Nautel XL12 Technical Instructions

Contents

12 000 WATT AM BROADCAST TRANSMITTERXL12Page 2-401 January 20022.1.6.1.2 When two audio sources are used, theyare both connected to terminals on the remoteinterface PWB. Exciter A's audio must beconnected between TB2-8(+) and TB2-9(-). ExciterB's audio must be connected between TB2-11(+)and TB2-12(-). The exciter interface PWB's AUDIOSOURCE switch must be set to DUAL.2.1.6.2 Both Exciters AM Stereo (External RFDrive): When both exciters are configured for AMstereo operation and the RF drive is being producedby an external AM stereo generator, the L+R audiofrom the AM stereo generator must be considered asa single source and connected between TB2-8(+)and TB2-9(-) of the remote interface PWB. Theexciter interface PWB's AUDIO SOURCE switch mustbe set to SINGLE.The audio must:- be a balanced 600 ohms.- have an output level which is between 0dBmand +12dBm for 100% modulation.- contain the left plus right (L+R) audioinformation required for AM stereo.2.1.6.3 One Exciter AM Stereo (External RFDrive)/One Exciter Monaural: When only oneexciter (either) is configured for AM Stereooperation using an external AM stereo generator asthe RF drive source, the other must be configured formonaural operation using its integral RF drive. Theleft plus right (L+R) audio from the AM stereogenerator and a monaural audio must be used andconnected to the appropriate exciter's audio inputterminals on the remote interface PWB [exciter 'A'audio to TB2-8(+)/TB2-9(-)/exciter 'B' audio to TB2-11(+)/TB2-12(-)]. The exciter interface PWB'sAUDIO SOURCE switch must be set to DUAL. The audioinputs must:- be a balanced 600 ohms.- have an output level which is between 0dBmand +12dBm for 100% modulation.- The audio for the AM stereo exciter mustcontain the left plus right (L+R) audioinformation.2.1.6.4 Exciter 'A' AM Stereo (Optional C-QUAM AM Stereo Exciter as RF DriveSource: When the optional C-QUAM AM stereoexciter PWB (A2A2) is installed as exciter A's RFdrive source, exciter 'B' may be configured for AMstereo or monaural operation from an external RFdrive source or for monaural operation from itsintegral RF drive. Exciter A's left and right audiomust be applied directly to terminals on the C-QUAM AM stereo exciter PWB [left audio to TB1-5(+)/TB1-3(-) and right audio to TB1-10(+)/TB1-8(-)]. The audio for exciter 'B' must be connectedbetween TB2-11(+) and TB2-12(-) of the remoteinterface PWB. The exciter interface PWB's AUDIOSOURCE switch must be set to STEREO.All audio inputs must be a balanced 600 ohms.Exciter A's left and right audio output levels mustboth be +10dBm for 100% modulation (left plus rightchannel).Exciter B's audio output levels must be between0dBm and +12dBm for 100% modulation.2.1.7 SAFETY INTERLOCKS: There arethree types of safety interlocks, one mechanical andtwo electrical. The mechanical interlock is a keycontrolled system that locks the rear door andprevents access to areas with high voltages whenAC power is being applied. One of the electricalinterlocks is an external circuit that inhibits the RFoutput if any of its serially connected switches isopened. The second electrical interlock is an internalcircuit that prevents the RF output from beingenabled if the ground wand has not been returned toits retaining clips after use.2.1.7.1 External Electrical Interlock: Theexternal electrical interlock circuit is connectedbetween TB1-26 (+24V INTLK) and TB1-25 (INTLKOPEN) of the remote interface PWB. When it is safeto produce an RF output, the circuit must be intactand apply +24V to TB1-25 (INTLK OPEN). When it isnot safe to produce an RF output (one or more of theexternal interlock switches have been activated), thecircuit must provide an open circuit to TB1-25 (INTLKOPEN). Any number of serial interlock switches maybe installed, provided +24V is removed from TB1-25if any interlock switch is activated.