The Microma-MATV Aerial System Test Report (400kb pdf)
Contents
1. TEST REPORT Programmable Selective Amplifier Swiss Army Knife for the Terrestrial Antenna System When writing about antenna systems here in TELE satelite we usually mean the satellite antenna systems However most of us who use the satellite receivers do not resign from the conventional terrestrial reception After all quite often an interesting channel is transmitted for free in your region via the terrestrial transmitter This channel may be not available through satellite for example local news channel or be a part of a Pay TV satellite package New digital channels show up in the terrestrial TV what keeps it attractive Depending on the region you live you can receive the terrestrial channels with either a single dipole yagi antenna or you have to install a number of them pointing in differ ent directions In the latter case it is always necessary to combine the signals from a few antennae into one signal and send it down to the TV set In the family house such signal is usually distributed among many rooms In the block of apartments among many flats Combining the signal from different anten nae was usually done with a mixture of ampli fiers multiplexers and filters or traps For a regular mortal it was a kind of black magic what kind of equipment should he or she use and how to interconnect all components This kind of problem does not exist when you have a selective programmable amplifier from Spanish comp2. any Fagor Electronica The first products from that company appeared on the market already in 1992 The products offered now belong to the third gen eration Fagor Electronica designed and pro duced a family of products called MicroMATV pro models 100 100C 200C and 300C They differ in number of inputs and Automatic Gain E FAGOR MicroMATV pro 100 Control function To put it simply a selective programmable amplifier enables us to con nect a several antennae to one TV set or to one distribution cable network We took a closer look at the MicroMATV pro 100 model You can connect up to six dif ferent antennae for various bands You have the following inputs FM 87 5 108 MHZzO BI 47 68 MHz BIII DAB 174 230 MHz and 3 UHF inputs 470 862 MHz Unfortunately the model we tested had no SAT IF input 950 2150 MHz This input is available in models 200C and 300C However it had an auxil iary input AUX 47 68 130 862 MHz Using this input and the additional device of Fagor Electronica called DISAT 4 you can connect a satellite dish to the system Alternatively the AUX input may be used for some other TV or radio signal for example from another MicroMATV amplifier output or from an exist ing cable TV network Programmable Selective Amplifier TEST REPORT MOAT fl ol ce Fs ph m ae Lint ee Figure 1 shows the exemplary antenna system that Fagor Electronica provide in their user manual Not only can y
3. electronica es Phone 34 43 712526 Fax 34 43 712893 Model MicroMATV pro 100 Description Programmable Selective Amplifier Inputs FM BI BIII DAB AUX 3xUHF Number of programmable amplifiers filters in UHF band 10 Programmable filter bandwidth 8 48 MHz 1 6 channels Maximum gain 23 53 dB depending on band Input adjustment 23 25 dB depending on band Output adjustment 20 25 dB depending on band Noise factor 6 8 dB depending on band Output level 116 dBuV DIM 35dBc for FM 121 dBuV DIM 60dBc for other bands Power supply 230 Vac 15 Ambient temperature 0 50 C
4. er set to one channel bandwidth Fig 7 UHF filter set to six channel bandwidth Fig 8 Interaction between two adjoin ing 6 channel wide filters Still more passband ripple resulted when we tried to achieve more than 6 channel wide bandwidth by setting 2 adjoining filters on one UHF input We set the first filter for channels 21 26 474 514 MHz and the second filter for channels 27 32 522 562 MHz In such configuration one could expect a frequency response more or less flat for channels 21 32 474 562 MHz As you can see in figure 8 the frequency response was not perfectly flat It had peaks and dips Of course this will result in lower and higher amplification of different TV channels Fortunately the dif ference was not great and it should not pose any problem for the TV set to cope with such differences Fig 8 The gain setting for the UHF bands turned out to be very linear Every 5 step setting change resulted in almost exactly 5 dB change of the amplifier output Apart from the frequency response and gain setting we took a several measurements of signal to noise All of them showed almost no degra dation of S N ratio between amplifier output and input MicroMATV pro 100 is really a low noise amplifier Also all the practical tests with live TV signals showed absolutely no dis tortion or noise in the output of the device The MicroMATV pro programmable selec tive amplifiers have other practical fea
5. he actual changes were almost exactly 1 dB per step For settings between 20 and 25 it was about 1 5 dB per step Low ripple in the passband see figure 4 but the rolloff of 10dB 8MHz was not equally good as for the previous inputs Fig 4 Before dealing with the UHF bands we quickly checked the auxiliary input 47 68 130 862 MHz The flatness of its frequency characteristics was a nice surprise see figure 5 You should take into account that our noise generator had ca 5 dB decrease in amplitude at maximum frequency So the amplifier itself introduce maybe 1 or 2 dB difference in amplitude response over the entire band Fig 5 When we moved to the most interesting inputs UHF inputs the first observation was Fig 2 FM input frequency response Fig 3 BI input frequency response Fig 4 BIII DAB frequency response TEST REPORT Programmable Selective Amplifier that the rolloff of the filter is slightly worse compared to the previous fixed band inputs Although we got quite good 17dB 8MHz for the lower slope but only 9dB 8MHz for the upper slope of the filter When the filter was set to one or two channel bandwidth its fre quency response looked quite good but for the wider settings we observed a dip between 2 peaks in the passband Figure 6 shows a filter set for 1 channel and figure 7 shows filter set for 6 channels Fig 6 Fig 7 Fig 5 Auxiliary input frequency response Fig 6 UHF filt
6. ou con nect a number of antennae to the amplifier but also you have the possibility to adjust its amplification for different inputs And that s not all In the UHF bands you can set a number of filters so that to pass only a por tion of the UHF frequency spectrum 470 862 MHz In this way you filter out the part of band in which the TV channels that you want to receive are transmitted For example you may take channels Fig 1 Exemplary antenna system J Ej F E PF ia BE E e IEF LHF JF 20 25 36 37 and 55 60 from the first UHF antenna channels 40 42 and 63 65 from the second UHF antenna and channels 29 32 from the third UHF antenna You may set up to 10 different filters in UHF band The filter s pass through bandwidth can be individually set from a single channel 8 MHz to six chan nel 48 MHz MicroMATV pro 100 comes with an exter nal control unit used to enter all necessary settings and a power cord for 230Vac supply The unit itself is rather big and heavy and it is designed to be wall mounted in the indoors It makes an impression of a very solid piece of equipment Its workmanship leaves nothing to be desired The user manual that we got along with the unit was prepared in Spanish French and English Apart from the specifica tions it includes the programming guide At first we were somewhat afraid that it may be not that easy to enter all the neces sary settings but the reality was quite the m I
7. pi opposite The control unit with 2 line liquid crystal display and five buttons could not be simpler to operate It takes rather seconds than minutes to understand its logic For our tests we used the NG 281 noise generator and the Prolink 4C Premium spec trum analyzer of PROMAX Additionally we checked the operation of the amplifier with the real TV and radio signals of different fre quencies We started with FM band As you can see in figure 2 the filter amplitude response is practically perfect No passband ripple and very steep rolloff of 25dB 8MHz Filter covers exactly 87 5 108 MHz band Fig 2 The gain can be adjusted in 25 steps According to the specification the adjust ment range should be 25 dB We measured that actually the range is somewhat bigger 28 dB One step is roughly 1 dB The difference between specification and actual adjustment range was even bigger in BI band 47 68 MHz Instead of 25 dB adjustment range the actual range was 35 dB So we got something between 1 5 and 1 7 dB per one step While in practice greater range and coarser resolution of the gain adjustment should not pose any problem it is still a certain deviation from the published specification The frequency response for this input was as perfect as for the FM input Rolloff was about 20dB 8MHz See figure 3 Fig 3 BIII input 174 230 MHz was better with respect to gain setting For settings between 0 through 20 t
8. tures like Automatic Equalization System or Auto matic Gain Control AES when activated measures the signal at all inputs and auto matically sets the optimum gain setting for every band This is extremely convenient Without this feature the installer should either use something like spectrum analyzer to check the output level for every channel or group of channels or do it by trial and error AGC helps keeping the optimal output level when incoming signal changes in power for example due to weather conditions The amplifiers can automatically recognize the digital channels and keep their level 15 dB below the analog channel level Thanks to this DVB T receivers or digital analog TV sets work properly We can say that Fagor s selective amplifiers are really ready for today s mixed analog digital terrestrial transmissions Expert conclusion Very versatile replaces big number of classical devices like ampli fiers filters or multiplexers Easy programming AES function makes the necessary adjustments very simple Low noise Flat frequency response of the AUX amplifier Different sensitivity of gain setting dB per step on various bands Peter Miller TELE satellite Test Center Poland The rolloff of the upper slope of UHF filters could be steeper TECHNICAL DATA Manufacturer Fagor Electronica S Coop San Andres Mondragon Spain www fagorelectronica es E mail rf sales fagor
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