MC-377 INSTRUCTION MANUAL LEVEL METER FOR ANALOGUE AND DIGITAL TV MC-377 1 GENERAL 1.1 Description The MC-377 is a compact, light-weight, portable instrument which offers installers all the basic functions needed to guarantee the good operation of analogue and digital TV installations. The instrument covers television bands, hyperband, cable television S channels as well as the satellite intermediate frequency band in K/C, up to 2050 MHz.
MC-377 INSTRUCTION MANUAL 1.2 Specifications TUNING VHF UHF SAT Resolution Frequency indication Display RF INPUTS Impedance Connector Maximum signal Maximum input voltage DC to 100 Hz 5 MHz to 2050 MHz MEASUREMENTS Types of measurements Terrestrial digital signals measurement Satellite digital signals measurement Sensibility TV bands Satellite band Reading Page 2 LOW VHF band (VLO) from 48.25 to 168.25 MHz HIGH VHF band (VHI) from 175,25 to 447.25 MHz UHF band, from 455.25 to 855.
MC-377 INSTRUCTION MANUAL Scales range IF bandwidth RF attenuators 60 dB for TV analogue signals 45 dB for TV digital signals 40 dB for SAT analogue signals 30 dB for TV digital signals 60 dB for C/N measurement 250 kHz (TV) and 18 MHz (SAT) TV bands: 50 dB in 10 and 20 dB steps Satellite band: 20 dB Total accuracy (25 ºC ± 5 ºC) TV bands ± 4 dB Satellite band ± 6 dB When carrying out level and power measurements it is necessary to apply the correction chart which is delivered with the instrument.
MC-377 INSTRUCTION MANUAL Spectrum Analyser Mode Bandwidth MAX mode SPAN mode SOUND Demodulation TV TER SAT Level indication Output power Volume control Built-in speaker EXT. UNITS POWER SUPPLY 22 kHz signal Voltage Frequency POWER SUPPLY Battery Voltage Autonomy Recharging time Protections Mains supply Voltage Frequency Consumption Page 4 Spectrum of the entire selected band, with a marker on the tuned frequency.
MC-377 INSTRUCTION MANUAL OPERATING ENVIRONMENTAL CONDITIONS Altitude Up to 2000 m Temperature margin From 5 ºC to 40 ºC Max. relative humidity 80% (up to 31 ºC), decreasing lineally up to 50% at 40 ºC. MECHANICAL FEATURES Dimensions Weight W. 280 x H. 95 x D. 250 mm (without carrying bag) 5.2 kg (battery included) INCLUDED ACCESSORIES Model Description AD-050 BNC/m-ANT/f adapter AD-051 BNC/m -F/f adapter DC-236 Carrying bag CA-005 Power cord CB-041 Rechargeable battery Pb 12 V / 2.6 Ah Fuse 3.
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MC-377 INSTRUCTION MANUAL 2 SAFETY RULES 2.1 General * Use this equipment connected only to devices or systems with their negative of measurement connected to ground potential. * This is a class I equipment, for safety reasons plug it to a supply line with the corresponding ground terminal. * This equipment can be used in Overvoltage Category II installations and Pollution Degree 2 environments.
MC-377 INSTRUCTION MANUAL * Symbols related with safety: DIRECT CURRENT ALTERNATING CURRENT DIRECT AND ALTERNATING GROUND TERMINAL PROTECTIVE CONDUCTOR FRAME TERMINAL EQUIPOTENTIALITY ON (Supply) OFF (Supply) DOUBLE INSULATION (Class II protection) CAUTION (Risk of electric shock) CAUTION REFER TO MANUAL FUSE 2.2 Specific precautions When using the equipment powered by the mains supply it is suitable to be out of its carrying case.
MC-377 INSTRUCTION MANUAL 3 INSTALLATION The MC-377 level meter is designed for use as a portable device. A carrying case is supplied to simplify transport and to allow the user to take measurements conveniently during the installation of the antenna. 3.1 Operating on the electrical mains supply Although the device was designed for use as portable equipment, it can also operate when connected to the mains power supply. Connect the device to the mains and press the start switch I/O [3].
MC-377 INSTRUCTION MANUAL 3.1.1 Selecting the mains operating voltage This equipment requires a mains power source of 110-125-220 or 230/240 V AC 50 to 60 Hz. Mains operating voltage can be selected at the mains base. Figure 1.- Selection of mains voltage. 1.- Pull out the fuseholder lid. 2.- Insert the fuseholder lid so the [A] pointer faces the desired mains voltage display [B]. CAUTION THE EQUIPMENT IS FACTORY SET FOR 220 V OPERATING VOLTAGE.
MC-377 INSTRUCTION MANUAL 3.2 Operating on the battery The MC-377 is a portable device powered by a 12 volt internal battery. Before taking any measurements, the battery charge must be checked. If the battery is low (a voltage lower than 11.2 V) colon sign (:) will appear blinking on the display of the frequency counter, under this circumstance the equipment must be connected to the mains to carry out the battery charge.
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MC-377 INSTRUCTION MANUAL 4 OPERATING INSTRUCTIONS 4.1 Description of the controls and elements Front panel Figure 2.- Front panel. [1] MONITOR [2] Noise Limit Luminous indicator showing detected noise level below meter noise level when measuring C/N. [3] I/O [4] STD L / BAND C On / Off key. Double function selector according on the active band. In terrestrial bands. Pressed key: it selects the "L" system. Released key: it selects B/G, I and D/K systems. In satellite band.
MC-377 INSTRUCTION MANUAL [5] MON./SPEC Operating mode selector: Pressed key (MON.): Monitor Mode. The monitor [1] shows the demodulated TV signal corresponding to the tuned frequency. Released key (SPECT): Spectrum Analyser Mode. The monitor [1] shows a frequency representation of the signal levels present in the band.
MC-377 INSTRUCTION MANUAL [19] SAT [20] DRAIN [21] TV RF signal input in terrestrial bands and external unit powering (antenna previous amplifiers) (0/13/18 V ± 22 kHz). [22] Digital frequency counter display Digital presentation of the tuned frequency in MHz. In the maximum bandwidth spectrum analyser operating mode (MAX) the digital frequency presentation is inhibited. [23] SPAN (Operational only in the variable bandwidth Spectrum Analyser mode -SPAN-).
MC-377 INSTRUCTION MANUAL [27] Audio control and activation of the measurement information over the image: Pressed control: Selects television sound demodulation and permits the volume to be altered, also: In Monitor mode it activates the measurement bar and the representation of the synchronism pulse. In Spectrum Analyser mode, SPAN mode, it activates the C/N measurement bar.
MC-377 INSTRUCTION MANUAL 4.2 Using the level meter 4.2.1 Start-up Press the I/O control [3]. The frequency counter display [22] will show the tuned frequency in MHz, except when the instrument is in MAX bandwidth spectrum analyser mode (SPAN/MAX key [6]). 4.2.2 Preliminary adjustments Connect the aerial signal to one of the inputs, TV [21] or SAT [19], depending on the band you wish to analyse: VLO/VHI/UHF or SAT.
MC-377 INSTRUCTION MANUAL 4.2.3 Spectrum Analyser operating mode The Spectrum Analyser operating mode enables you to be easily and quickly informed on the signals present in each band of the zone or region you are currently in. To select this operating mode, extract the MON./SPEC key [5] and an image will appear on the monitor similar to the one shown in the following figure. Figure 3.- Spectrum analyser mode, MAX mode.
MC-377 INSTRUCTION MANUAL In the complete band Spectrum Analyser mode (MAX, with the SPAN/MAX key [6] released) a white horizontal line will appear on the monitor (tuning mark) showing the tuning frequency (as can be seen in the previous figure). As you move across the frequencies with the TUNING control [24] you will see the mark move across the entire spectrum, allowing you to approximately pre-tune the frequency corresponding to the lobe that the mark is on.
MC-377 INSTRUCTION MANUAL 4.2.4 Monitor operating mode In the Monitor operating mode the MC-377 works like a conventional television. In addition, when the audio control [27] is pressed, you will see a horizontal bar at the top of the image whose length corresponds to the level/power of the tuned signal.
MC-377 INSTRUCTION MANUAL 4.2.5.1 Measuring the level of analogue signals To measure the level of an analogue signal, proceed as described below: - Select the Spectrum Analyser operating mode, SPAN mode, and with the help of the frequency counter display [22] tune the signal using the TUNING [24] and FINE TUNING controls [26]. Adjust the SPAN control [23] to select a bandwidth so that the signal occupies the most part of the image.
MC-377 INSTRUCTION MANUAL EXAMPLE A. Measuring the level of an analogue signal Take the following figure as an example, showing a television channel: the lower part of the spectrum shows the lobe corresponding to the video carrier (69 dBµV) and in the upper part you can see the audio carrier (63 dBµV) preceded by the chrominance signal (40 dBµV). Note that the measurements are taken on the LEVEL scale [33]. Measurement conditions: Video carrier freq.: 551.
MC-377 INSTRUCTION MANUAL 4.2.5.2 Measuring the power of digital channels The main characteristic of digital signals is that they distribute their energy across the entire channel bandwidth (in the same way as a noise signal), in other words they do not posses a differentiated carrier. Given this different nature from analogue signals the method used for measuring can not be the same.
MC-377 INSTRUCTION MANUAL EXAMPLE B.- Measuring the power of a digital signal Take the following figure as an example, showing a digital signal: Measurement conditions: Central frequency: 650.00 MHz RF attenuation: 0 dB Mode: DIGITAL Figure 7.- Example of digital channel power measurement. Using the CH POWER scale [32] (blue background) you can read a power of 45 dBµV. From the correction chart in figure 6, you obtain the Correction Factor to be applied to the frequency you are working with (650.
MC-377 INSTRUCTION MANUAL 4.2.5.3 Measuring the C/N ratio of analogue and digital signals Measuring the Carrier/Noise ratio provides us with information on the quality of analogue signals and the sturdiness of digital signals. The Spectrum Analyser operating mode, SPAN mode, enables this measurement to be made almost automatically.
MC-377 INSTRUCTION MANUAL EXAMPLE C.- Measuring the C/N ratio of an analogue signal Take the following figure as an example, showing an analogue television signal: Measurement conditions: Video carrier freq.: 520.25 MHz RF attenuation: 10 dB Mode: ANALOG Noise Limit indicator ON Figure 8.- Measuring the C/N ratio of an analogue channel.
MC-377 INSTRUCTION MANUAL 4.2.5.3.2 Measuring the C/N ratio of digital channels The C/N ratio of digital channels is measured in a similar way to analogue signals, but remember that for the instrument to interpret the signal as being digital you should select the digital signal measurement mode: simply, the DIG key [11] should be in the pressed position and the DIGITAL indicator [30] should remain lit. EXAMPLE D.- Measuring the C/N ratio of a digital channel Audio control [27] released.
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MC-377 INSTRUCTION MANUAL 5 MAINTENANCE 5.1 Operating recommendations One of the more common causes of breakdowns in TV signal level meters is the generation of internal short-circuits due to the introduction of small conductors. These conductors tend to be coaxial cable shielding wire, you are therefore advised TO NOT CUT COAXIAL CABLES OVER THE INSTRUMENT. 5.2 Fuses replacement 5.2.1 Mains fuse replacement The fuseholder lid is placed in the mains base and it is the voltage selector.
MC-377 INSTRUCTION MANUAL 5.3 Battery replacement The battery should be replaced when you notice that its capacity, once it has been charged, has decreased considerably (its mean life is of some 4 years). To change the battery follow next procedure. With the instrument off and disconnected from the mains: - Remove the securing screws from the upper and lower covers (6 screws on each cover). Remove the 2 covers. - Disconnect the battery connection terminals.
MC-377 INSTRUCTION MANUAL 5.4 Cleaning recommendations CAUTION TO CLEAN THE COVER, TAKE CARE THE INSTRUMENT IS DISCONNECTED. CAUTION DO NOT USE SCENTED HYDROCARBONS OR CHLORIZED SOLVENTS. SUCH PRODUCTS MAY ATTACK THE PLASTICS USED IN THE CONSTRUCTION OF THE COVER. The cover should be cleaned by means of a light solution of detergent and water applied with a soft cloth. Dry thoroughly before using the system again.
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MC-377 INSTRUCTION MANUAL APPENDIX A. DIGITAL TV SIGNALS Terrestrial Digital Television (abbreviated as TDT) uses COFDM modulation (Coded Orthogonal Frequency Division Multiplex) which possesses the main feature of immunity to multi-path reflections. Whereas the greater part of the power of an analogue channel is centred around the video carrier, digital signals distribute their energy across the entire channel bandwidth. This difference has important consequences when measuring the power of the channel.
MC-377 INSTRUCTION MANUAL MEASURING THE POWER OF DIGITAL CHANNELS As we have already mentioned, digital signals distribute their energy uniformly across the entire bandwidth of the channel, therefore measuring the power of digital channels depends on the channel Bandwidth or the Symbol Rate (the other modulation parameters do not affect this measurement). The MC-377 gives power measurements for digital channels under the precision specified for terrestrial signals of a bandwidth of 7.
MC-377 INSTRUCTION MANUAL TABLE OF CONTENTS 1 GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1 2 2 SAFETY RULES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
