SEFRAM 7848B User Manual
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SEFRAM 7848B User Manual

Field strenght meter
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– 7848B –
7848B
FIELD STRENGHT METER
USER MANUAL
This product contains one or more programs protected under international and US copyright laws as un-
published works. They are confidential and proprietary to Dolby laboratories. Their reproduction or disclo-
sure, in whole or in part, or the production of derivative works there from without the express permission of
Dolby Laboratories is prohibited. Copyright 2003-2005 by Dolby Laboratories. All rights reserved.

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  • Page 1 – 7848B – 7848B FIELD STRENGHT METER USER MANUAL This product contains one or more programs protected under international and US copyright laws as un- published works. They are confidential and proprietary to Dolby laboratories. Their reproduction or disclo- sure, in whole or in part, or the production of derivative works there from without the express permission of...
  • Page 2 – 7848B – Revision follow-up Version / Date Modified chapters Nature of modification 1.0 / January 2020 Creation of the document...
  • Page 3 – 7848B – Thank you for purchasing this SEFRAM product and therefore trusting our company. Our different teams (research department, production, sales department, after-sales service…) are aiming at satisfying your wishes by designing and updating very advanced appliances. To obtain the best performance from this product please read this manual carefully.
  • Page 4 It shall subscribe, at its own expenses, any insurance required for the transport. The SEFRAM company reserves the right to refuse any product wrongly conditioned and not to take in charge any break con- secutive to the transport.
  • Page 5 March 1, 2015: Spare parts are not available to the consumer. SEFRAM offers the supply of spare parts during repair by its service. Consumable parts are provided according to the legislation applicable to them (case of batteries).

  • Page 6: Table Of Contents

    – 7848B – TABLE OF CONTENTS Important information ......................9 Particular precautions ............................. 9 Security instructions ............................9 Symbols and definitions ..........................9 Quick start-up ........................11 Presentation of the appliance ........................11 Signal spotting .............................. 12 2.2.1 Checking a terrestrial antenna ......................12 2.2.2...
  • Page 7 – 7848B – Autoset ................................. 42 Measures – TV – Spectrum.......................... 44 7.3.1 AutoLock function..........................44 Terrestrial setup: ............................45 Creation or modification of setups in the library ................... 45 Echo / Guard interval ............................ 46 Configuration ..............................48 Measures ..........................49 Setup modifications ............................
  • Page 8 – 7848B – 17 Technical specifications ....................80 17.1 Technical specifications ..........................80 17.2 Digital measurements ..........................81 17.3 Divers ................................ 83 17.4 General specifications ..........................84 17.5 Accessories .............................. 84 17.6 dBµV, dBmV, dBm conversion ......................... 85 17.7 Typical values for measurements ......................85...

  • Page 9: Important Information

     In case of failure or for the maintenance of the appliance, only a qualified personal shall be entitled to work on it. In such a case, it is required to use Sefram spare parts.  Do not open the appliance: risk of electric shock.
  • Page 10 – 7848B – Symbols on the appliance: Attention: Refer to the manual. Shows a risk of damage for the material connected to the in- strument or to the instrument itself. Ground: Grounded accessible parts. Product for recycling.

  • Page 11: Quick Start-Up

    Pour brancher le signal à analyser Important keys: The 7848B is an appliance with a capacitive touchscreen. This requires a soft handling. No glove and no sty- lus should be used, so that the triggering should be taken into account.

  • Page 12: Signal Spotting

    In this case, the Autoset function allows a scan of the channels that the antenna detects. Plug the cable of your antenna to the 7848B (take care to use an adequate adaptor) Turn on your appliance, then select terrestrial mode : The Home page appears on screen.

  • Page 13: Installation Of A Terrestrial Antenna

    – 7848B – Press START. The appliance searches until the end of the scan and turns directly to the Measures page. If no channel has been found, see the next chapter. On this new page, press Prog, select the channel that you want to display. Then you can press TV key to watch the image of the signal.

  • Page 14: Use Of The Spectrum

    – 7848B – 2.2.2.1 Use of the spectrum Plug the cable of your antenna to the 7848B (take care to use an adequate adaptor) Turn your appliance on. Press the Measures-TV-Spectrum key Press the Spectrum touch: Access to full SPAN mode...
  • Page 15 – 7848B – You can now display the level, the BER/MER of the signal selected on the same page by pressing the key.

  • Page 16: Use Of The Antenna Pointing

    – 7848B – 2.2.2.2 Use of the Antenna pointing The appliance gets an antenna pointing mode in order to regulate quickly and easily your terrestrial antenna. To access to the antenna pointing mode menu from the HOME page, press The following page appears :...
  • Page 17 – 7848B – Enter 4 frequencies of the emitter you want to check. You can find many different French transmitters on the website : https://www.matnt.tdf.fr/ Slowly orientate the antenna until hearing the locking melody and getting the best quality...

  • Page 18: Installation Of A Satellite Dish

    – 7848B – No transmitter found, bad reception quality → red smiley Average reception quality (< 50%) → orange smiley Good reception quality (> 50%) → green smiley 2.2.3 Installation of a satellite dish Connect the satellite dish to the appliance.
  • Page 19 – 7848B – Slowly orientate the satellite dish until hearing the locking melody and getting the best quality No found transponder → red smiley Average reception quality (< 50%) → orange smiley Good reception quality (> 50%) → green smiley...

  • Page 20: Presentation

    3 Presentation General -The field strength meter 7848B is an appliance designed for the installation and maintenance of any broad- casting and reception installations of analogical and digital terrestrial television channels or satellites. - The band ranges between 5 MHz to 2400 MHz; this allows accurate measurements on all analogical tele- vision standards, FM carrier waves and the various digital standards DVB-T/T2, DVB-S/S2, DSS.

  • Page 21: Description Of The Appliance

    – 7848B – Description of the appliance 7’’ capaci- tive Fas- touchscre tening for en high straps resolution RF input socket Remote supply light ON/OFF switch Ethernet socket USB A socket A/V input socket Charging indicator light External power socket...

  • Page 22: Power-Up

    Battery Attention: Any intervention on the battery requires the disassembly of the appliance and should be made by a SEFRAM technician. Use only batteries provided by SEFRAM. Security advice:  Do not throw into the fire or heat up the battery pack ...

  • Page 23: External Power Supply

    – 7848B – Charge the device only when the device is off. Charge the device only with the provided power supply block. The battery is 80%-loaded after 2 hours. The total charge is reached after 3 hours. The autonomy is defined in terrestrial mode with the lighting of the screen decreased, without remote-...

  • Page 24: Man-Machine Interface

    5 Man-machine interface Content of the screen 7848B is an appliance with a capacitive touchscreen. This requires a soft handling. No glove and no stylus should be used, so that the triggering should be taken into account. You will recognize the « keys » by their dark grey color (example: the home key: You can also select lines in tables.
  • Page 25 – 7848B – The Home page allows the navigation through all functions of the appliance: HOME Page in terrestrial mode HOME Page in satellite mode On all pages, we have this informations: Indication of the values Indication of the position of the...

  • Page 26: Changing Name Or Value

    – 7848B – To navigate through a table inside a page or a window, a vertical slide appears with arrows to move up and down the table. To move faster, you can slide a cursor with your fingers. Move up through...

  • Page 27: Change With Selection

    – 7848B – 5.2.2 Change with selection When pressing a key, you may have a window with multiple choice. You only have to press the value you want to validate it. This key allows you to cancel and exit this window, like in the example below: In this example, the bandwidth changes from 8 to 6 MHz: 5.2.3...

  • Page 28: List Of Setups

    – 7848B – List of setups In order to make easier the recall of data on field, the appliance uses 500 setups in satellite and 500 setups in terrestrial. Example of list of terrestrial setup Example of list of satellite setup A setup is made of: ...

  • Page 29: Satellite Mode

    – 7848B – 6 SATELLITE mode When the satellite mode is selected, a message appears with the request of starting Remote power supply of the satellite dish: Once the TV supply activated or not, the HOME page of the satellite mode appears:...

  • Page 30: Check Sat

    – 7848B – Check Sat Press to access Check Sat mode. Name and position of the satellite Global quality indi- cation Frequency, polarization, band, level and quality The appliance has 32 possible orbital positions for satellites. It is provided with near of 10 satellites regis- tered.

  • Page 31: Updating Satellite

    – 7848B – 6.1.1 Updating satellite You can update frequencies of the checks sat by consulting the file PDF posted on-line on the site web of SEFRAM. . You have to modify frequencies, following the previous paragraph and using the file updated monthly on the web site of SEFRAM.
  • Page 32 – 7848B – If the appliance is not synchronized on all four transponders, the quality indication is red. If the appliance is synchronized on all four transponders but the reception quality is aver- age, the quality indication is orange. Good reception quality (> 50%) → green smiley.

  • Page 33: Checking The Aligned Satellite

    – 7848B – 6.1.3 Checking the aligned satellite To check if you have aimed the right satellite, press the NIT key. The appliance searches the MPEG NIT table on one of the 4 transponders and displays the name of the satellite: Attention: The displayed name depends on the content of the MPEG NIT table.

  • Page 34: Autoset

    – 7848B – Autoset This mode allows an automatic research of setups and to provide information about the current place. You can access it through the key on page Home. A green check shows that the parameter is included in the research. If there is no green check, the parameter will not be taken into account for the research.

  • Page 35: Measures - Tv - Spectrum

    – 7848B – Any detected channel will be registered into the fist available setups of the library, starting from the end of the table. New found channels are added one by one into the first available setups of the library, starting from the end of the table Measures –...

  • Page 36: Autolock Function

    – 7848B – 6.3.1 Autolock function This function is design to lock on a digital signal (terrestrial, cable or satellite) You just have to enter the frequency or the channel (for terrestrial), then press AutoLock, The instrument will find automatically in few seconds the digital standard, the modulation type and all other parameters of the signal.

  • Page 37: Creation Or Modification Of Setups In The Library

    – 7848B – 6.4.1 Creation or modification of setups in the library To create or modify a setup in the library, you have to choose a line in the table. A window appears: Attention: If the line contains a setup, it will be erased. To cancel, press: You may erase the setup from the list by pressing the check to the left of the setup or to the setups you have to delete.

  • Page 38: Terrestrial Mode

    – 7848B – 7 TERRESTRIAL mode When terrestrial mode is selected, HOME page of terrestrial mode appears: We will see in the chapter different available menus you can access from HOME page. Remote supply is allowed pushing key : After, you can choose voltage level of remote supply :...
  • Page 39 – 7848B – Set your emitter name :...
  • Page 40 – 7848B – Enter 4 frequencies of the transmitter you want to check. You can find many different French transmitters on the website : https://www.matnt.tdf.fr/...
  • Page 41 – 7848B – Slowly orientate the antenna until hearing the locking melody and getting the best quality No found transponder → red smiley Average reception quality (< 50%) → orange smiley Good reception quality (> 50%) → green smiley Press...

  • Page 42: Autoset

    – 7848B – Autoset This mode allows an automatic research of setups and to provide information about the current place. You can access it through the key on page Home. A green check shows that the parameter is included in the research. If there is no green check, the parameter will not be taken into account for the research.
  • Page 43 – 7848B – Any detected channel will be automatically registered at the end of registered setups: New found channels are added one by one into the first available setups of the library, starting from the end of the table...

  • Page 44: Measures - Tv - Spectrum

    – 7848B – Measures – TV – Spectrum SPECTRUM mode full screen mode Autolock : Automatic search of setup Mode 7.3.1 AutoLock function This function is design to lock on a digital signal (terrestrial, cable or satellite) You just have to enter the frequency or the channel (for terrestrial), then press AutoLock, The instrument will find automatically in few seconds the digital standard, the modulation type and all other parameters of the signal.

  • Page 45: Terrestrial Setup

    – 7848B – Example for terrestrial (frequency 611MHz): For more information on measure page, see chapter Measures Terrestrial setup: Press allow you to access to the setup list: Creation or modification of setups in the library To create or modify a setup in the library, you have to choose a line in the table, a window appears:...

  • Page 46: Echo / Guard Interval

    – 7848B – You may erase the setup from the list by pressing the check to the left of the setup or to the setups you have to delete. Then click the basket and select the deletion of the selected setup: From this window, you can create a terrestrial setup.
  • Page 47 – 7848B – Pressing changes the horizontal scale (distance). Horizontal scale can be set in µs, km or miles by pressing Moving measurement arrow can be done by screen touch, or by automatic search keys The end of the guard interval is displayed with a yellow line.

  • Page 48: Configuration

    – 7848B – Yellow line, Main signal Guard interval limit Echos out of interval Pre-echo Measurements form arrow posi- tion Relative amplitude in dB and delay in µs (distance in km) from the main signal (0 pulse) can be measured.

  • Page 49: Measures

    – 7848B – 8 Measures Setup modifications The various parameters are:  The name of the setup  The frequency of the emitter or transponder (and the true frequency of satellite)  The standard and bandwidth for DVB-T/H and DVB-T2 ...

  • Page 50: Satellite Band

    – 7848B – Example in TNT : Signal level Signal/noise ratio of the signal The appliance makes different measurements according to the current standard. The other possible measurements are:  Average measurement  Peak measurement  Power measurement. The best is to be the closest possible of the green bar without exceeding it.

  • Page 51: Terrestrial Band

    – 7848B – Terrestrial band The appliance automatically makes level measurements on the Video carrier wave. The following table sums up the measurement types and the frequencies of the audio carrier waves for each standard: Standard Video carrier Measure Sound carrier...

  • Page 52: Digital Measurements

    – 7848B – Seuil min Seuil max Digital measurements In digital measurement mode, in addition to the RF level and to the C/N here above, the appliance also dis- plays the various BER (Bit Error Rate), the PER (Packet Error Rate) and the MER (Modulation Error Ratio) under DVB-T/T2, DVB-S/S2 or DSS.

  • Page 53: Dvb-T

    – 7848B – DVB-T REED DECODAGE VITERBI DEMODULATEUR TUNER SOLOMON MPEG BERi BERo Display of the measures of:  BERi: error rate before Viterbi  BERo: error rate after Viterbi  PER: error rate after Reed Solomon (error rate packet) ...

  • Page 54: Dvb-T2 / T2 Lite

    – 7848B – DVB-T2 / T2 Lite DECODAGE DEMODULATEUR LDPC TUNER MPEG BERo BERi Display of the measures of:  BERi: error rate before LDPC  BERo: error rate after LDPC  PER: error rate after BCH (lost packets) ...

  • Page 55: Dvb-S / Dss

    – 7848B – DVB-S / DSS REED DECODAGE VITERBI DEMODULATEUR TUNER SOLOMON MPEG BERi BERo Display of the measures of:  BERi : error rate before Viterbi  BERo : error rate after Viterbi  PER : error rate after Reed Solomon (error rate paquet) ...

  • Page 56: Dvb-S2 / S2X

    – 7848B – DVB-S2 / S2X DECODAGE DEMODULATEUR LDPC TUNER MPEG BERo BERi Display of the measures of:  BERi : error rate before LDPC  BERo : error rate after LDPC  PER : error rate after BCH (lost packets) ...

  • Page 57: Spectrum Analyser

    – 7848B – 9 Spectrum analyser Pressing SPECTRUM gives access to the SPECTRUM ANALYSER function. (graphical representation frequency / amplitude of the present signals in the input of the device) Satellite Terrestrial To swap from between satellite and terrestrial, go to Home page and press...

  • Page 58: Image And Sound

    – 7848B – 10 Image and Sound Pressing the TV zone gives access to the TV function. 10.1 Digital TV The name of the service and its main characteristics are displayed on top left of the screen.  720x576i: picture resolution 720 pixels / line, 576 lines, interlace ...

  • Page 59: Full Screen Mode

    – 7848B – 10.3 Full screen mode Pressing the key displays the image in full screen; only remain the battery level and the intensity + voltage of the remote power supply: To exit, you only have to touch the screen anywhere.

  • Page 60: Table Of Services

    – 7848B – 10.5 Table of services Pressing gives access to the list of services: This function allows selecting the channel you want to display. You only have to press the line you want.

  • Page 61: Lnb - Diseqc (Satellite Mode)

    – 7848B – 11 LNB – DiSEqC (Satellite mode) This page allows or not the activation of the remote power supply. In this page, there is the possibility to use normal mode or expert mode. Expert mode allows to carry out a larger number of parameters.
  • Page 62 – 7848B – Configuration line in normal mode: - LNB : LNB type and local oscillators LO1 (low band) and LO2 (high band) - LO selection: band commutation on the LNB (22kHz, ToneBurst or DiSEqC) - Polar selection: polarization commutation on the LNB (13/18V...
  • Page 63 – 7848B – 11.2 You must choose the type of NLB (parable head) present on your installation.  L band : no LNB head BIS frequencies (satellite intermediate frequencies) from 200 to 2400MHz no local oscillator frequency (OL)  C band :...

  • Page 64: Switches (Satellite Remote Power Supply In Expert Mode)

    – 7848B – 11.3 Switches 2-satellite switch 4-satellite switch * 22 kHz * DiSEqC Committed or Uncommitted * ToneBurst (MiniDiSEqC) *DiSEqC Committed ou Uncommitted Uncommitted 16-satellites switch * DiSEqC Committed + Uncommitted...
  • Page 65 – 7848B – Switch line Uncommitted line Satellite Position Commande DiSEqC Position Commande DiSEqC Pos A Option A + Position A Pos 1 Input 1 Pos B Option A + Position B Pos 1 Input 1 Pos C Option B + Position A...

  • Page 66: Positionner

    – 7848B – 11.4 Motorized Satellite dish control The appliance sends a DiSEqC command that triggers the rotation of a motorized satellite dish. In this example, the position is 2 (1 to 127 pre-loaded positions in the positionner) If the positionner is on No, it is deactivated...

  • Page 67: Dcss

    – 7848B – 11.5 DCSS Description: DCSS Digital Channel Stacking system: signal distribution system using frequency transposition. Used in satellite distribution for multiple or single dwelling, with several set top boxes. To give several receptors access to the whole spectrum and all polarizations, you need one coaxial cable per receptor and a suitable installation (multiple LNB, Quattro and multi-switches).
  • Page 68 – 7848B – The DCSS mode has priority on all other modes: selection polarization, selection OL, switches committed and uncommitted and positionner. 2 Modes : SATCR : Satellite Channel Router, standard EN50494 (or SCD, Unicable, …) Distribution of the satellite signal with only one coaxial cable to 2, 4 or 8 different receptors.

  • Page 69: Influence Of The Dcss On The Spectrum Analyzer

    – 7848B – SCD2 (EN50607) :  SLOT x: active Slot choice  CONFIG: access to each slot configuration Slots lists, frequencies, switches, PIN codes  INITIALISATIONS : 32 predefined slots  ALLOCATION : states of the 32 possible slots ...

  • Page 70: Configuration

    – 7848B – 12 Configuration For configuration, go Home page of terrestrial mode or satellite mode, then press configuration 12.1 Language You can select your language by pressing the « flag » (below). Press the flag corresponding to your language: 12.2...

  • Page 71: Frequency Map

    – 7848B – 12.3 Frequency map This key allows you to select the terrestrial frequency map of the appliance: 12.4 Update See chapter Software update for more details. 12.5 Factory recovery A complete set-up of the appliance under its FACTORY configuration, with confirmation...

  • Page 72: Configuration Import/Export

    You can make a backup on a USB stick of your setups of your appliance by pushing « « Configuration Ex- port ». And you can import from a USB stick this configuration with the touch “Configuration import”. You can also update checksat configuration available on SEFRAM’s website: https://www.sefram.com/downloads/maj_soft/fr/Sat.csv...

  • Page 73: Software Update

    The update requires an USB stick. To achieve the update: - Download the update file 784X_VX.X fichier zip on our website (www.sefram.fr) - Insert a USB stick on your PC - Unzip the file onto the root of the memory stick...

  • Page 74: Connection Of The Appliance To A Pc

    – 7848B – 14 Connection of the appliance to a PC The appliance has ETHERNET interface that make it possible to connect directly to a PC. For this type of connection, no driver is necessary. Connect your appliance to your PC by using a crossed ETHERNET cable (available in option with the num- ber 298504246 asking SEFRAM).
  • Page 75 – 7848B – Attention: If the PC has already been connected to Ethernet (network, modem…), it is necessary to reboot the PC before connecting your appliance. For the Ethernet connection of your appliance to a computer network, see the following scheme:...

  • Page 76: Displayed Messages

    – 7848B – 15 Displayed messages The appliance may display messages while working. 15.1 Alert messages Low battery: the appliance is about to shut off in a few minutes. Confirmation request for an important action. Remote power supply issue: cable under tension or excess intensity above maximum.
  • Page 77 – 7848B – Messages of the same king may show up; the pop up window is an alert; the corresponding message ex- plains the issue.

  • Page 78: Maintenance

    CONNECTIONS Erroneous measures At any measurement This "advice" does not engage the responsibility of SEFRAM. It guarantees the best possible use of the characteristics and the preservation of the product. Routine maintenance: The basic maintenance is simply cleaning the outside of the appliance. Any other operation requires a trained personal.
  • Page 79 100% good functioning pixels in the display zone. They specify a number of possible de- fective pixels at the surface of the screen. The SEFRAM quality service has preconditioned the mounting of the screen on your instrument to the re- spect of the acceptance conditions of the manufacturers.

  • Page 80: Technical Specifications

    – 7848B – 17 Technical specifications 17.1 Technical specifications Technical specifications Terrestrial band Satellite band Frequencies Range 5-1005 MHz 200-2400 MHz Resolution measure 50 kHz, display 1 kHz measure 1MHz, display 1MHz Level measurements Dynamic range 20-120 dBµV 20-120 dBµV Units dBµV, dBmV, dBm...

  • Page 81: Digital Measurements

    – 7848B – 17.2 Digital measurements DVB-T CBER (avant Viterbi BERi) Bit Error Rate (BER) VBER (après Viterbi BERo) UNC (paquets perdus PER) Modulation Error Rate(MER) 15 - 35dB Sensitivity < 35dBµV Bandwidth 6MHz, 7 MHz, 8 MHz FFT type...
  • Page 82 – 7848B – DVB-S, DSS CBER (before Viterbi BERi) Bit Error Rate (BER) VBER (after Viterbi BERo) UNC (lost packets PER) Modulation Error Rate(MER) 0-20dB Sensitivity < 47dBµV Symbole rate 1 to 50Ms/s Constellation QPSK Viterbi rate 1/2, 2/3, 3/4, 5/6, 7/8...

  • Page 83: Divers

    – 7848B – 17.3 Divers Remote supply Terrestrial Satellite 5V/13V/18 V/24V 13/18 V Tension 500 mA max (300mA for 24V) 500 mA max DiSEqC 2.1 control of dish motor DiSEqC switches committed & uncommitted bi-directionnal Mini DiSEqC (22kHz) 22 kHz, ToneBurst...

  • Page 84: General Specifications

    – 7848B – 17.4 General specifications LCD TFT 7 inch color 16/9, luminosity backlight 500 cd/m², 800x480 dots Display Touch capacitive External supply Main adaptator 110/230 VAC, with 5,5mm jack, 15 V 1 A Battery Batterie Li-ion 33W terrestrial DVB-T, no remote supply :...

  • Page 85: Dbµv, Dbmv, Dbm Conversion

    – 7848B – 17.6 dBµV, dBmV, dBm conversion  dBμV is a logarithmic ratio between a measured voltage Ud and a reference voltage Ur. The reference voltage is Ur = 1 μV N = 20 log (Ud/Ur)  dBmV is a logarithmic ratio between a measured voltage Ud and a reference voltage Ur.

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