Testrapport Digitale kabelmeter SatCatcher Digipro C Max Professional Is bij vergelijking te verkiezen boven professionele meters Komt met veel nuttige accessoires voor de installateur Scherm dat zelfs in direct zonlicht makkelijk te lezen is Bevat ook tilt meting voor professionele installaties 34 TELE-satellite International The World s Largest Digital TV Trade Magazine 02-03/2012 www.tele-satellite.com www.tele-satellite.com 02-03/2012 TELE-satellite International The World s Largest Digital TV Trade Magazine 35
TEST REPORT Digital Cable Meter An Accurate Instrument With Many Accessories 02-03/2012 Satcatcher Digipro C Max More than a cable meter: includes everything a professional installer needs Accuracy is something that every installer will value with a signal meter but apart from that true professional users have further demands on a meter: the instrument should have a bright and readable display, and its keyboard should be easy to oper- ate. It should also offer a wide choice of accessories making the work simpler and more efficient. To our delight, the new Digipro C Max by Satcatcher fulfills all those requirements. Its display is exceptionally bright and clear, you can operate its keyboard even with gloves on your hands, and the number of accessories they offer to the professional user is really surprising. The meter can be supplied packaged in two ways. In a metal box like other Satcatcher meters or in a premium package with lots of extras included. For our test we opted for the latter and were delighted at the many useful accessories. The most unusual and most useful for an installer is a fully adjustable vest with a lot of pockets and straps. It allows you not only to transport and use the meter in a convenient way but also to keep handy all sorts of other tools an installer must have. Apart for the vest, you get a plug type power supply, a car lighter DC charger, a neck strap with a piece of sheep skin fur to avoid skin irritation, and a bad weather cover for the meter along with an attachable sun shade. Everything is neatly packed in a carrying bag so you do not need to worry that your meter accessories will disappear somewhere over time. The workmanship of the Digipro C Max is very good. The enclosure is robust but quite elegant at the same time. Buttons are large and clearly labeled. The POWER button has an edging around it what guarantees that the meter will not switch on accidentally when pressed against a solid surface. The keyboard consists of a numeric keypad, quick access buttons, navigational arrows and 4 function keys F1 - F4. The function of these F1 F4 buttons depends on the particular menu or screen you arrived at and is always explained at the bottom of the display window. Speaking of the display, it is one of the strongest points of this meter. This TFT LCD It is very bright and clear. You will be able to read it even outside in a very sunny day. There is also a loudspeaker embedded in the Digipro C Max Professional, giving off a significant sound volume. The Digipro Professional lets you either use a pre-programmed channel band plan or you may choose to blindscan the whole bandwidth. The effort you put into the initial channel band plan programming will pay off in much quicker measurements. To create a band plan, you enter the Meter Config menu and select Edit Channel item. In this screen, you edit the channel name (most of the installers would probably use the standard channel designators like: S02, S28, K32), its kind (analog or digital), and a number of parameters as: frequencies, modulation, symbol rate, bandwidth. Of course there is a different set of 36 TELE-satellite International The World s Largest Digital TV Trade Magazine 02-03/2012 www.tele-satellite.com
Table 1. Digital TV signal measurement results Power [dbµv] Power [dbµv] S/N [db] Signal Signal 256QAM 474 MHz 87,1 87,7 38,8 36,7 Video 471,25 MHz 61,3 64,4 23,7 48,6 26,1 17,7 64QAM 474 MHz 87,1 87,7 37,9 36,8 Audio 477,75 MHz 50,4 52 256QAM 674 MHz 82,5 83 39,4 35,6 Video 576,25 MHz 64 63,7 64QAM 674 MHz 82,6 82,8 38,7 35,4 Audio 581,75 MHz 50,3 49,8 parameters for analog and for digital channel. In this way, you edit channel by channel and save them in the meter s memory. Such a list of the channels that are present in a given cable network is called a band plan of this network. Once you have created a correct band plan for the cable systems you are about to install and measure, you can enter the Auto Measure menu item and make the meter measure every channel form the list one by one. However, it is also possible to scan an unknown network. In such case, the Digipro does a smart thing: it recognizes fully automatically all analog channels as well as the QAM modes and symbolrates for the digital DVB-C channels. For analog TV channels it shows the video and audio frequencies along with their signal levels and S/N ratio. The measurement results screen for a DVB-C signal is naturally more complex. You get not only signal frequency, QAM order, symbol rate, channel power, modulation error ratio (MER) and carrier-to-noise (C/N) readings but also a graphic representation of the constellation diagram. By pressing a button you can enlarge the diagram. This is perfect to asses the signal quality visually: the tighter the green dots concentration in the center of the squares, the less noisy the signal is. Of course, 38 Table 2. Analog TV signal measurement results MER [db] visual assessment is rather subjective and not very accurate, therefore there are MER and C/N readings that correspond to the quality of the digital signal. Furthermore, the Digipro offers a spectrum view. It produces a clean picture of the frequency spectrum with adjustable span and amplitude. You can set the following frequency spans: FULL, 500, 200, 100, 50, 32, 16, and 8 MHz. Maximum amplitude can be set from 60 to 120 dbµv in 10 dbµv steps. Digipro creates a very readable spectrum picture. It does not take long to scan the whole bandwidth. Even the best looking meter, and Digipro looks great indeed, would not be worth its price if its measurement results were improbable. Therefore, we compared the results produced by the Digipro with another high class reference meter. We are delighted to announce that the results were in perfect agreement. Please examine Table 1 and Table 2. Both for digital and analog TV signals, the channel power results were practically identical. Also the MER measurements were matching one another very well indeed. The only differences we noted in the S/N measurements, this, however, is common between different meter brands. That s because S/N measurements depend on the particular frequency a me- ter takes as a noise reference level. As a result, S/N and C/N can be compared only if measured with the same meter model but not when measured with different models and makes. MER is a much better signal quality indicator as this value can be measured with different meters and you can expect similar results with any product. Our general conclusion: Digipro CMax is a very accurate meter and you can fully rely on its signal strength and MER measurements. A great highlight is another positive feature: the Digipro not only takes measurements but it can also play back digital channel video and audio. Once it locks to the signal, it searches the NIT table inside the transport stream and based on the informations found there, the meter displays a list of TV and radio channels. The last remaining step is to select the channel you want to watch and press a button. Of course, this works only for FTA channels as the meter does not have any CI slot or smart card reader and can not descramble PayTV channels. The Digipro CMax does not display analog TV channels either but taking into account how fast the technology advances, analog channels will disappear from CATV networks anyway quite soon. So this is not something to care about. Finally we come to a truel- TELE-satellite International The World s Largest Digital TV Trade Magazine 02-03/2012 www.tele-satellite.com TELE-satellite expert Jacek Pawlowski wears the installer's vest from Satcatcher. The vest offers multiple pockets for the installer - and even matches the Digipro protective case' color! www.tele-satellite.com 02-03/2012 TELE-satellite International The World s Largest Digital TV Trade Magazine 39
1 40 2 3 TELE-satellite International The World s Largest Digital TV Trade Magazine 02-03/2012 www.tele-satellite.com 4 10 16 5 11 17 6 12 18 7 13 19 8 14 9 15 1. Main menu 2. Channel measure 3. Tilt measurement screen 4. DVB-C signal shown in spectrum view 5. Configuration menu 6. Band plans 7. One of the preprogrammed and plans 8. Editing a channel in a band plan 9. Options menu 10. Identifying digital TV signal chosen in the spectrum view 11. 256QAM constellation and signal measurement results 12. Closer examination of the constellation allows you to visually asses signal quality 13. Meter searches NIT in DVB-C signal to create a channel list 14. Channel list of the selected DVB-C carrier 15. Meter displays channel video like a small TV-set 16. A mix of analog and digital TV signal in a real cable network 17. Analog TV signals 18. Digital TV signals 19. Detecting the parameters of digital carrier www.tele-satellite.com 02-03/2012 TELE-satellite International The World s Largest Digital TV Trade Magazine 41
ly valuable function of the meter, which is so useful for the professional installer: the tilt measurement. Up to ten channels can be selected for this. Usually, you would select channels evenly distributed over the whole frequency range. Of course, the selected channels must carry a TV signal. You first measure those channels in the TILT Measure submenu somewhere in the beginning of the cable network, where all the signals are strong and relatively equal in amplitude. then you press the REF button to store those channels levels as reference. Then you move to various other points of the network and repeat this measurement. You will see the difference expressed in decibels between the reference level and the current level for every channel. The tilt measurement allows you to quickly identify signal level differences over a specified frequency range. Then all you do is insert an attenuator or an equalizar in order to smoothen the differences according to the cable system s specifications. Thanks to this, you can easily find out if the cabling along with the distribution equipment does not introduce excessive attenuation in particular parts of the cable TV frequency range. We found the Digipro C- Max to be a very mature meter, offering to the installer all the features he needs to properly align a cable system. The accuracy of the meter matches our professional reference meters and the accessories made available by Satcacther are an additional value to the installer. Manufacturer Webpage E-mail TECHNICAL DATA SatCatcher Ltd, Unit 7, Salvesen Way, Hull, East Yorkshire, HU3 4UQ, UNITED KINGDOM www.satcatcher.com sales@satcatcher.com Tel +44-1652-408191 Model Function Input frequency range Input signal level range Accuracy of level measurement DVB-C symbol rates Modulation Digital TV standard Channel bandwidth Working time when fully charged Digipro C Max Digital and analog cable TV meter 46 MHz - 862 MHz for digital TV 46 MHz 870 MHz for analog TV 40dBuV - 110dBuV for digital TV 25dBuV 120dBuV for analog TV 2 db for digital TV 1.5 db for analog TV 1 7 Ms/sec 16/32 /64/128/256QAM DVB-C/ITU-T J.83-ANNEX A/B/C 4, 8, 20, 40 MHz, USA version: 6 instead of 8 MHz 4 5 hours Expert Opinion + Exceptionally accurate Very bright and clear display A lot of useful accessories USB application available for editing band plan none Jacek Pawlowski TELE-satellite Test Center Poland 42 TELE-satellite International The World s Largest Digital TV Trade Magazine 02-03/2012 www.tele-satellite.com