Hal Communications ST-6000 Instruction Manual Download

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ST-6000

FSK

DEMODULATOR

Summary of Contents for ST-6000

Page 1: ...ST 6000 FSK DEMODULATOR...

Page 3: ...plex Operation of the ST 6000 3 12 3 3 4 External Data Processing Equipment 3 15 3 3 5 External Oscilloscope Connections 3 15 3 3 6 Tone Keyer Control Connections 3 15 4 OPERATION 4 1 4 1 Front Panel...

Page 4: ...tart Data Output 5 5 5 2 7 Loop Keyer Stages 5 5 5 2 8 RS 232 MIL 188 Interfaces 5 6 5 2 9 KOS Circuit 5 6 5 3 Front Panel Indicators 5 6 5 4 Power Supply 5 7 5 5 Oscilloscope 5 7 5 6 Cabinet Wiring 5...

Page 5: ...ter Amp Lowpass Filter ATC 5 17 Figure 5 8 Tone Keyer 5 18 Figure 5 9 Slicer Antispace Autostart 5 19 Figure 5 10 Loop Drivers Loop Sense 5 20 Figure 5 11 RS 232 MIL 188 Interface 5 21 Figure 5 12 KOS...

Page 6: ...ision Threshold Hysteresis DTH circuit can also be switch selected to provide correction for multi path propagation distortion of the teleprinter signal CMOS digital circuitry is used to provide the a...

Page 7: ...provid ing the PTT line is derived from a positive DC source Since the KOS sensing line is connected to the rear panel it can also be triggered by external devices The audio input to the demodulator...

Page 8: ...ter 3 dB Bandwidth 850 Hz shift 1250 Hz all tone sets 425 Hz shift 775 Hz 170 Hz shift 275 Hz Discriminator filters 3 dB Bandwidth all tone sets 850 Hz shift 180 Hz 425 Hz shift 125 Hz 170 Hz shift 70...

Page 9: ...VDC maximum On 500 mA maximum Tuning Indicator X Y 1 diameter oscilloscope display rear panel connections for additional oscilloscope Automatic Threshold Control Performs DC level restoration to prov...

Page 10: ...Turns Decision Threshold Hysteresis circuit on or off PRINT LINE LOCAL LOCAL demodulator signals are inhibited to permit local operation KOS ON OFF Turns the keyboard operated switch sensing circuit...

Page 11: ...and key connection LOOP 3 Additional series loop connection that can be used with loop 1 or loop 2 KOS KOS control line Keyboard connection RS 232 MIL 188 Data input output connections for EIA RS 232C...

Page 12: ...hells 03 09 2031 6 3 pin male connector shells 03 09 1031 2 15 pin female connector shells 03 09 2152 60 male cable pins 02 09 2143 24 female cable pins 02 09 1143 2 0 5 ampere slow blow fuses 2 0 1 a...

Page 13: ...and the black the negative The shield of the cable is NOT con nected in the loop circuit but is connected to the ST 6000 cabinet The shield wire should therefore be connected to the cabinet of the te...

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Page 16: ...Note The data connection between the DS 3100 and the ST 6000 is via a loop connection not an RS 232 connection The RS 232 connector on the ST 6000 is only used to connect the CW ID line to the demodul...

Page 17: ...3 6 Figure 3 DS 2000 and ST 6000 System Connection Schematic...

Page 18: ...onnector J8 Connect a wire jumper between pin 1 Loop High and pin 4 Loop Low connect a second wire jumper between pin 3 Keyboard Data In and pin 5 Ground Use a six pin female shell and male pins 3 Plu...

Page 19: ...3 8 Figure 3 2 Loop Connections to the ST 6000...

Page 20: ...3 9 Figure 3 3 RS 232 I O Connections to the ST 6000...

Page 21: ...ansmitted signal When an electronic keyer is used the output circuit for cathode keying should be used instead of the grid block keying circuit In no case should the keyer reflect any negative voltage...

Page 22: ...em will usually clear up RF interfer ence When good RF grounds and low SWR feed lines are used the ST 6000 will work with even very high powered transmitter systems 3 3 Alternate Connections to the ST...

Page 23: ...nse emitter resistor and therefore may not pull down sufficiently when a high current load is switched 3 3 2 Separate Printer and Keyboard Connections As mentioned previously in section 3 2 6 the keyb...

Page 24: ...3 13 Figure 3 5 Alternate Loop Connections...

Page 25: ...3 14 Figure 3 6 Connections for the ST 6000 for Full Duplex Operation...

Page 26: ...y study section 5 and understand how the various sections of the ST 6000 operate and inter act before these connections are made 3 3 5 External Oscilloscope Connections The MARK and SPACE AC signals a...

Page 27: ...TONE ENABLE pin 12 J3 taking care to first remove the jumper between pins 8 ground and 12 of the AUXILIARY connector J3 In this case the KOS circuit will actuate the tone keyer output Figure 3 7 Conn...

Page 28: ...ussed in greater detail later in this section and in section 5 Tables 4 1 and 4 2 describe the front panel switches and indicators SWITCH POSITION FUNCTION POWER ON OFF Controls AC power to ST 6000 AU...

Page 29: ...us to try the ST 6000 without reading the rest of this manual 1 Use the standard cables and jumper plugs supplied with the ST 6000 to connect the unit to a receiver and printer or display as described...

Page 30: ...ift a bandwidth as narrow as 400 Hz can be used Two limitations should be kept in mind however the narrower the bandwidth the greater the frequency stability requirements on the receiver and wider ban...

Page 31: ...n also be adjusted for special sets of input tones between 1200 and 3000 Hz on special order 4 3 2 Receiver for AFSK Reception The receiver requirements for AFSK reception are not as exacting as those...

Page 32: ...es must match the discriminator filters fairly well for satisfactory autostart operation Most problems with AFSK autostart systems can be traced to either off frequency transmitter tones or misalignme...

Page 33: ...used only in the face of strong interference or very weak signals Use of higher gain directive receiving antennas will generally improve weak signal performance more than could be achieved with limite...

Page 34: ...xternal device in the loop The KOS is only allowed to turn on transmit mode when the loop interruptions are NOT caused by receive signals Thus the ST 6000 KOS circuit does not necessarily require sepa...

Page 35: ...itivity is set too close to the noise level false printing may occur on noise or interfering signals if set to too high a level the autostart may not trigger on all but the strongest signals with exac...

Page 36: ...at the RS 232 or MIL 188 data outputs are ideally conditioned for this application Since one is the in verse of the other the mark space sense or polarity can be changed by selecting either RS 232 or...

Page 37: ...on when properly aligned If the balanced modulator has not been recently readjusted the carrier rejection may well be no more than 25 to 35 dB Transmission of a small amount of carrier with a SSB voic...

Page 38: ...without reducing the transmitter power 4 13 3 Adjustment of the ST 6000 Tone Keyer The tone frequencies generated by the tone keyer are all derived from crystal oscillators and therefore do not requi...

Page 39: ...5 4 A total of three multiple feedback second order active bandpass filters are used in the ST 6000 each using of a MC 1458 operational amplifier The first filter using IC3a is tuned close to the mark...

Page 40: ...so rectified with 1N270 germanium diodes filtered and amplified in a type 741 operational amplifier I15 Since the polarity of the two di odes is the same the output of the amplifier is positive for ei...

Page 41: ...into a 500 Ohm load As on the ST 6000 input circuit a 500 Ohm isolation transformer is used on the tone keyer output to permit driving a 500 Ohm balanced load and to give DC isolation The on ly user...

Page 42: ...is is an adjustment that the user may wish to set to his own preference If the threshold pot is set too close to the noise the autostart will activate readily on noise and in terference if set too hig...

Page 43: ...ed on the AUXILIARY connector Transmit Loop Drive pin 13 and Receive Loop Drive pin 6 Either input can be used to drive the keyer stages with the reservation that the Re ceive Loop Drive input is also...

Page 44: ...2 or MIL 188 compatible outputs As suggested in section 3 these outputs can also be used to drive diode FSK circuits or devices such as the HAL RVD 1002 or RVD 1005 Visual Display Units Voltage or EIA...

Page 45: ...WER LED indicates presence of BOTH voltages The 175 Volt 60 mA loop voltage is derived from a full wave rectifier The LOOP fuse and cur rent limiting resistor are mounted on the cabinet The plus lead...

Page 46: ...are designed to permit quick removal for testing or replacement without unsoldering connections Figure 5 14 shows the cable listings for each interconnect cable used in the ST 6000 5 7 User Servicing...

Page 47: ...fore operat ing the unit This should include the auxiliary jumper plug J3 on the back of the 6000 to in sure that it is properly seated and all pins are making contact RCV Does the 6000 receive off th...

Page 48: ...that the passband of your transmitter is of sufficient width to pass both the Mark and Space tones you are using THERE ARE THREE WAYS TO SET THE ST 6000 FOR TRANSMITTING 1 KOS activated 2 Print switc...

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Page 67: ...e in stages starting with a partial reduction in exciter drive and ending with transmitter shut off Since RF energy can be induced in the demodulator or video ter minal circuitry through several diffe...

Page 68: ...should be placed as high as practicable Not only will this provide optimum reception but it will also reduce the level of RF in the shack all other factors being constant Excellent antenna installati...

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Hal Communications ST-6000, Instruction Manual

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