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Press space to start!. Presents… Page 0100 0100 Text-TV Your favourite Channel Monday 18. October 1999 Connecting and Return Path in CATV Networks.

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Presentation on theme: "Press space to start!. Presents… Page 0100 0100 Text-TV Your favourite Channel Monday 18. October 1999 Connecting and Return Path in CATV Networks."— Presentation transcript:

1 Press space to start!

2 Presents…

3 Page 0100 0100 Text-TV Your favourite Channel Monday 18. October 1999 Connecting and Return Path in CATV Networks

4 Page 0100 0100 Text-TV Your favourite Channel Monday 18. October 1999 You have probably seen this before...

5 Page 0100 0100 Text-TV Your favourite Channel Monday 18. October 1999 Your favourite TV Channel News.............. 110 Sport............. 200 Latest............ 130 Advertising..... 700 TV today........ 320 Cabelcon …..... 600

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7 #ge 0800 0p00 Te((?-V Yo¤¤ fav§§it Cha||| { "@context": "http://schema.org", "@type": "ImageObject", "contentUrl": "http://images.slideplayer.com/7/1640359/slides/slide_7.jpg", "name": "#ge 0800 0p00 Te((?-V Yo¤¤ fav§§it Cha|||

8 Page 0100 0100 Text-TV Your favourite Channel Monday 18. October 1999 Your favourite TV Channel News.............. 110 Sport............. 200 Latest............ 130 Advertising.... 700 TV today........ 320 Cabelcon …..... 600 Right? - and you know why too!

9 Page 0605 0605 Text-TV Cabelcon Connectors Monday 18. October 1999 Lacking system performance…!

10 Page 0607 0607 Text-TV Cabelcon Connectors Monday 18. October 1999 Safe signs of poor system performance with analogue TV signals: Ghost pictures

11 Page 0610 0610 Text-TV Cabelcon Connectors Monday 18. October 1999 Like this...

12 Page 0612 0612 Text-TV Cabelcon Connectors Monday 18. October 1999 Safe signs of poor system performance with digital downstream signals... Increased bit error rate. Typical visible results of this will be...

13 Page 0615 0615 Text-TV Cabelcon Connectors Monday 18. October 1999 TV-Text unreadable. Noisy (or no) digital sound (NICAM).

14 Page 0618 0618 Text-TV Cabelcon Connectors Monday 18. October 1999 - and at digital upstream signals? (using the return path band)

15 Page 0620 0620 Text-TV Cabelcon Connectors Monday 18. October 1999 Poor system performance in a CATV network could originate from… Poor return loss values Poor carrier to noise level Insufficient screening followed by... Ingress of noise and unwanted signals

16 Page 0623 0623 Text-TV Cabelcon Connectors Monday 18. October 1999 There can be many reasons for decreased performance. Here we will concentrate on... Poor or incorrect cable preparation and connector installation. Unreliable connector quality.

17 Page 0626 0626 Text-TV Cabelcon Connectors Monday 18. October 1999 Most return path problems originate at the subscribers end of the network... Its a well-known fact, that 75-80 percent of service calls are related to drop installation. -and that around half of those are caused by poor connections! (Just one under-tightened connector can course serious trouble in your network!).

18 Page 0629 0629 Text-TV Cabelcon Connectors Monday 18. October 1999 Node/ head-end Upstream Subscribers Intrusion of Man-made noise originates from Computers Computers Refrigerators Refrigerators Heaters Heaters Thermostats Thermostats TV-sets TV-sets Cellular phones Cellular phones - and from lots of other sources! Noise and unwanted signals will be added from all parts of the network. Noise from just one single subscriber can block the return path system completely! Upstream blocked Node/ head-end

19 Page 0631 0631 Text-TV Cabelcon Connectors Monday 18. October 1999 No chain is stronger than the weakest link - and the weakest links in a CATV network? Connections... - and there are thousands of them!

20 Page 0635 0635 Text-TV Cabelcon Connectors Monday 18. October 1999 Lets take a look at the most frequent connection problems...

21 Page 0637 0637 Text-TV Cabelcon Connectors Monday 18. October 1999 This is an example of a screw-on connector and a cable which have been exposed to salty moisture for just 300 hours: Heavy corrosion Metal in the cable is close to disappearing!

22 Page 0639 0639 Text-TV Cabelcon Connectors Monday 18. October 1999 - and the results of corrosion: Poor screening Poor return loss This will lead to.. Signal egress & ingress Intermodulation distortion Ghost pictures Loss of return path data Loss of forward signals Blocking at the node System downtime Expensive repair costs

23 Page 0642 0642 Text-TV Cabelcon Connectors Monday 18. October 1999 Lets take a look at PIM - Passive Intermodulation (CPID - Common Path Intermodulation Distortion) Moisture creates a layer of oxide between two different layers of metal (like a sandwich: Metal- Oxide-Metal). Oxidation creates a semiconductor effect (like rectifier diodes). Diodes act naturally as frequency mixers and multipliers.

24 Page 0645 0645 Text-TV Cabelcon Connectors Monday 18. October 1999 - and furthermore on PIM... Carriers present in the network will be mixed and multiplied by the sum and difference. All these new created and unwanted carriers (intermodulation) will appear at more or less unpredictable frequencies. PIM will be more visible below the FM-radio band (return path range) due to lower cable attenuation!

25 Page 0648 0648 Text-TV Cabelcon Connectors Monday 18. October 1999 PIM - Passive Intermodulation - schematic Two connector parts (or cable/connector parts) Mixing of carriers and frequency multiplication create many new carriers (PIM). Occurrence of diode effect through oxidation

26 Page 0652 0652 Text-TV Cabelcon Connectors Monday 18. October 1999 PIM, return loss and ingress problems grow at low frequencies (in return path band)... Cable attenuation is low (negligible). Almost no attenuation of reflected carriers caused by poor return loss. Frequency difference products (PIM) - caused by corrosion, are typically generated at low frequencies. Disturbance occurs in the return band. Considerable decrease in cable screening attenuation below 30 MHz. Extensive risk for ingress of unwanted signals and noise. Radiation will increase with poor return loss.

27 What happens? Page 0655 0655 Text-TV Cabelcon Connectors Monday 18. October 1999 Poor return Loss... Amplifier Coaxial Cable Corroded or badly installed connection Amplifier w/return path Reflected signals + upstream (return path) Forward signal Increased radiation Reflections and loss of wanted signals Increased bit error rate and loss of data or transmission speed!

28 Page 0657 0657 Text-TV Cabelcon Connectors Monday 18. October 1999 How can we prevent or minimise problems in the return path band? First of all through... Use of quality connectors Use of the right type of connector for your application. Use of quality cables with a high degree of screening. Proper installation practices. Lets see some more examples...

29 Two different types of crimp connectors - both manu- factured by Cabelcon - are mounted on a piece of cable. Both have been exposed to salty moisture for 300 hours in a chamber. Page 0660 0660 Text-TV Cabelcon Connectors Monday 18. October 1999 The result after inspection... This is a standard crimp connector for indoor use - and this is a moisture proof type for outdoor use! Darkened copper foil and braid. A pre stage to corrosion - through ingress of moisture. - You can see the difference! Poor return loss & PIM will sooner or later occur after a certain time with corrosion - while the cable installed with our moisture proof type remains unaffected!

30 Page 0663 0663 Text-TV Cabelcon Connectors Monday 18. October 1999 - and the same result can be seen on an UltraSeal compression connector

31 Page 0665 0665 Text-TV Cabelcon Connectors Monday 18. October 1999 - this applies to connections at all levels... - from the smallest drop connectors... - to the bigger trunk connectors.

32 Page 0675 0675 Text-TV Cabelcon Connectors Monday 18. October 1999 Precise installation is important! An example...

33 Page 0676 0676 Text-TV Cabelcon Connectors Monday 18. October 1999 Two cables - one prepared with a special tool, while the other one was stripped in the old fashion way, using a tube cutter. Visible difference: The outer conductor was 2 mm too short on the hand stripped cable Ordinary tube cutterSpecial preparation tool

34 Page 0677 0677 Text-TV Cabelcon Connectors Monday 18. October 1999 The result after installation and test... Measured return loss was two dB worse on the tube cutter stripped cable/connector. Just two dB? It could easily be more than two dB in each connector all the way from head-end to subscriber!

35 Page 0678 0678 Text-TV Cabelcon Connectors Monday 18. October 1999 Preparation tools Preparation tools - especially designed for the combination of your cables and connectors - will ensure a precise installation and... Prevent or minimise return path problems in your network.

36 Page 0679 0679 Text-TV Cabelcon Connectors Monday 18. October 1999 Finally some advise... Do not use screw-on connectors for professional applications. Choose the right type of connectors for your applications. Use moisture proof types (or heathshrink tube) for outdoor installations. Read and follow the manufacturers instructions for proper cable preparation and installation of your connectors. Use appropriate preparation tools - when available - for your connectors/cables to ease installation and to ensure optimal performance of your network.

37 Page 0680 0680 Text-TV Cabelcon Connectors Monday 18. October 1999 If you have any questions or require more information... - please visit our stand no. 438 This presentation can be downloaded from www.cabelcon.dk/ecc99.htm

38 Page 0685 0685 Text-TV Cabelcon Connectors Monday 18. October 1999 A Cabelcon production Presented by Jeremy Stubbs Copyright 1999 by Cabel-Con A/S All Rights Reserved

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