Telex BTR-800, TR-825 dimensions Tech Tips, Frequency Interaction, Microphone Gain Adjustment

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Section

10

Tech Tips

Frequency Interaction

Unfortunately, radio frequency (RF) channels cannot be ran- domly selected for use in radio devices. They must be selected to avoid known frequencies in use, FCC restrictions on the lo- cation of devices, and even interference between your own RF devices. The factory defined frequencies (Groups 01A-24) se- lected by Telex for this RadioCom™ system are chosen to minimize possible interference.

Microphone Gain Adjustment

The microphone gain controls on the base station and beltpack are set to mid-levels by the factory. In most cases this setting w i ll w o r k f in e a n d o n ly o n lo u d s p e ec h w il l t h e overmodulation (OM) indicator light. However, in environ- ments where the background noise is loud or the user has a strong/quiet voice, the gain control will need to be adjusted. In Figure33 the gain is set correctly. The user’s root-mean-square (RMS) sound level is well below the OM threshold and only on peaks does his or her voice flash the OM indicator light.

Figure 34 displays the same gain setting as in Figure 33 but brought into a high noise environment. The user’s voice now lights the OM indicator all the time he or she speaks due to the higher noise plus the user speaking louder. The result on the system is distortion on louder speech. The microphone gain must be reduced. The same applies to a user with a powerful voice. If someone sets the system mic gain to their voice and user has a much stronger voice, then the gain will need to be reduced, even if the background noise is the same.

Always remember to set the microphone gain based on the sit- uation and location in which the equipment will be used. If the equipment is used on the field during a football game, set the gain based upon a loud stadium, NOT the quiet stadium 2 hours before a game. If a production studio user has a quiet voice, set the gain to their voice and NOT the stage hand’s loud voice who helped set up the system.

SOUND LEVEL, RMS

OM THRESHOLD

USER'S VOICE

NOISE

SOUND LEVEL, RMS

USER'S VOICE OM THRESHOLD

NOISE

Figure 33

Figure 34

Low Noise Environment

High Noise Environment

Microphone Gain Set Correctly

Microphone Gain Set Too High

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Contents JTN Telex Thank you for choosing RadioComTM Table of Contents Tech Tips General Description System FeaturesIntroduction BTR-800 Block Diagram WTA aControls and Connections Front Panel Local Headset WiringBTR-800 Base Station BTR-800 Front PanelControls and Connections Rear Panel BTR-800 Rear PanelBTR-800 Specifications OverallBlank TR-800 Top Panel TR-800 BeltpackControls and Connections Top Panel Headset Jack Wiring TR-800 Rear Panel/Connector/AntennasPush-to-Talk/Push-to-Transmit Switch LCD Liquid Crystal DisplayTR-800 Specifications Blank TR-825 Beltpack Telex RAAudio + Audio a Switched Headphone Ground TR-825 Rear Panel/Connector/AntennasTR-825 Specifications Blank BTR-800 Initial Equipment Set-UpUnpacking TR-800, TR-825Antenna Polarization Antenna PlacementAntenna Connection Distance between AntennasKeeping Site Clear to Antenna Distance Between base station and beltpackOperating System Near Obstructions Antenna Placement Improving Reception and Increasing RangeBase Station Set-up Power ConnectionTransmit Switches LocationInternal Transmit Switches Internal Transmit SwitchesIntercom Switch RJ-11 Type/ Four-wire PinoutRTS Distribution Panel TW5W Example Interface to an RTS TW SystemAudio Board Part Number and Dual Listen Component Locations Parts to be Removed by User to Enable Dual ListenDual Listen Functionality Auxiliary Input/Output Internal Auxiliary Input Routing SwitchAuxiliary Input Routing Switch Relay Contact Jack Adapter Screw Terminal Adapter Relay Output SchematicStage Announce / Relay Contacts Internal Stage Announce Level ControlBase Station Link Cable Base Station LinkTwo Stand Alone Base Stations Connected Together Battery Installation Beltpack Set-up Battery InstallationCharger and battery pack damage May resultTR-800 and TR-825 Rear Panel Transmit modeHeadset Connection Push-to-Talk PT Talk Recommended positionBlank Pre-Walk-Thru Checklist Blank System Quick Start System OperationFrequency Plan Overview Factory-Defined GroupsLocal Headset PowerBase Station Operation Intercom a and BDisplay Contrast LCD ContrastBTR-800 Menu Structure Main Screen Flowchart Beltpack Activity Code Definitions Power-Up ScreenOperating Screen SET Last Rx Changed Group / Channel SelectUP / Down Group / Frequency Select Frequency Edit User-Programmed Groups OnlyClearScanTM ClearScanSpecial Key Sequences Lockout 1st Use DefaultFactory Default CopyBeltpack Operation TR-800 and TR-825 Top and Rear PanelBeltpack Feature Enable/Disable Menus TR-800 Menu Structure Beltpack Menu StructureTR-800 Menu Structure Power-Up Screens Power-Up ScreensTR-800 Menu Structure Group / Channel Screen Group / Channel ScreenTR-800 Menu Structure Transmit Screen Transmit ScreenTR-800 Menu Structure Receive 1 Screen Receive 1 ScreenTR-800 Menu Structure Receive 2 Screen Receive 2 ScreenTR-800 Menu Structure ClearScan ClearScanTR-800 Menu Structure Stage Announce Enable/Disable Wireless Talk Around Enable/DisableTR-800 Menu Structure Audio Channel a or B Disable/Enable Talk Button Latch on/Latch offTR-800 Menu Structure Special Key Sequences Lockout 04A Scn TR-825 Menu Structure Beltpack Menu StructureTR-825 Menu Structure Power-Up Screens TR-825 Menu Structure Group / Channel Screen 704.700 TR-825 Menu Structure Transmit ScreenTR-825 Menu Structure Receive 1 Screen TR-825 Menu Structure Receive 2 Screen Ab SEP TR-825 Menu Structure Audio Output04b TR-825 Menu Structure ClearScanTMTR-825 Menu Structure Stage Announce Enable/Disable SA onTR-825 Menu Structure Wireless Talk Around TA bTR-825 Menu Structure Audio Channel a Options Audio Channel a OptionsTR-825 Menu Structure Audio Channel B Options Hold SET and Press B Continue to Hold SET Press B AgainTR-825 Menu Structure Special Key Sequences Lockout System Walk-Thru Blank Troubleshooting Problem SolutionBlank Frequency Interaction Microphone Gain AdjustmentTech Tips Blank TR-825 Battery InformationBattery Life TR-800 Blank Intercom Systems Specifications CommonBlank Accessories and Replacement Parts Blank Software License End-User License Agreement for Telex SoftwareBlank Certification Information FCC LicensingEU Declaration of Conformity PN 803257-1 Rev. H March Made in U.S.A