TOTALLY SOLID STATE NON-DIRECTIONAL RADIO BEACONS khz

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2 TOTALLY SOLID STATE NON-DIRECTIONAL RADIO S khz This family of radio transmitters has been developed as extremely efficient, highly reliable Non Directional Beacons. ND2000A/4000A» MODULAR CONSTRUCTION» OPEN AND SHORT CIRCUIT PROOF» DUPLICATED MAIN/STANDBY TRANSMITTERS» ADJUSTABLE CARRIER WITH 0-95% MODULATION» OVER TEMPERATURE AND STANDBY SHUTDOWN» BETTER THAN 70% OVERALL EFFICIENCY AC IN TO RF OUT» IDEAL FOR UNATTENDED OPERATION IN REMOTE AREAS The transmitter output is fed via a 50 ohm coaxial feeder to a separate automatic antenna tuning unit (NX Series) to the Customer s antenna. ND2000A 500 W NX2000TUB ND4000A 1 kw NX4000TUB 2 kw NX8000TUB 3 kw NX16000TUB 4 kw NX16000TUB

3 At the top of the transmitter rack is the Control/Monitor Panel containing metering, indicating LED s and master controls for the transmitter. This panel hinges left to provide access to monitoring circuits and also to the harmonic filter which is located directly behind it. Below the Control/Monitor Panel, or in the adjacent rack, are the Main/Standby Beacon Power Subsystems, each capable of producing up to 1 kw with 95% modulation. These readily removable modules contain four (4) Class D Amplifiers and associated Pulse Width Modulators, a cooling fan and built in over-temperature protection. Next are separate Main/Standby Exciter Systems. Each Exciter system consists of three printed circuit board assemblies, namely a programmable electronic keyer, an audio processing board with a pulse width generator, and an RF oscillator board which provides an RF drive signal to the Class D Power Amplifiers via an RF Driver Subchassis. All of these are readily accessible for servicing or removal with the Exciter module pulled partially forward from the transmitter rack. Immediately below the Exciters is a main power ON/OFF panel. At the bottom of the transmitter racks are the Main/Standby Power Supply Systems. These are modular on the ND2000 and 4000 and may be withdrawn forward once the connections at the rear have been undone. The ND8000 to ND16000 models use 3 phase supplies with readily removable rectifier assemblies. ND2000/4000 NAUTEL s high efficiency series of NDB s utilize Class D Power Amplifiers and Pulse Width Modulation techniques.

4 Simply the best engineered transmitters CLASS D, SOLID STATE TECHNOLOGY EXTERNAL INPUT FILTER AMPLIFIER MOD DRIVER MODULATOR MAIN TRANSMITTER STANDBY TRANSMITTER LIMITER MODE SELECTION EMISSION MODE MULTIPLEXER PULSE WIDTH GENERATOR AMPLIFIER STANDBY CODE TIMING OSCILLATOR KEYER RF OSCILLATOR CODE GENERATOR TONE OSCILLATOR KEYING GATE RF DRIVE AMPLIFIER KEYED TONE EXCITER (SAME AS ABOVE) (SAME AS ABOVE) (SAME AS ABOVE) SERIES COMBINER CHANGEOVER RELAYS CHANGEOVER HARMONIC FILTER FWD PWR REFLD PWR RF PROBE CONTROL/ MONITOR PANEL RF OUTPUT EXTERNAL CONTROLS VISUAL ALARMS EXTERNAL ALARMS PARAMETERS FOR REMOTE MONITORING AC SUPPLY ON/OFF PANEL B SHEET 1 OF 1 V1 TO STANDBY TRANSMITTER RECTIFIER/ REGULATOR SUPPLY -48VDC BLOCK DIAGRAM ND SERIES NUMBER OF S: ND2000/4000A Signal generation commences in the Exciter where an audio tone is generated by an audio oscillator on the Keyer Board. This audio tone is then gated ON and OFF by a keying signal generated within the Keyer to provide a Morse code call sign for the NDB. THE KEYER FUNCTION Readily programmable by means of terminal blocks mounted on the printed circuit board» Repeated or periodic transmission of call sign» Provision for the insertion of a long filler dash or signal bit during silent period» Can increase space between characters» Can be used to generate standby codes Provides a 1, 2 or 3 letter Morse Code call sign» Dot length 125 milliseconds» Dash length 375 milliseconds» 64 bits in a frame» cycle time 8 seconds An external audio signal, e.g. for transmitting transcribed weather data or other information, may also be used. The audio input is fed separately into the audio board through low-pass and high-pass filters to define the bandwidth and through an audio limiter circuit to maintain an effectively constant level. The external audio signal may be transmitted with the ident tone signal in Voice and Beacon and is controlled by a push-to-talk function. These audio signals together with a DC level, which is varied by the carrier level control, then form the input to a pulse width generator where the information is converted into a PWM signal at the frequency of approximately 70 khz. This signal constitutes the Mod drive to the modulator portion of the Beacon Power Subsystem. An RF drive signal at the carrier frequency is generated and fed via an RF drive signal to the power amplifiers in the Beacon Power Subsystem.

5 In the Block Diagram shown up to four separate Beacon Power Subsystems are used, depending on transmitter power. Each amplifier is driven by a common RF drive signal from the Exciter. Their outputs are serially connected by means of a transformer to provide the final RF output. Similarly, the Mod drive signal is fed to four separate modulator subchassis where it is used to convert the 70 volt input supply to the required DC plus modulation to supply the four Class D power amplifiers in each Beacon Power Subsystem. Standard Options available for use with these Beacons include Direct Digital Synthesizers and variously configured Remote Control Systems. OUTPUT/REQUIREMENTS The RF Output is fed, via output changeover relays, to a common passive Harmonic Filter. This Harmonic Filter may be set at any frequency within the range of the transmitter. The filtered output signal is then fed via an output probe to provide the final transmitter output. Output Power is continuously adjustable from 100% to 20%. The Power Supply for each transmitter contains its own AC line transformer rectifier/regulator and smoothing choke. On the ND2000 and ND4000 an option is available to switch to battery in the event of AC line failure. An inverter in the power supply is used to obtain a +24 volt supply for the low level circuitry in the associated Exciter and Monitor. RF Terminating Impedance»»»» 50 ohms unbalanced ND2000, ND4000»»»» Type N Connector ND8000, 12000, 16000»»»» Type LC Connector ND2000A Carrier Power 500 W PEP 2000 W Power Requirements VAC 50/60 Hz Single 1.1 kw Max. Opt. 48 V-18 Amps DC ND4000A 1 kw 4000 W VAC 50/60 Hz Single 2.2 kw Max. Opt. 72 V-21 Amps DC 2 kw 8000 W VAC 50/60 Hz Three 4.2 kw Max. NA 3 kw W VAC 50/60 Hz Three 6.3 kw Max. NA 4 kw W VAC 50/60 Hz Three 8.4 kw Max. NA Both transmitters (main/standby) are monitored and controlled via common metering and control circuits. Metered functions include:» Forward and Reflected Power» DC Current Consumption on AC line or Battery» Percentage Modulation» All Supply Voltages» Continuous or No Keyed Tone/ Keyer Failure LED s and external alarms provide additional indications. Changeover between the Main/Standby transmitters is accomplished by relays in the RF output, and switching on the appropriate low level Power Supply. Operation of these relays is controlled by the monitor.

6 ND2000, 4000, 8000, 12,000, 16,000 These radiobeacons have all the features of a fully duplicated, main/standby system pair of transmitters. They are compliant with the specifications and recommendations ICAO Annex 10, Vol..1, Part 1, Section 3.4 SPECIFICATIONS Frequency Range khz determined by crystal Frequency Stability ± 0.005% or better over full environmental range Harmonic Levels Not exceeding -80 db relative to carrier when used in conjunction with a companion NX ATU into a standard antenna load. Emission Modes NON (CW) A2A (MCW Keyed tone) A2A and A3E (simultaneous telephony/beacon) External Audio Input Level -20 to +20 dbm across 600 ohms (balanced) Audio Response -3 db from 300 to 3000 Hz (A3E) Modulation Level Adjustable from 0 to 95% Audio Distortion Less than 3% at 95% modulation Hum and Noise Not exceeding -50 db relative to 1020 Hz, at a modulation level of 95% Internal Keyed Tone Frequency 400 or 1020 Hz ± 5% Keying Programmable electronic Keyer generating 1, 2 or 3 Morse letters at 7 words/minute. Sequence repeated at 8 second intervals Monitor Failure Thresholds Adjustable thresholds normally set so that changeover will occur if: a) Carrier Power reduces more than 3 db b) Modulation Power reduces more than 4 db c) Keying fails External or Remote Controls ON/OFF and Press-to-Talk Standby Test Select various standby codes Battery reset (ND2000, ND4000 only External or Remote Alarms Changeover or Shutdown High VSWR Battery Operation (ND2000, 4000 only) Environmental Limits -10 C to +55 C 0 to 95% relative humidity Altitude Up to 3000 meters (10,000 feet) All tests at full power into a 50 ohm resistive load unless otherwise stated MODEL WEIGHT(unpacked) SIZE COOLING & HEAT FLUSHING ND2000A ND4000A 257 Kg / 565 Lbs 280 Kg / 617 Lbs 166H X 57W X 61D CM. 65H X 22.5W X 24D IN. 166H X 57W X 61D CM. 65H X 22.5W X 24D IN. 90 CU. FT/MIN Forced Air 1,000 BTU/HR. MAX. 90 CU. FT/MIN Forced Air 2,200 BTU/HR. MAX. 454 Kg / 999 Lbs 504 Kg / 1109 Lbs 184H X 114W X 61D CM. 72H X 45W X 24D IN. 184H X 114W X 61D CM. 72H X 45W X 24D IN. 180 CU. FT/MIN Forced Air 4,400 BTU/HR. MAX. 270 CU. FT/MIN Forced Air 6,600 BTU/HR. MAX. 554 Kg / 1219 Lbs 184H X 114W X 61D CM. 72H X 45W X 24D IN. 360 CU. FT/MIN Forced Air 8,800 BTU/HR. MAX. For further information, please contact us at: Nautel Limited Hackett s Cove, RR#1 Tantallon, Nova Scotia, Canada B0J 3J0 Registered to ISO 9001 Phone: (902) Fax: (902) Nautel Maine Inc. 201 Target Industrial Circle, Bangor, Maine, USA Registered to ISO 9002 Phone: (207) Fax: (207) info@nautel.com or visit us on the Web at August 2000