHz, are available in two versions:
  • A7035 - UMTS outdoor antenna ATK-16/2 GHz (11dBi, with 10m cable &SMA plug),
  • A7044 - UMTS outdoor antenna ATK-P1/2GHz (7dBi, with 5m cable &FME socket),
whereas in the locations where there are available only 900 MHz or 1700-1800 MHz services, logarithmic antennas are used, e.g.:
  • A7040 - GSM/DCS/UMTS/HSDPA ATK-LOG antenna with FME socket,
  • A7041 - GSM/DCS/UMTS/HSDPA ATK-LOG antenna with 5m cable &SMA plug.
The factors influencing maximum range of wireless network. The range depends, among others, on:
  • the features of the devices used:
    • Tx output power
    • attenuation of feeding cable
    • antenna gain
    • Rx sensitivity
  • the environment:
    • attenuation of the space between antennas (can be estimated with the FSL model)
    • interferences caused by other devices (they cannot be predicted a priori - it is needed a certain margin of power compensating possible interferences)
    • high attenuation of some obstacles (walls, ceilings, trees etc.).
To minimize attenuation of the feeding cable it is advised to use cables up to 6 GHz. They are characterized by considerably lower loss in 2.4 GHz band. We may recommend the family of Tri-Lan.Main features of the Tri-Lan cables:
  • low loss (as far as 20% lower than of H155)
  • perfect matching
  • high screening efficiency (90dB at 2.4GHz)
Coaxial Cable 50 ohm: Tri-Lan 240 [1m]
The details of Tri-Lan 240 cable
Coaxial Cable (50 ohm): Tri-Lan 400 WLL [1m]
The details of Tri-Lan 400 cable
Use of Tri-Lan cables in 2.4 GHz systems will allow migration to 5 GHz band without replacing the cabling.
Products nominated to the Product of the Year prize. The organizers of SatKrak (Krakow, 18-20 Oct 2007) have recommended for the prize two groups of products distributed by Dipol - Triset cable family and Signal line of RF accessories. More on the nominated articles on the "Dipol virtual stand".
DIPOL at SatKrak 2007: October 18-20, 2007, Krakow, POLAND
 
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