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ft.757gx ]i hf all mode computer aided transceiver

1. Data 2 5 Selected Memory Channel No 0 9 6 9 Operating Frequency BCD 3 10 Selected Mode 11 14 Frequency BCD 3 15 VFO A Mode 16 19 VFO B Frequency BCD 3 20 vFO B Mode 21 24 Clarifier Frequency BCD 3 25 Clarifier Mode 26 29 Memory Channel 0 Frequency BCD 3 30 __ Memory Channel 0 Mode 31 35 Memory Ch 1 same format as 26 30 36 40 Memory Ch 2 same format as 26 30 41 45 Memory Ch 3 same format as 26 30 46 50 Memory Ch 4 same format as 26 30 51 55 Memory Ch 5 same format as 26 30 56 60 Memory Ch 6 same format as 26 30 61 65 Memory Ch 7 same format as 26 30 66 70 Memory Ch 8 same format as 26 30 71 75 Memory Ch 9 same format as 26 30 Indicates position of with the same name front panel switch Byte values are those indicated for Modes in the Instruction Code Chart Calculate Memory Channel addresses by Channel Freq Index Ch No x 5 26 Channel Mode Index Ch No x 5 30 TABLE 1 TABLE 2 BAND DATA Byte Frequency Value Range MHz 01 below 2 5 02 2 5 4 0 03 4 0 7 5 04 7 8 10 5 05 10 5 14 5 06 T4 5 5 1825 07 18 522 21 5 08 21 5 25 0 09 25 0 30 0 high end of each band range is actually 10 Hz below the freq shown STATUS FLAG BITS 27126 25 23122121129 L Split 2
2. 2030 RSTAT INT RXRDY 2 RSTAT2 RXRDY 2 2040 IF RSTAT1 RSTAT2 THEN 2010 2050 RETURN REM Check serial port input status REM 0 to 15 REM Return to menu POKE IOPORT INST REM Get USART Status REM Rotate RxRdy flag bit 1 to bit 0 REM Check if Odd set or Even reset REM Loop until it is set RECEIVER FRONT END PROTECTION The receiver front end in FT 757GXII includes vacuum arc surge suppressor and a lamp fuse to protect the sensitive receiver circuitry from high voltage pulses EMP at the antenna terminal Several thousands of volts can dev elop naturally when dry wind or electrical storms create an electrostatic charge on the antenna elements and this is delivered to the antenna jack if the antenna is connected to the transceiver In such a case the lamp fuse may burn out even if the transceiver is turned off at the time The only way to avoid this condition is to disconnect the antenna from the transceiver whenever the weather is likely to create high voltage on the antenna the feedline should be connected to ground to allow the charge to dissipate If the receiver is found to have suddenly lost sensitivity inspect the filament of the lamp fuse F1001 on the RF Unit If it is open try to determine the cause of the overvoltage eg was the antenna left connected during electrical storm or dry windy weather since you last used the equipment To obtain re placement lamp fuses ask
3. 26 mitted signal Select 158 USB mode and set the PROC switch off The PTT jack on the rear panel may be used for external transmit receive control press the VOX button to allow automatic transmit receive switching either full or semi break in may be used Manual transmit receive control is also possible with the MOX button Note that the displayed frequency is the sup pressed carrier frequency so your actual MARK and SPACE frequencies will be displaced from the display by the audio frequencies of the tones Use the MIC gain control to adjust power out put while transmitting for full power set the MIC gain so that the meter showing ALC deflects slightly Reduce power output by turning the MIC gain counterclockwise from full power and observing power output on the PO meter after calibrating as described pre viously or on an external wattmeter As mentioned previously the FT 757GXII is capable of full power AFSK transmission for limited periods when used with a heavy duty power supply Restrict transmissions to 30 minutes with the FP 757HD If using the FP 700 restrict RTTY or packet power output to 50 watts maximum However if the air temperature is high or at high altitudes cooling efficiency is decreased and so power output should be reduced accordingly Also it is a good prac tice to back off on the power whenever making a long transmission and even then supply tem perature should be closel
4. 0 150 OR FREQ gt 29 99999 THEN PRINT Out of Range Re enter Freq GOTO 310 REM Split FREQ into pairs of decimal digits FREQ FREQ 10000 REM Convert to Integer 10 s of kHz MHZ INT FREQ 100000 REM 100 5 and 10 s of MHz MKHZ INT FREQ 1000 MHZ 100 REM 1 of MHz and 100 s of kHz KHZ INT FREQ 10 MHZ 10000 MKHZ 100 REM 10 s and 1 s of kHz LMHZ MHZ 100000 LMKHZ MKHZ 1000 LKHZ KHZ 10 REM Convert back to long value HZ FREQ LMHZ LMKHZ LKHZ REM Subtract larger digs leave 100 s amp 10 s of Hz INT HZ 0 5 10 REM Round it up REM Convert Decimal digit pairs into BCD Parameters Pi INT MHZ 10 16 MHZ INT MHZ 10 10 P2 INT MKHZ 10 16 MKHZ INT MKHZ 10 10 P3 INT KHZ 10 16 KHZ INT KHZ 10 10 INT HZ 10 16 INT HZ 10 10 INST 10 GOSUB 1000 GOTO 100 REM Instruction Set Freq Send to xcvr and loop Set Instruction and Parameter for other commands THEN INST 12 P1 0 REM Instruction Set Mode P1 lsb THEN INST 12 Pl 1 s REM Instruction Set Mode P1 usb THEN INST 12 P1 2 REM Instruction Set Mode cw w INST 12 1 REM Instruction Set Mode P1 cw n F INST 12 P1 REM Instruction Set Mode P1 am IF y INST 12 P1 REM Instruction Set Mode P1 fm I
5. FT 757GX1 HF ALL MODE COMPUTER AIDED TRANSCEIVER GENERAL DESCRIPTION The FT 757GXII combines the finest features of its famous predecessor the FT 757GX with new developments in response to technological advances and to the most popular requests from serious hf operators New advances in digital trol and computer aided manufacturing methods allow the FT 757GXII to offer great versatility and operator convenience on all modes and all hf amateur radio bands with 100 watts of PEP transmitter power output on the amateur bands and general coverage reception from 0 15 to 30 MHz Special new digital features include operator selectable mode dependent tuning steps ten memory channels which store mode as well as frequency auto resume loop scanning between dual VFOs or adjacent memories a special clarifier memory and an improved CAT Computer Aided Transceiver System for simplified programming and more advanced control by an external computer A 40dB IF Notch filter is provided along with continuously adjustable IF Shift for minimizing interference during SSB CW and ECSS reception of AM signals Wideband AM and narrowband CW IF filters are included as standard switch able RF amplifier and 20dB attenuator are provided to optimize sensitivity and dynamic range on all frequencies under a wide variety of conditions while the noise blanking pulse width can be set on the front panel continuously adjust able from narrow ignition
6. LSD MSD Frequency Parms Notice that for frequency parameters the 100 MHz digit must be present and set to zero for frequencies below 100 MHz Also notice that decimal frequency data must be translated into BCD binary coded decimal digits for sending and that the LSD least significant digit Parameter 4 100 s and 10 s of Hz is sent first Return Delay and Read Status Commands All but two of the Instructions are uni directional from the computer to the trans ceiver only The bi directional instructions are the Return Delay and Read Status commands which have no effect on operation of the FT 757GXII except to cause it to return current operating status information on the SO Serial Output pin 2 line to the computer after a specified delay This data allows the compu ter to check the status of the transceiver and so the program should send one of these commands to verify the transceiver state after each series of instructions Also the Read Status command is sent with a 01 parameter to read the digitized signal strength indication 0 to OFh CAT SYSTEM TIMING CHART Data Byte START po D2 D4 D5 D6 D7 STOP BITS BIT 2 5 byte Command Parm 4 Parm 3 Parm 2 Parm 1 Instruction Block LSD Code MSD 100ms MAX 302 After the Return Delay or Read Status commanc has been sent the transceiver will wait for 0 to 255 ms as
7. vfo Mem vfo Tx Rx Gen Ham not used TABLE 3 Dial Lock Clarifier 0 oooooo OFF unlkd OFF Smplx OFF vfo opratn receiving Gen Steps 1 1 1 A selected 1 1 1 1 FREQUENCY DATA ON locked ON Split tx rx ON vfo B selected memory operation transmitting Ham Band Steps Frequency digits appear in the data stream as binary coded decimal BCD hex adecimal representation of decimal digits with leading zero fill to the 100 s of MHz digit Bytes are send in reverse order as described earlier and again in the following example EXAMPLE 072 34567 MHz Index Index Freg Index Freq Index TS 4 E 3 2 1 0 01h 23h 45h 67h 10 20 30 40 50 60 100 110 120 130 140 150 160 170 180 190 200 210 220 300 310 320 400 410 420 430 440 450 460 470 480 490 500 510 520 530 600 610 620 640 650 660 670 680 690 700 800 810 820 TEST PROGRAM LISTING Following is a listing of a BASIC program developed on an Apple computer using a Yaesu FIF 65A CAT Interface Unit which tests a number of the CAT System functions in the FT 757GXII The program has been intentionally simpli fied so that it might easily be converted for use on other computers with other serial i o systems and with other variations of BASIC As such it is not useful a
8. ORANGE TE noun 3 E 1 GREEN 2 YELLOW 4 BROWN Viewed ton 8 5 ORANGE 6 REO 7 BLACK 7 SLACK PLUG CONNECTIONS SD Sg ee Shield braid Signal or Control to center pin ground gt RCA Plug Htm __ Center Conductor Stereo Headphone Plug Automatic Keyer Paddle Plug CAT Mini DIN Plug dg e OPERATION Before plugging the power supply into the wall outlet in base installation ensure that the power supply is wired for your AC line vol tage Make certain that the proper fuse is installed and that it is properly connected to the transceiver as described in the Instal lation section Also make sure the antenna and ground are connected Refer to the Memory Backup information below to enable the backup Connect a microphone if desired to the MIC jack See page 17 for microphone information For CW operation connect keyer paddles or a CW key as shown on page 17 to the KEY jack on the rear panel Preset the POWER switch off and all push buttons to the undepressed position Set the other controls as follows MIC fully counterclockwise DRIVE fully counterclockwise AF fully counterclockwise RF fully clockwise NOTCH fully counterclockwise into the OFF clickstop SHIFT 12 o clock position NB 12 o clock position Initial Power Up and Tuning Make sure that the MOX and VOX buttons are in the undepressed out position
9. for the FL 7000 or for low power and light duty applications All power supplies can be wired for 100 110 117 200 220 or 234 VAC FT 757GXII Duct Flow Cooling System Cooling Fan Exhaust Outlet PA Unit Heatsink Fins X 7 LU Ll amp AA E CES I EEEL rz j I II T c I i pem jw pei mj wo Fan Motor Shield Plate Local Unit Chassis RF Unit SPECIFICATIONS TRANSMITTER Frequency range 160m band 1 5 to 1 99999 MHz 80m band 3 5 to 3 99999 MHz 40m band 7 0 to 7 49999 MHz 30m band 10 0 to 10 49999 MHz 20m band 14 0 to 14 49999 MHz 17m band 18 0 to 18 49999 MHz 15m band 21 0 to 21 49999 MHz 12m band 24 5 to 24 99999 MHz 10m band 28 0 to 29 99999 MHz Tuning steps selectable SSB amp CW 10 Hz or 1 kHz step AM 1 kHz or 10 kHz step FM 2 5 kHz or 10 kHz step Emission types LSB USB J3E CW AM and FM G3E Power output SSB CW amp FM 100W PEP DC with slightly less on 10m band AM 25W Carrier SSB Carrier suppression better than 40dB below peak output Unwanted sideband suppression SSB better than 50dB below peak output 1 kHz tone Spurious radiation better than 50dB below peak output Audio response less than 6dB from 350 to 2900Hz 3rd order in
10. 100 110 117 200 220 or 234 VAC However before connecting any power supply to the transceiver or AC line make certain that the supply is properly set up for the local line voltage and that the correct fuse in installed The FP 757HD is a heavy duty series regulator power supply capable of 50 duty cycle opera tion with full power transmissions for up to 30 minutes at a time Forced air cooling is provided over an extra large internal heat sink The FP 757HD requires a 6 amp fuse for 100 110 or 117 VAC or a 3 amp fuse for 200 220 or 234 VAC Power transformer primary connections for the different line voltages are shown on the next page The FP 700 power supply may be used for light duty operation with the FT 757GXII CW SSB or reduced power FM and AM AC voltages fuse requirements and power transformer wiring are the same as for the FP 757HD as described above and shown in the diagram on the next page but the plastic sleeve on the supply DC cable must be cut to allow connection to the speaker in the power supply NEVER CONNECT AC POWER OR DC ABOVE 15V DIRECTLY TO THE FT 757GXII Make certain that the POWER switch on the front panel of the FT 757GXII is OFF out before connecting power to the transceiver and double check to make sure that the polar ity of the connections is correct before swit ching the transceiver on as FP 757HD Equipment Location and Grounding In all base station installa
11. POWER switch on the trans ceiver is OFF and connect the DC cable to the transceiver The diagram below shows the plug pin connections The posi tive RED wire must include a 20 amp fuse installed in the supplied cable Always check to ensure that this switch is OFF before starting the engine FUSE Ratings 20A for FT 757GXII for FT 757SXII Mobile Antenna Installation Please review the base station antenna information on the previous page An antenna tuner such as the FC 757AT is particularly desirable in a mobile station where the short antenna elements have very narrow bandwidth Make sure that the shield of the antenna coax is firmly grounded to the car body at the antenna feedpoint Mounting The optional MMB 20 Mobile Mounting Bracket for the FT 757GXII allows quick insertion and removal of the transceiver from the vehicle Complete instructions are provided with the bracket which may be installed either above or underneath the transceiver see photo FUSE 6A FT 757SXII 20A FT 757GXII TERMINALS 1 BATTERY TERMINALS 3 1 FUSE HOLDER DC Power Cable Connections MMB 20 Mobile Mounting Bracket c dns INTERCONNECTIONS Linear Amplifiers The FT 757GXII includes a high voltage 150V transistor switch capable of handling up to 1 5 amperes DC to control transmit receive switching of a linear amplifier via pin 6 of the BAND DATA jack However
12. VOX system make the above adjustments with the AF control set for low volume Then in crease the volume to the desired operating level and adjust the ANTI TRIP control on the rear panel just to the point where receiver audio from the speaker ceases to trip the VOX Clarifier Receiver Offset When receiving on a vfo the CLAR button can be pressed to allow independent tuning and mode changing of the receiver without affec ting the transmit frequency CLAR is displayed to the left of the operating frequency This feature is useful if after making contact with another station his transmitter drifts you can retune his signal without changing your own transmitting frequency Also since the range of the clarifier is unlimited it can be used for split frequency operation While the clarifier is on the tuning knob and mode selector affect only the receiver the transmitting frequency and mode will remain the same as before the clarifier was acti vated and this frequency and mode will be displayed when transmitting The FT 757GXII incorporates a special clari fier memory which allows you to listen on the transmit frequency by switching off the clarifier As long as you don t touch the tuning knob pressing CLAR again returns you to the offset receive frequency When the contact is finished remember to switch off the clarifier so that the transmit and receive frequencies and modes will be re aligned when you retune CW
13. and even then supply tem perature should be closely monitored After transmitting if the cooling fan is on don t turn the POWER switch off until the set has had a few minutes to cool and the fan to switch off e e Ten memory channels numbered 0 through 9 available for storing operating frequency and mode of emission selected on a VFO addition there are two VFOs denoted VFO A and VFO B and a clarifier memory each of which hold both operating frequency and mode independently giving a total of 13 memories Selection and manipulation of the memories and VFOs is accomplished via the six keypad keys at the upper right corner of the front panel Note that the VFO M and keys have yellow marking in the notch on the keyfaces This is intended to serve as a caution that these keys cause data to be overwritten erased VFO Selection The operating vfo is indicated by VFO A or VFO B displayed to the left of the operating frequency Each vfo holds an independent frequency and mode of emission To select the alternate vfo press the VFO key VFO Memory Selection The MR VFO key at the upper right selects be tween memory and vfo operation Whenever this key is pressed the selected vfo or memory and its displayed frequency and indicated mode are stored except with temporary memory modes described below while operation shifts from vfo to a memory channe
14. by exceeding the current capabilities of the accessory DC jacks 8V and 13 5V may not be covered by the warranty policy 23 GND For best performance and safety connect this terminal to a good earth ground through the shortest path possible 3 2 MAN AUTO When this switch is set to the AUTO position the internal 4 bit keyer microprocessor is activated Keyer manipulator paddles must be connected to the KEY jack on the rear panel to operate the keyer When a straight key or bug is used set this switch to the MANual posi tion 3 SPEED This slide potentiometer sets the keying speed for the electronic keyer when the KEYER switch is set to AUTO and the keyer paddles are squeezed Slide this control to the right for faster keying INSTALLATION PRELIMINARY INSPECTION Upon opening the packing carton inspect the transceiver carefully for any signs of damage Check to ensure that all exposed controls and switches move freely and that the cabinet has no dents or scratches If you notice any dam age document it completely and contact the shipping company immediately Save the packing materials for possible future use BASE STATION INSTALLATION AC Power Supply The FT 757GXII requires a power source of 12 to 15 volts DC capable of up to 20 amperes on voice peaks For base station installations Yaesu offers a variety of AC power supplies all of which may be used with AC line voltages of
15. by the mode and the capability of the power supply in AM FM and afsk power may have to be restricted to avoid overheating the power supply Also there are certain precautions to be observed at all times when transmitting to avoid possible damage to the transceiver and to assure a clean signal Never transmit without having a dummy load or antenna tuned to the operating frequency connected to the transceiver or linear ampli fier if used If you have any doubt of the suitability of a particular antenna on a cer tain frequency check the SWR Standing Wave Ratio first as described below Avoid changing frequency during transmission First return to receive tune to the new transmit frequency and listen for at least a minute or two to make sure it is not already occupied or ask if the frequency is occupied and then listen for a response When using a light or medium duty power supply such as the FP 700 do not attempt to transmit FM AM or fsk at full output power Although the trans ceiver is capable of this some power supplies are not and they may rapidly overheat and be seriously damaged In any mode feel the supply occasionally and reduce power or stop transmitting for a while if it feels hot Never begin to transmit except into a dummy load without first listening for a few min utes to make sure the frequency is clear and then transmit your callsign This will avoid accidental interference to other stations S
16. by the operator s external per sonal computer Uni or bi directional serial data is passed via the CAT jack on the rear panel of the transceiver follows DATA RATE 4800 bits sec START BIT 1 DATA BITS 8 STOP BITS D PARITY none The chart at the bottom of this page shows the entire data sequence for one CAT command Data is transmitted from the computer to the SI Serial Input pin pin 3 of the CAT jack from left to right in the diagram So for example Parameter Parm 4 of the Command Block is sent first Note All data blocks sent to the 757 must be five bytes long The Instruction Code sent by the external com puter at the end of each 5 byte Command Block is the opcode that instructs the FT 757GXII what action is to be performed The Instruc tion Code Chart on the next page describes each valid Command If an invalid unlisted command is sent or if invalid parameters are recognized the transceiver the command Notice that most Instructions require only one or no arguments in the Parameter Bytes ever every Command Block sent to the FT 757GXII must always consist of five bytes The unused parameter bytes will be ignored will ignore How when such Instructions are executed so their value is irrelevant they need not be zeroed EXAMPLE to set 14 25000 MHz as the current operating frequency es 01 0 FREQ SET Instruction 00 50h 42h Olh
17. into the last used memory This will overwrite previous memory data and leave the vfo and memory the same This key is disabled when operating on memory MP VFO Press this key when operating on a memory to transfer its data into the last used vfo This will overwrite previous vfo data leav ing the vfo and memory the same After pres sing this key operation will be on the vfo 13 DLOCK This button disables the tuning knob to pre vent accidental frequency changes LOCK is shown on the display when active Press this button again to re enable tuning 14 Meter amp Display The meter shows relative signal strength in S units on the uppermost scale when receiving and either relative power output PO trans mitter automatic level control ALC or reflected power output SWR during transmis sion The METER button on the front panel and the FWD REV switch on the rear panel select the meter function for transmission To the right of the meter the ON AIR indicator glows red when transmitting and the GEN indi cator glows green when general coverage band stepping is selected via the H G button At the left side of the operating frequency the display tube includes the following indi cators LOCK tuning knob locked SPLT split frequency operation active CLAR clarifier active VFO A operating vfo or VFO B or operation is memory The digital frequency display indicates the operating
18. make certain that the t r switching requirements of your linear amplifier do not exceed these limits and that the linear switching voltage is DC and not DC or AC Yaesu offers the optional FRB 757 Relay Box for t r switching of linears that require negative or AC switching or higher voltage or current switching The FRB 757 in stalls between the relay jack on the amplifier the PTT jack on the transceiver and is 7570 1 SXI capable of switching up to 250V DC at up to 2 5A If using the FC 757AT antenna tuner or a QSK linear amplifier such as the Yaesu FL 7000 or Alpha 78 connect pin 8 INH transmitter inhi bit of the BAND DATA jack to the exciter control line from the and set the LINEAR switch to the ON depressed position the transmitter activation circuitry linear to allow in the linear to control the transceiver If using a non QSK linear amplifier such as the Yaesu FL 2100B or most Henry or Heathkit linears make sure that the LINEAR switch on the transceiver is OFF out oc sv p ext se ac wov FT 757GX 1 5 FP 757HD vue 757 5 m 757 0 FT 757GX I SXI 700 FP 757HD LINEAR NIS ET 757GXI CONNECTION CABLE 790296 CONNECTION CABLE A
19. scan the desired range and then turn the SQL control until the receiver is quiet Of course this will only work if the expected signal is strong enough to overcome the squelch threshold Otherwise when not scanning the SQL control should be set fully counterclockwise Note Whenever using the squelch feature make sure to set up the RF AMP ATT and RF gain as described previously before adjusting the SQL control as the squelch threshold is affected by these front end settings CW Reception In addition to the interference and noise reducing controls described for SSB the FT 757GXII CW N narrow mode provides 600 Hz IF filter to enhance reception Use the CW W wide mode to tune in the desired signal for an 700 Hz pitch and then press the MODE button to select CW N Keep the AGC F switch in the fast depressed position for CW reception and reduce the RF gain as much as possible to suppress back ground noise The CW W mode provides the same IF bandwidth as for SSB but with a special internal audio filter to reduce the audio bandwidth allowing you to hear signals up to about 1 kHz away while tuning around the band Noise and inter ference are greater than for CW N but the wider bandwidth makes tuning easier The NOTCH filter is useful in both wide and narrow CW modes to suppress a stronger nearby CW signal in order to hear a weaker one Just turn the NOTCH control to set the notch on the undesired sig
20. set by Parameter of the Return Delay command to allow enough time for the computer program to get set to receive the Status data The transceiver then returns either one byte if Parameter is set to 1 in the Read Status command for the S meter indi cation or 75 bytes for complete status information on the vfos and all memories In the latter case each of the 75 bytes is sep arated by the delay set by the last time the Return Delay command was sent Note that 75 bytes are always returned after the Return Delay command as well as after the Read Stat us command with Parameter 1 0 The Status Update Chart and accompanying tables show the format of the 75 bytes re turned after the Return Delay command or when the Read Status command is sent with a 0 para meter notice that some flags are carried bit fields in the first status byte The CAT jack also provides access to the PTT Push To Talk line at pin 4 to allow keying the transmitter This pin has 8V DC on it when open circuit during reception and ac tivates the transmitter when grounded sour cing 8 mA INSTRUCTION CODE CHART NOTE Commands are sent in the REVERSE of the order shown in this Chart Instruction Code Parameters Name Hex Remarks MSD 1 2 3 4 LSD SPLIT 01h 1 1_ 00 OFF or 01 ON 2 pi xx xx p 00 09 Channel No M 03
21. so that extran eous sounds do not interfere with your trans mitted signal Select LSB or USB mode and set the PROC switch off The PTT jack on the rear panel may be used for external transmit receive control or press the VOX button to allow automatic transmit receive switching either full or semi break in may be used Manual transmit receive control is also possible with the MOX button Note that the displayed frequency is the sup pressed carrier frequency so your actual MARK and SPACE frequencies will be displaced from the display by the audio frequencies of the tones Use the MIC gain control to adjust power out put while transmitting for full power set the MIC gain so that the meter showing ALC deflects slightly Reduce power output by turning the MIC gain counterclockwise from full power and observing power output on the PO meter after calibrating as described pre viously or on an external wattmeter As mentioned previously the FT 757GXII is capable of full power AFSK transmission for limited periods when used with a heavy duty power supply Restrict transmissions to 30 minutes with the FP 757HD If using the FP 700 restrict RTTY or packet power output to 50 watts maximum However if the air temperature is high or at high altitudes cooling efficiency is decreased and so power output should be reduced accordingly Also it is a good prac tice to back off on the power whenever making a long transmission
22. to the frequency and mode of emission to be stored 2 While receiving press MR VFO to switch from vfo to memories 3 Press the DWN UP keys if necessary to select an unused memory channel default data is 7 000 MHz LSB in all channels 4 Press MR VFO again to return to the vfo 5 Press lower center to write the data from the vfo to the memory Note that the VFO MR key overwrites erases the previous memory contents Steps 2 3 and 4 are required only to select the memory channel that is to be written If you already know that the last selected memory is free to accept new data these steps can be skipped YES 1 Connect the voltmeter to jack J1023 on the RF Unit Select a CW mode and note the voltmeter reading with the transmitter keyed 2 3 Return to receive select the AM mode key the transmitter and with no modulation adjust the AM CAR potentiometer for exactly one half of the voltage that was measured in the CW mode ad S Jioza Unless using a heavy duty power supply keep transmissions short and stop transmitting if the power supply becomes hot RTTY HF Packet amp SSTV Transmission Transmission of narrowband FSK Fl RTTY SSTV and Bell 103 HF packet requires input of equal level audio tones AFSK at the 600 ohm PATCH jack on the rear panel Remove the microphone from the MIC jack so that extran eous sounds do not interfere with your trans
23. type to wide woodpecker blanking pulse widths Full break in QSK CW operation is provided with Yaesu s custom designed elec tronic keyer built in as a standard feature New high voltage solid state transmit receive switching circuitry is provided for direct t r control of a wide variety of QSK and non QSK linear amplifiers SSB and AM signal punch be increased by the AF speech processor which combines clipping and compression circuitry to optimize average speech power with minimum distortion Careful filtering before modulation assures clean output with a substantial increase in average power The diecast top half of the FT 757GXII serves as the heatsink for the final power amplifier and forced air cooling through the chassis allows full power FM and AFSK operation when used with a heavy duty power supply Optional accessories include your choice of the MD 1B8 Desktop Scanning Microphone or the 188 Handy Scanning Microphone and the microprocessor controlled FC 757AT 100 watt Automatic Antenna Tuner or FL 7000 500 watt Automatic Solid State QSK Linear Amplifier each of which automatically selects and tunes up to five antennas when used with the FAS 1 4R Remote Antenna Selector Power supplies for the FT 757GXII include the FP 757HD Heavy Duty Series Regulator Power Supply with forced air cooling and automatic thermal fan control or the light duty FP 700 standard supply ideal when the transceiver is used as an exciter
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25. 11 SCAN MODE Pushbutton Switch Press this 2 position switch to select scan ning facilities While depressed the func tions of the DWN amp UP keys and the VFO and Memory keys are altered from the basic functions described in this section to select and control various scanning functions as described in the Operation section 12 VFO and Memory Keys These six keys transfer frequency and mode data between the vfos and memories A beep As they function as receive changes while transmit Two keys have yellow markings to indi cate that data will be overwritten when they are pressed Some of these keys also take on special functions when the SCAN MODE switch is depressed These are described later sounds when one is pressed during transmit as well use care to avoid accidental ting VFO A B This key exchanges the contents of the two vfos called A and B SPLIT Press this key to activate split frequency operation between the two vfos and press it again to cancel split operation MR VFO This key switches operation between the last used vfo and the last used memory The frequency and mode data in the vfo and mem ory are unaffected The display indicates which vfo or memory is currently selected VFORAM This key exchanges the frequency and mode contents of the last used vfo and the last used memory Press this key when operating on a to store the frequency and mode data from that vfo
26. 2 conductor mini phone jack provides amplified receiver output to drive an external 4 to 16 ohm loudspeaker 19 KEY This 4 inch 3 conductor phone jack accepts keyer paddles for the internal electronic keyer or a straight CW key when the internal keyer is switched off Wiring connections are shown on page 17 Open circuit voltage is 5V DC and closed circuit current is 0 5 mA CAUTION None of the three KEY jack contacts are connected to chassis ground DO NOT con nect the outer contact to chassis ground 20 RF OUT This phono jack provides low level RF output from an early stage of the transmitter for exciting a transverter Power level is approximately 6dBm 0 1 Vrms at 50 ohms 1 BREAK IN This slide switch selects semi or full break in CW operation in conjunction with the MOX and VOX switches on the front panel as indi cated in the following chart BREAK IN VOX MOX Resulting function SEMI OFF OFF SEMI OFF ON SEMI ON OFF FULL OFF OFF FULL OFF ON FULL ON OFF Sidetone only no tx Tx when keydown no rx Semi break in CW Full break in CW Continuous carrier tx Semi break in CW 21 8V This phono jack provides 8V DC at up to 100mA for low power accessories The center contact is positive 22 13 5V This phono jack provides 13 5V DC at up to 500 mA for powering accessories The center tact is positive Note Repairs to damage caused
27. BLE C 79101337 0 5 o arr OFF emn 7576 FL 7000 CONNECTION CABLE 179009807 4 LINEAR SWITCH Il orr LINEAR FP 757HD s hehe or e FRB8 757 i LINEAR SWITCH QSK LINEAR FP 757HD y OPTIONAL CABLE TSIOI95A Note Relay control voltage from the linear amplifier must be less than 50 V and relay coil current less than 300 i cms ad QSK Linear Amplifier Connection Cable Option IB 9101295 GNDlshield 21 i TX GND White Be 5 s INH Red 151555 4 7 xil PIN 25 F2591000 No 1xx E CIRCUIT DIAGRAM reloge STe e 2 CERS mms 2 LINEAR 757 5 CONNECTION 0 25 79101292 S FT 757GXI SXI FAS I 4R 757 CONNECTION CABLE A TSIOOIGOA Main Knob Torque Adjustment Screw BOTTOM MICROPHONES mJ Co ete deal own Plug assembly MH 188 t wure sevect 590 50 SS D vice GIO z E ul i own rast
28. C Power Cord w o fuse T9014900 Fuses 2 supplied 7576 20 00000009 FT 757SXIl 6 00000012 3 pin Phone plug 5 3603 P0090008 RCA phono plugs STP 58 2 pcs P0090018 FIF 65A SP 767P FIF 232C Options Model MD 1B8 MH 1B8 FRB 757 MMB 20 FIF 65A FIF 232C FP 757HD FP 700 FC 757AT FL 7000 FAS 1 4R SP 767 SP 767P SP 55 75 Part No Desktop Scanning Microphone D1000039 Hand Scanning Microphone D1000040 Relay Control Box 103000280 Mobile Mounting Bracket D6000032 External Computer Interfaces for Apple II for RS 232C Heavy Duty Power Supply Standard Duty Power Supply Automatic Antenna Tuner 100W 500W QSK Automatic Linear Amplifier Remote Antenna Selector 1 2kW for use with FC 757AT or FL 7000 Base Station Loudspeaker Base Loudspeaker w Phone Patch Mobile Loudspeaker Connection Cable to FIF 232C FL 7000 FC 757AT FRONT PANEL aene 1 POWER This pushbutton switch turns the transceiver on and off Frequency and mode data stored in the memories and vfos is not affected by this switch or by whether power is connected to the transceiver since this data is retained by an internal lithium battery while the backup system is activated 2 This 8 pin connector accepts the plug of the MD 1B8 Desktop Mic or MH 1B8 Hand Mic Scanning control lines from these microphones allow pushbutton fast and slow tun
29. F N INST 5 REM Instruction Set vfo 1 IF INS Ss e e REM Instruction Set vfo A B P1 vfo B IF GOTO 800 REM Get Update Status GOSUB 1000 GOTO 100 REM Send 5 bytes to xcvr and loop back to menu REM Select data to read from Transceiver INPUT Hit 0 for all Stats or 1 for S meter TYPE REM Determine type of data to read IF TYPE 0 THEN 900 REM Jump for S meter data a E 830 REM Send Return Delay Command returns 75 byte Status Update 840 INST 14 P1 100 GOSUB 1000 850 REM Read 75 bytes as they come back from Transceiver REM Set resp delay to 100ms get Status Update dine 860 FOR I 0 TO 75 REM Set Retry counter 870 GOSUB 2000 REM Check serial port input status 880 PRINT Status Byte 4 PEEK IOPORT REM Print status byte read 890 NEXT I GOTO 100 REM Read another byte return to menu if done 900 REM Send Read Status Command and read i byte S meter data REM Inst Read Status P1 S meter Send it 910 INST 16 P1 1 GOSUB 1000 920 60508 2000 930 PRINT Signal Strength is PEEK IOPORT 940 GOTO 100 1000 REM Send 5 bytes to Transceiver 1010 POKE IOPORT P4 POKE IOPORT P3 POKE IOPORT P2 POKE TOPORT P1 1020 RETURN 2000 REM Check serial port input status 2010 IOSTAT PEEK CMDPORT 2020 RXRDY INT IOSTAT 2
30. F speech processor to increase average speech power during SSB transmission according to the level set by the COMP LEVEL control on the rear panel NB T activates the noise blanker for SSB CW and AM reception The NB control at the lower right corner can then be used to set the blanking pulse width activates fast decay time for SSB CW and AM reception to facilitate scanning and tuning or listening to very weak sig nals When not depressed slow agc decay is provided for more comfortable reception of strong signals 17 MOX and VOX Pushbutton Switches The transmitter can be manually switched on and off by the MOX switch This is useful for SWR measurement and antenna tuning The VOX switch activates voice actuated transmit receive switching and semi break in CW keying In SSB AM amp FM modes when this switch is in the depressed position the transmitter will be activated just by speaking into the microphone When finished speaking or releasing the CW key in CW mode the recei ver will be automatically reactivated after a short delay as set by the DELAY control on the rear panel REAR PANEL CONTROLS amp CONNECTORS X DC 13 5V This 4 pin connector accepts 12 to 15V DC at 19 amperes transmit to power the transcei ver Pinout is shown on page 13 CAUTION AC voltage or DC outside of this range may damage the transceiver 2 BAND DATA This 8 pin molex connector provides parallel TTL l
31. Transmission The FT 757GXII offers both semi and full break in QSK operation for both simplex and split frequency operation However QSK tion must not be attempted while using linear amplifier not specifically designed for it or damage to the amplifier or transceiver may result See page 14 The FT 757GXII includes an internal electronic keyer which can be used by connecting keyer paddles to the KEY jack You can also use a straight key or an external electronic keyer in which cases the internal keyer must be switched off top panel KEYER switch to MAN Be careful not to short the outer contact of the KEY jack to chassis ground Set up the following front panel controls VOX switch ON depressed METER 2 2 DRIVE control clockwise max MODE switch select CW W or CW N Also on the top panel set the KEYER switch to MAN initially Close the key to activate the transmitter and adjust the DRIVE control so that the ALC meter just starts to deflect This setting provides full power output after making contact with another station reduce power with the DRIVE control if you can with out loosing contact You should be able to hear the sidetone from the loudspeaker or headphones when you close the key The sidetone control inside the hole near the rear of the bottom cover can be adjusted for comfortable sidetone volume E set the internal keyer spe
32. WR Checking amp Measuring Before transmitting the SWR of the antenna system should be checked at the operating fre quency to ensure that the proper impedance is being presented to the transmitter The trans mitter includes protection circuits that will automatically reduce the output power if SWR is high For example with an SWR of 3 1 only about 7596 of full power is available If using the FC 757AT Automatic Antenna Tuner or FL 7000 Linear Amplifier SWR is calculated and displayed automatically and the following procedures are not necessary this case keep the METER switch on the FT 757GXII in the ALC undepressed position See the Tuner or Amplifier manual for complete details Keying the Transmitter Use the MOX button to activate the transmitter during the following procedures Before begin ning set the BREAK IN switch on the top panel to FULL and the VOX button on the front panel to off out To transmit set the MOX button to the depressed position and then press it again to receive undepressed position SWR Checking This procedure checks the approximate SWR using just a few watts to avoid interference and strain on the equipment when SWR is un known such as on a new antenna 1 On the rear panel set the FWD REV slide switch to the FWD position and turn the FWD SET control fully clockwise as viewed from the rear 2 Make sure the DRIVE control is set fully counterclockwise Set the METER sw
33. ck Use 50 ohm coaxial cable with a proper plug to connect the transceiver to the antenna or load and if SWR is too high to permit the desired performance connect an antenna tuner such as the automatic FC 757AT or the FC 700 between the transceiver and the antenna See page 22 for SWR measurement with the FT 75 and pages 14 16 for interconnection information 22 MOBILE INSTALLATION Negative Ground vehicles only The DC power cable for mobile installation is supplied with the transceiver Please review the NOTICE on page 11 before making power con nections The DC cable should be connected directly to the vehicle battery rather than to the ignition or accessory circuitry Route the cable as far away from ignition cables as possible and then cut off any extra cable in order to minimize voltage drop losses 1 Do not connect the cable to the transcei ver until after the proper connections are made to the battery the RED cable lead to the POSITIVE battery terminal and BLACK lead to the NEGATIVE terminal Make sure the battery terminal connec tions are tight and remember to check them periodically for signs of loosening or corrosion 2 Measure the voltage across the battery terminals with the engine running fast enough to show a charge If above 15 volts the automobile voltage regulator must be adjusted to reduce the charging voltage before proceeding BLACK BLACK 1 BATTERY 3 Make sure the
34. ech Processor After setting the MIC gain as above press the PROC switch to activate the processor The average ALC indication on the meter will in crease but if the peak indication deflects past the ALC zone reduce the MIC gain age LEVEL control on the rear panel adjusts the level of speech processor compres sion and is carefully set for optimum perfor mance at the factory However using different microphones or variations in voice pitch may make it desirable to readjust this control This can be done by monitoring the transmitted signal on an oscilloscope or external receiver and adjusting the COMP LEVEL control to the point just below that at which distortion appears on the signal If set beyond this point average power will still be increased but distortion will cause signal intelligibil ity to be decreased VOX Voice actuated Transmit Switching In any of the voice modes you can use the VOX system to automatically activate the transmit ter when you speak into the microphone Press the VOX switch to activate VOX and then adjust the VOX control on the rear panel so that the transmitter activates when you speak without pressing the PTT switch on the micro phone When you stop talking the transceiver should return to receive after a slight delay The DELAY adjustment on the rear panel sets the hang time for VOX switching from transmit to receive If the audio from the receiver triggers the
35. ed trimmer potentiometer sets the ratio of transmitted carrier to modulation for AM transmission Adjustment is described in the Operation section 9 MARKER Set this pushbutton switch to the depressed position to activate the 25kHz marker signal generator which produces a carrier at multi ples of 25kHz across the frequency range of the receiver When the calibration signal is not needed this switch should be off out to avoid interference with normal reception This switch also functions in conjunction with the LINEAR switch to disable the memory backup as described later 10 CAT This 6 pin mini DIN jack provides access to the serial data lines from the microcomputer and A D converter for control of the trans ceiver from an external computer See the CAT section of this manual for details 11 PTT Jack This phono jack provides access to the PTT line for external receive transmit control by a footswitch or other device Connecting the inner contact to the outer contact chassis ground activates the transmitter Maximum open circuit voltage present is 13 5V minimum closed circuit current is 0 3 mA 12 ANT Coaxial Jack This type M SO 239 jack is for the antenna system antenna tuner or linear amplifier input Impedance requirement is 50 ohms un balanced Use only a properly mating type M PL 259 plug and 50 or 52 ohm coaxial cable 13 PATCH AFSK This phono jack accepts transmitter input from
36. ed or to tice sending CW set the VOX switch off out and the BREAK IN switch to SEMI Also set the KEYER switch to AUTO if using keyer paddles Now closing the key will generate the side tone but no signal will be transmitted Ad just the KEYER control for the desired speed For QSK transmission set the VOX switch OFF out and BREAK IN to FULL For semi break in operation as required with some linear amplifiers set the VOX switch ON depressed and BREAK IN to SEMI The DELAY control on the rear panel adjusts the hang time between key up and receiver enable FM Transmission For FM transmission just select the FM mode and close the PTT switch to transmit The MIC gain control is disabled for FM as the gain of the microphone amplifier is preset inter nally for 5 kHz deviation and should require no further adjustment RF power output is adjusted by the DRIVE control For full power output using the FP 757HD power supply adjust the DRIVE so that the meter set for ALC just deflects slightly When contact is established reduce the DRIVE E CAUTION When the FT 757GXII is used with the FP 757HD power supply full power FM AFSK RTTY transmissions must be limited to 30 minutes maximum When the FP 700 or other light duty supply is used transmitter power in the above modes must be limited to 50 watts at all times to avoid overheating and subsequent damage to the supply Regardless of
37. elect the CW W mode set the METER switch to PO in and set the DRIVE control fully clockwise maximum On the rear panel set the FWD REV switch to FWD 2 Check that the frequency is clear then press the MOX button and carefully adjust the FWD SET control on the rear panel so that the meter indicates 100W on the PO center scale Return the MOX button to off receive The accuracy of this calibration is very rough as the actual full power output depends on the band of operation and the antenna SWR If you have an accurate wattmeter and 50 ohm dummy load you can use these in the above procedure Set the DRIVE control for 100W out put before adjusting the FWD SET control SSB Transmission With a microphone connected to the MIC jack on the front panel ensure the following controls are preset as indicated METER selector ALC MIC gain control 12 o clock inner knob right of the MIC jack PROC switch OFF out IVOX Switeh 225 aes 777 lout select LSB USB Tune to a valid transmitting frequency in the amateur bands To activate the transmitter close the PTT switch on the microphone and watching the ALC indication blue scale on the meter adjust the MIC gain control so that the meter de flects within the ALC zone heavy blue line on the scale on voice peaks This will result in full power output reduce the MIC gain to reduce power Spe
38. evel bandswitching signals for the FC 75 Antenna Tuner and also QSK control signals for the FL 7000 Linear Amplifier See the CAUTION notice on page 14 if you wish to use another model linear amplifier aire K 16 15 3 LINEAR This pushbutton switch activates external con of t r switching by the FC 757AT FL 7000 or other linear amplifier designed for QSK operation If not using one of these accesso ries this switch must be in the undepressed position for transmission This switch also functions together with the MARKER switch to disable the memory backup as described in the Operation section 4 DELAY This control sets the delay between the time that speech stops or the CW key is opened and the time that the receiver is reactivated when the VOX system is activated by the switch on the front panel 5 ANTI TRIP This control sets the amount of negative receiver audio feedback applied to the VOX amplifier during VOX operation The level should be set so that speaker audio does not key the transmitter 6 VOX GAIN This control sets the gain of the VOX ampli fier for VOX operation The optimum setting depends on the microphone used and the voice characteristics of the operator 7 COMP LEVEL This control sets the compression level of the audio speech compressor during SSB transmis sion with the processor PROC switch on See the Operation section for adjustment 8 AM CAR This recess
39. frequency with 100 Hz resolution When operating on a memory the memory channel number 0 thru 9 is displayed with CH to the right of the frequency 15 CLAR Press this button while receiving on a vfo to activate clarifier operation The tuning knob and DWN amp UP keys can then be used to tune the receiver without affecting the transmit fre quency Press this button again to cancel the change in receiver frequency and return to where you were The clarifier is disabled when receiving on a memory 16 Pushbutton Switches Each of these switches has two positions when depressed the labelled function is on when undepressed the labelled function is off except for the METER switch described next METER selects either ALC or power output functions of the meter during transmission Power output functions forward or reverse are in turn selected by the FWD REV switch on the rear panel ALC is indicated when this switch is in the depressed position and power output when it is undepressed RF AMP activates the rf amplifier in the receiver front end when depressed for max imum receiver gain In the undepressed posi tion the RF amplifier is bypassed for increased immunity to overload from strong signals on other frequencies ATT places a 20dB attenuator in the receiver front end circuit to reduce sensitivity and avoid overload of the rf amplifier and mixer when listening to very strong signals PROC activates the A
40. h pi xx xx xx 00 09 Channel No D LOCK 04h pi xk p 00 OFF or 01 ON VFO A B 05h p1 xx xx 00 or 01 B M VFO 06h pi Era aeo sexe pi 00 09 Channel No BAND UP 07h xx Step up Band BAND DWN 08h xx Step down one Band CLARIFIER 09h pi 1 00 OFF or 01 ON FREQ SET p1 p2 p3 Set see EXMPL SWAP 5 MODESEL xx xx xx pl value 00 LSB 01 USB 02 CWW 03 CWN 04 AM 05 FM HGSEL ODh pi p1 00 GEN or 01 HAM RETURN DELAY pi xx p 00 to FFh ms delay READ STATUS 10h pli xx xx xx pl 00 or 01 Meter only any value byte will not affect command function Band steps determined by current Ham Gen selection Ham bands or 0 5 MHz Delay between response bytes from transceiver after receipt of RETURN DELAY or READ STATUS command This command only functions when operating on a vfo test Status Update Byte 1 Bit 3 MR vfo flag Parameters must be in BCD format e STATUS UPDATE CHART format of data returned by 757GXII after RETURN DELAY command or READ STATUS command with 0 parm Byte Contents Ref No Table 1 Status Flags 1 2 SCAN MODE 00 OFF 80h ON 3 __ not used
41. he micro phone FAST button This allows quick searching for activity with the FAST button pressed and then easy fine tuning when the FAST button is released To jump up or down one coarse step press the microphone FAST and either UP or DOWN key together NOTE Under certain conditions the tuning knob is deactivated These are when the D LOCK dial lock MR memory recall or SCAN MODE functions are active When the dial is locked or a memory has been recalled LOCK and appear respectively on the display Press the D LOCK button to deactivate the dial lock or press the MR VFO button to return control to a vfo If neither of the above mentioned conditions is displayed reset the SCAN MODE button to the undepressed position to turn off the scanner Memory Backup Before leaving the factory the memory backup system is turned off Activate the backup by setting the MARKER and LINEAR switches on the rear panel to their undepressed off posi tions If you are using a QSK linear the LINEAR switch must be kept in the depressed position in which case only the MARKER switch needs to be set to off If you want to clear all memories or if you plan to store the transceiver for a long time without power connected disable the backup system by pressing both the LINEAR and MARKER switches to ON while the transceiver is off Ens SSB Reception Interference Reduction Except for the vfo and memory control ke
42. hen VFO A B while operating on a vfo Press FAST to select high speed scanning Scanning will pause on a signal and resume if the signal drops out or manually by turning the SQL clockwise Pressing VFO while paused moves the frequency one step To manually stop scanning and set the selected vfo to the displayed frequency press VFO A B or the PTT switch momentarily To cancel scan ning altogether return SCAN MODE to the out off position Programmable Memory Scanning PMS The PMS feature allows you to scan all frequencies between those stored in any two adjacent memory channels The starting frequency and mode of the scanner are determined by the selected memory gt channel Slow and fast x10 rates selectable as for vfo scanning Which ever vfo was last selected prior to activating PMS will be changed by PMS scanning To use programmable memory scanning 1 Store the lower and upper scanning limits in adjacent memories and select the one you want to start at 2 Preset the SQL control to the point where background noise is just silen ced 3 Press SCAN MODE on and then press the DWN key to scan to the next lower Press while receiving on a vfo to switch to the alternate vfo Also when Scan Mode on starts scanning between v os and steps stores scanned frequencies VFO A B Press while receiving to ex change vfo or memory contents with those of las
43. if you are listening for weak signals IF Shift amp Notch Filter If you experience interference from stations on nearby frequencies after tuning in a station and setting the rf controls as just described rotate the SHIFT control to sup press the interference Usually interference on one side of the desired signal is worse than on the other and by shifting the pass band toward the clearer side reception of the desired signal can be improved Notice however that the passband of the desired signal is also shifted so turning the SHIFT control too far may cut off too much of the low or high audio components and make the signal unintelligible The IF notch filter is primarily useful for suppressing heterodynes in CW and ECSS recep tion as described later However it is also a powerful tool for suppressing other types of interference such as computer generated buzzing noise in the SSB mode After tuning in the desired signal and setting the SHIFT for optimum copy if you are receiving a buz zing type noise turn the NOTCH on out of the click stop and watch the S meter while tuning the notch control for minimum deflec tion on the noise when the other station isn t talking Of course this same technique can be used to suppress interfering CW signals or carrier heterodynes during SSB reception mm SSB Reception Interference Reduction Except for the vfo and memory control keys the remaining controls for the receive
44. ing from the microphone duplicating the functions of the tuning knob and FAST button See page 17 for pinout 3 PHONES Monaural or stereo headphones with 4 16 ohms impedance may be connected to this jack Stereo headphones with a 3 conductor plug will reproduce the audio in both ears as with mon aural headphones with a 2 conductor plug Inserting a plug into this jack disables the internal or external loudspeaker CONTROLS 4 MIC DRIVE The inner control adjusts the gain of the transmit audio amplifier used during SSB and AM transmission for FM gain is preset internally This control adjusts output power in SSB modes when the speech pro cessor is off and modulation level in the AM mode It is disabled when the processor is on and during FM and CW transmission The outer DRIVE control adjusts the carrier power output level for CW AM and FM transmis sion This control is disabled during SSB transmission 5 AF RF The inner AF control adjusts receiver volume The outer RF control adjusts the gain of the receiver RF and IF amplifiers via the age line This control is normally set fully clockwise for peak receiver sensitivity When it is set counterclockwise from maximum the S meter minimum deflection point will be moved up the scale and weaker signals or noise although S meter deflec tion for stronger signals will remain the same This control also affects the squelch threshold a
45. itch to the PO depressed position and select the CW W mode 3 Tune the vfo to a clear frequency and listen for a minute to make sure its clear before proceeding Press the MOX button the red ON AIR indicator will light and very gradually advance the DRIVE control while watching the meter for any deflection Now adjust the DRIVE control so that the meter de flects exactly to the SET marker white line cutting the red bar at the right side of the SWR meter scale 4 Set the MOX switch back off out Reach back around to the rear panel and move the FWD REV slide switch to the REV posi tion Now press the MOX switch again to 5 key the transmitter and note the SWR approximation on the bottom scale of the meter Press the MOX switch again to return to receive If the SWR indication was above 3 the antenna system is too far from resonance to be used at the test frequency without substantially degraded performance not recommended SWR em indication close to 3 indicates poor antenna match at this frequency but an antenna tuner such as the FC 757AT may be used to match the antenna better reducing the SWR Of course this will not change the radiating qualities of the antenna itself and will require retun ing whenever the transmitting frequency is changed so it is better to correct the anten na or feedline mismatch first if possible SWR indications of 1 5 or less indicates a matched antenna f
46. l or vice versa The vfo or memory channel recalled is always the one that was last used When a memory channel is sel ected MR appears to the left of the displayed frequency and CH appears to the right with the channel number beneath it Split Frequency Operation The two vfos and the SPLIT key can be used for Split frequency operation as follows 1 Press VFO A B if necessary to select VFO B displayed at the left 2 Tune to the desired transmit frequency and mode 3 Press VFO A B to select VFO A and tune to the desired receive frequency amp mode 4 Press SPLIT Now receiving is VFO A but when the PTT switch or key is closed transmission is on VFO B To reverse transmit and receive frequencies for example to listen on the transmit frequency just press VFO A B An alternative method to operate split is to use one vfo and the clarifier mentioned previously in the SSB Transmission section Tune the vfo to the transmit frequency then press CLAR and tune to the receive frequency and other mode if re quired To listen on the transmit frequency press CLAR again and then once more to return to the receive frequency which is stored in a clarifier memory Note however that the clarifier memory is lost if the tuning knob moves while checking the transmit frequency Memory Storage This procedure allows storage of the vfo mode and frequency into a memory channel 1 Set the VFO
47. n other frequencies After selecting the proper ATT and RF AMP settings if background noise still causes the S meter to deflect note the level and then rotate the RF gain control counterclockwise from maximum until the S meter deflection just begins to increase slightly above the noise level This will reduce the background noise when you listen to signals In general the attenuator may often be needed on frequencies below 10 MHz and when you are using a large antenna or your station is in a noisy environment city The RF AMP should rarely be needed below 10 MHz unless you have a small antenna or your station is in a quiet environment Do not activate the attenuator and RF AMP at the same time instead switch both off The settings described up to this point are best for tuning and receiving weak signals under most conditions In most cases once you have tuned in a station you will want to set the AGC F off out slow agc for most comfor table listening If you are working a strong station consistently above S 9 turn on the the attenuator if it isn t already on or turn off the RF AMP if it s on and decrease the RF gain so that his signal just moves the S meter above its raised resting position You should notice a reduction in background noise and more comfortable copy When retuning the vfo set the AGC F back on fast and return the RF and ATT to their previous settings if you are listening for weak signal
48. nal This should be done both by ear and by observing the S meter for a dip Hint when you make contact with another sta tion on CW press the D LOCK button to avoid accidental frequency change Spp AM Reception The FT 757GXII includes a 6 kHz filter for good fidelity during reception of medium and shortwave AM broadcasts The NOTCH filter is useful for eliminating carrier heterodynes whistles produced when two stations are transmitting near the same frequency but when not needed it should be switched off for best fidelity The SHIFT control is less effective than in the narrower modes but it is useful for eliminating high pitch hiss and hetero dynes from stations more than 3 kHz away When interference or noise is severe ECSS Exalted Carrier Selectable Sidedband recep tion may be preferable for receiving AM signais This special technique allows you to select either the upper or lower sideband of an AM signal eliminating interference that may be present on the other sideband due to a nearby signal It also provides greater selec tivity resulting in greater sensitivity and SHIFT control effectiveness but does not provide as much fidelity for strong signals as the AM mode To use the ECSS technique first tune in the station precisely shortwave broadcasters gen erally transmit on precise multiples of 5 kHz using the AM mode and then select either USB or LSB whichever gives best reception Now carefully fine
49. nd so should be set before the SOL squelch will be suppressed control 6 Tuning Knob and FAST button This knob tunes the transceiver at a rate determined by the operating mode and selected by the FAST button Tuning Rates in kHz step MODE FAST ON FAST OFF SSB CW 1 kHz 10 Hz AM 10 kHz 1 kHz FM 10 kHz 2 5 kHz This knob is disabled when the LOCK button is pressed during transmissi n or when operating on a memory A torque adjustment screw for the tuning knob is accessible through the hole on the bottom of the transceiver just beneath the knob see page 16 7 NOTCH SHIFT The inner NOTCH control activates the IF notch filter when turned clockwise out of the click stop and tunes the notch across the IF pass band its setting is independent of the oper ating frequency and IF Shift setting Set this control into the click stop off when the notch filter is not needed The notch filter is disabled in the FM mode The outer SHIFT control sets the position of the receiver IF passband relative to the rece iving frequency in SSB CW and AM modes to suppress interference on nearby channels At the 12 o clock position the IF is centered on the displayed receiving frequen cy turn this control counterclockwise to lower the IF passband or clockwise to raise the passband When no interference is present set this control to the 12 o clock position 8 SQL NB Squelch Noise Bla
50. nker The inner squelch control is used to set the threshold level of incoming signals or noise at which receiver audio is muted This threshold point also serves as the scan stop setting when scanning Clockwise rotation increases the threshold level causing the receiver not to respond to background noise or weaker signals The outer noise blanker control adjusts the decay time of the noise blanker agc which determines the width of the blanking pulse when the noise blanker is activated during SSB and CW reception and AM when the noise pulses are stronger than the received carrier 9 BAND CH DWN amp UP keys and H G button During reception with a vfo the two large DWN and UP keys are used to change frequency bands and for 500 kHz steps The H G Ham General coverage band step selector button determines whether the DWN amp UP keys step through the amateur bands only or in 500 kHz general coverage steps A beep sounds when any of these are pressed See the Operation sec tion of this manual for details When receiving on a memory the H G button is disabled and the DWN amp UP keys step through the memories Also when the SCAN MODE switch is pressed the DWN amp UP keys activate and deactivate PMS scanning between memories 10 MODE Select Button and Indicators Press this button to select the operating mode while receiving a beep will sound The sel ected mode is indicated by one of the six LED indicators
51. ntact but overwrites all data in the vfo and leaves operation on the vfo SCANNING When the squelch control is adjusted to silence the receiver either the memories or a preselected frequency segment may be scanned automatically Signals that are strong enough to open the squelch will halt the scanner Note that the RF AMP and ATT switches and the RF gain control must be set for the desired sensitivity before adjusting the SQL control as these will affect the squelch sensitivity The SCAN MODE switch activates the scanning modes during which the VFO A B and MR VFO keys adopt alternate functions as explained below Memory Channel Scanning To scan the 10 memory channels 1 Preset the SQL control to the point where background noise is just silen ced 2 Press MR VFO to recall the memories 3 Press SCAN MODE and MR VFO again to start the scanner Scanning will pause on any channel having a signal strong enough to open the squelch and will resume again if the signal drops out While paused if you press MR VFO a double beep will sound and operation will shift to the next higher numbered channel To stop the scanner manually press MR VFO or the PTT switch momentarily Return the SCAN MODE switch to the off out position to return the vfo memory keys to their standard functions Scanning Between Vfos If you set up the vfos as scanning limits you can scan all frequencies in between by pressing SCAN MODE and t
52. od of overload from strong signals on other frequencies After selecting the proper ATT and RF AMP settings if background noise still causes the S meter to deflect note the level and then rotate the RF gain control counterclockwise from maximum until the S meter deflection just begins to increase slightly above the noise level This will reduce the background noise when you listen to signals In general the attenuator may often be needed on frequencies below 10 MHz and when you are using a large antenna or your station is in a noisy environment city The RF AMP should rarely be needed below 10 MHz unless you have a small antenna or your station is in a quiet environment Do not activate the attenuator and RF AMP at the same time instead switch both off The settings described up to this point are best for tuning and receiving weak signals under most conditions In most cases once you have tuned in a station you will want to set the AGC F off out slow agc for most comfor table listening If you are working a strong station consistently above S 9 turn on the the attenuator if it isn t already on or turn off the RF AMP if it s on and decrease the RF gain so that his signal just moves the 5 meter above its raised resting position You should notice a reduction in background noise and more comfortable copy When retuning the vfo set the AGC F back on fast and return the RF and ATT to their previous settings
53. or use at the test frequency SWR Measuring Use full power to measure SWR more precisely 1 Set the FWD SET control on the rear panel to midrange and set the FWD REV switch to FWD Use the CW W mode and MOX button as above for the following steps 2 Set the METER switch to ALC out 3 Make sure the frequency is clear and then press the MOX button and advance the DRIVE until the meter just begins to deflect Press the METER switch to PO in 5 While still transmitting carefully reach around to the rear panel and adjust the FWD SET control for full scale deflection to the SET mark on the meter Move the FWD REV switch to REV and note the SWR reading on the bottom scale of the meter Set the MOX button off out a Again if the SWR is above 3 a change in the antenna system is recommended for operation on this frequency Power Meter Calibration The meter may be calibrated using the CW mode to indicate approximate transmitter RF output power in watts as follows This is necessary for proper transmitter adjustment for AM FM and RTTY or packet transmission and is help ful for reduced power operation in other modes If using the FC 757AT Antenna Tuner this procedure is not necessary as the FC 757AT includes a wattmeter and dummy load Before beginning measure the SWR as described above and make sure the antenna is properly matched or connect a 50 ohm dummy load 1 With the MOX switch off s
54. phone patch or AFSK tone generator Impe ance is 600 ohms and the level should be externally adjusted to match that of the oper ator s microphone producing the same power output with the same MIC gain control setting 14 FWD REV This switch selects meter indication of either forward or reverse relative rf power output during transmission when the METER switch on the front panel is in the depressed PO position Refer to the following description of the FWD SET control and the description of SWR measurement in the Operation section 15 FWD SET This potentiometer adjusts the sensitivity of the meter for forward and reverse PO functions during transmission Adjust this control for full scale meter deflection while transmitting a carrier with the FWD REV switch set to the FWD position so that SWR can be read on the meter in the REV position 16 EXT ALC This phono jack accepts transmitter automatic level control voltage from a linear amplifier for the transmitter when the transceiver serves as an exciter The applied voltage should be between 0 and 5V DC referenced to the outer contact chassis ground 17 AF OUT This phono jack provides constant low level receiver audio unaffected by the AF gain control for tape recording digital demodula tors capable of high impedance input or an external audio amplifier Output level is ap proximately 200mV peak at 50 kilohms 18 EXT SP External Speaker This 1 8 inch
55. r are provided to reduce or eliminate the various types of noise interference and distortion that can obstruct comfortable reception Oper ation is first described for SSB USB or LSB reception on an amateur band with variations for other modes described later Press the MODE button to select USB and tune to the 14 21 or 28 MHz phone band if your antenna is for a band below 10 MHz select that band and the LSB mode Also set the AGC F button for fast agc action depressed RF AMP amp Attenuator Careful adjustment of the receiver front end is necessary for optimum reception and should be treated as first priority at the start of an operating session or when changing modes bands or antennas To set up the receiver for optimum sensitivity first make sure the RF gain control is fully clockwise the rf amplifier and attenuator are off RF AMP and ATT undepressed On a clear frequency check for any S meter reading on the background noise level hiss or crackle If the S meter deflects above 3 turn on the attenuator press ATT Otherwise if the background noise gives no deflection turn on the RF AMP and again note the S meter reading on background noise if it is above 3 S units turn the RF AMP back off leaving it on would increase the S meter readings of received signals but would not improve the signal to noise ratio real sensitivity would increase the likelihood of overload from strong signals o
56. s IF Shift amp Notch Filter If you experience interference from stations on nearby frequencies after tuning in a station and setting the rf controls as just described rotate the SHIFT control to sup press the interference Usually interference on one side of the desired signal is worse than on the other and by shifting the pass band toward the clearer side reception of the desired signal can be improved Notice however that the passband of the desired signal is also shifted so turning the SHIFT control too far may cut off too much of the low or high audio components and make the signal unintelligible The IF notch filter is primarily useful for suppressing heterodynes in CW and ECSS recep tion as described later However it is also a powerful tool for suppressing other types of interference such as computer generated buzzing noise in the SSB mode After tuning in the desired signal and setting the SHIFT for optimum copy if you are receiving a buz zing type noise turn the NOTCH on out of the click stop and watch the S meter while tuning the notch control for minimum deflec tion on the noise when the other station isn t talking Of course this same technique can be used to suppress interfering CW signals or carrier heterodynes during SSB reception 19 Note once the NOTCH has been set adjusting the receiving frequency or the SHIFT control will move the notch setting which will then have to be readju
57. s and then switch on the power supply followed by the transceiver POWER switch The meter and dis play should light with the display indicating the default memory clear state VFO A and 7 000 0 Also the green GEN and yellow LSB indicators should light also defaults Press the H G key and observe the steps of the DWN and UP keys the GEN indicator is off for amateur band steps and then press DWN and UP keys to select the operating band for which the antenna is resonant The Ham Gen H G selection affects only the stepping action of the DWN and UP keys when tuning a vfo You can use either selection to receive on any frequency or to transmit in the amateur bands The transmitter is disabled outside of the 500 kHz amateur band segments regardless of Ham Gen selection Press the MODE button repeatedly if neces sary to select the desired mode of emission Turn the AF gain control clockwise for comfor table receiver volume If you do not have a scanning microphone yse the FAST button on the front panel to select course tuning steps with the tuning knob and then set the FAST button off undepressed for fine tuning Notice that both coarse and fine tuning steps are mode dependent as shown on page 6 If you have an MD 1B8 1 8 scanning mic rophone the scan keys on the microphone can greatly facilitate vfo tuning with the tuning knob operate the tuning knob with one hand while keeping your other hand on t
58. s an application program by itself but rather is intended to provide some ideas for a simple approach to CAT programming which should be combined with the users own concepts for useful applications This program is not copyrighted Anyone is free to use any part of the code for their own use For use in commercial applications acknowledgement of this manual as the source would be appreciated REM tae REM FT 757GXII CAT SYSTEM TEST REM FEISS ISI REM Initialize Serial I O Port of computer IOPORT 49344 REM Serial Data Port Address particular to FIF 65 A CMDPORT IOPORT 1 REM Serial Command Port Address FOR I 1 TO 3 POKE CMDPORT O NEXT I REM Clear IO chip 8251 USART in FIF 65 A for init CMDPORT 64 POKE CMDPORT 207 POKE CMDPORT 55 REM Init USART for 4800 baud no parity 1 stop bit HOME PRINT REM Clear the screen REM Display Menu of User Commands PRINT PRINT 0 Enter Frequency PRINT 1 1sb PRINT Maham aab PRINT 18 PRINT 4 PRINT MB RN PRINT 6 fm PRINT 7 PRINT 8 vfo B PRINT 9 Read Stats INPUT Select a number CMND REM Get command from keyboard IF CMND lt gt 0 THEN 600 REM Jump around for all except freq entry REM Get new Frequency test for valid range and retry if invalid INPUT Input new Freg decimal MHz FREQ IF FREQ
59. sted Another powerful application of the IF notch filter is to effectively narrow the receiving passband by tuning the notch near the high or low edge The result is illustrated in the diagram below First tune in the desired sig nal and adjust the SHIFT as described above Then turn on the NOTCH and adjust it to the opposite end of the passband from that rejec ted by the SHIFT for best noise rejection and receiving clarity Normal Passband Narrowed Notch Passband Remember to return the NOTCH control to its off clickstop position and the SHIFT con trol to its center position when retuning to another frequency Noise Blanker Pulse type noise either short duration types such as from ignitions systems and electric motors and switches or long duration over the horizon radar woodpecker signals can be reduced or removed by pressing the NB button and adjusting the NB control from coun terclockwise to clockwise just to the point where the noise is removed Rotating the NB control too far may cause distortion of the desired signal or intermodulation if strong signals are present on nearby frequencies When noise blanking is not required the NB button should be in the off out position Squelch All mode When waiting for a scheduled call on fairly uncrowded band the squelch can be activated to silence the receiver until the call Just tune to the scheduled frequency or set the scan ner as described later to
60. t selected mem ory or vfo Changes operating frequency mode Press while receiving on a vfo to use the selected vfo for receiving and vfo for transmitting the alternate SPLIT numbered memory or UP key to scan to the next higher numbered memory P will be displayed in place of the memory channel number indicating that the PMS system is now activated PMS scanning will pause automatically when the squelch opens or can be manually halted by the PTT switch or DWN UP keys the PMS function remains active P still displayed Press DWN or UP again to resume scanning When the SCAN MODE switch is returned to off out PMS scanning is cancelled and normal oper ation resumes on the last selected vfo which will be set to the frequency and mode last tuned during scanning While receiving press to switch operation between vfo and mem ory Also starts stops memory scanning during Scan Mode MR VFO VFO M VFO rM Press while receiving on vfo to write contents over last selected memory Operating frequency does not change Press while receiving on a memory to write contents over last selected vfo Operation shifts to vfo 28 SYSTEM COMPUTER CONTROL The CAT Computer Aided Tuning System in the FT 757GXII allows control of the frequency and mode of vfos and memories selection between them and signal strength detection and scan ning control
61. tching to an SSB mode for higher efficiency The VOX system and clarifier control can also be used for AM as described for SSB The AM CAR control on the rear panel adjusts the modulation percentage for a given carrier level This control is aligned at the factory to provide 10096 modulation when the DRIVE control is set for a carrier level of 25 watts and the MIC gain control is set to about the same position as required for full power output in SSB For 100 modulation with a lower carrier level the AM CAR control can be readjusted with an oscilloscope connected to monitor the RF output To set the AM CAR control for 100 modulation at full power output use an RF voltmeter for the following steps 95 1 Connect the RF voltmeter to jack 11023 the RF Unit Select a CW mode and note the voltmeter reading with the transmitter keyed 2 3 Return to receive select the AM mode key the transmitter and with no modulation adjust the AM CAR potentiometer for exactly one half of the voltage that was measured in the CW mode PI Unless using a heavy duty power supply keep transmissions short and stop transmitting if the power supply becomes hot RTTY HF Packet amp SSTV Transmission Transmission of narrowband FSK Fl RTTY SSTV and Bell 103 HF packet requires input of equal level audio tones AFSK at the 600 ohm PATCH jack on the rear panel Remove the microphone from the MIC jack
62. termodulation distortion better than 35dB below peak output 814 MHz 100W Reference oscillator stability better than 10ppm from 0 to 40 C after 15 minute warmup Modulation systems SSB CW active balanced modulator AM early stage low level FM variable reactance Maximum FM deviation 5 kHz RF Output impedance nominal 50 ohms unbalanced Microphone impedance 500 to 600 ohms RECEIVER Frequency range 150 kHz to 29 99999 MHz continuous Circuit type Triple conversion superheterodyne Clarifier range unlimited full receiver range Sensitivity for 10dB S N N exc FM 150 250kHz 250 500kHz above 500kHz SSB CW 1 0uV 0 5uV 0 25uV AM 10uV 4uV FM 0 5uV for 1248 SINAD above 500kHz Intermediate frequencies 47 060MHz 8 215MHz 455kHz Image rejection better than 70dB IF rejection better than 70dB all frequencies Selectivity 6 60dB SSB CW W amp FSK 2 7 4 5 kHz CW N 600 Hz 1 3 kHz AM 6 18 kHz FM 15 30 kHz Dynamic range CW N 814 MHz better than 10088 Maximum audio power output at least 1 5W into 4 ohms w 10 THD Audio output impedance 4 to 16 ohms GENERAL Supply voltage 13 5 VDC 10 Power consumption Receiver 2A Tramsitter 100W output 19 Dimensions WHD 238 x 93 x 238mm without feet or knobs Weight approx 5 2 kg 11 5 Ib Specifications may be subject to change with out notice or obligation ACCESSORIES Supplied Part No D
63. the power source or mode we recommend reducing power from the maximum levels mentioned above whenever transmitting for more than 10 minutes or if the ambient air temperature is very hot or the power supply feels hot AM Transmission Because carrier power is only one fourth of the total PEP of an AM signal it must be limited to 25 watts or less when transmitting with the FT 757GXII When the power of the modulating sidebands is added to the carrier power actual PEP output is 100 watts al though this does not show on the meter To adjust the FT 757GXII for AM transmission first calibrate the PO meter as described on page 26 or use an external wattmeter 1 Preset the MIC gain fully counterclock wise and set the METER switch to PO 2 Make sure the frequency is clear and then close the PTT switch on the microphone and advance the DRIVE for power output of 25 watts or less on the transmitted carrier 3 Set the METER switch to ALC out Speak into the microphone and advance the MIC gain control until slight movement of the meter occurs on voice peaks output is now 100 watts Do not advance the MIC gain further or overmodulation and dis tortion may result 4 Use the DRIVE control to reduce power once contact has been established The AF speech processor can be activated for AM transmissions by pressing the PROC button However if speech processing is necessary to maintain contact we recommend swi
64. tions the GND terminal on the rear panel of the transceiver should be connected by a heavy braided cable to a good earth ground Best performance on all frequencies may require that the grounding cable be less than 10 feet 3 meters long station equipment should have its own grounding cable independent of signal or con trol cables connected to a common point on the grounding bus close to the transceiver or linear amplifier if used See the diagram below 7570 Hes Ground Bus EARTH Locate the transceiver so that air can flow freely over the heatsink and under and behind the case Avoid placing anything on top of the transceiver and do not place the transceiver on top of another heat generating device such as a linear amplifier AC 234V 220 200V 17 100 FP 757HD POWER TRANSFORMER PRIMARY CONNECTIONS Antenna Systen The FT 757GXII is designed for use with any antenna system having 50 ohm resistive impe dance at the operating frequency Automatic final protection AFP circuitry is included in the transmitter to protect the final trans istors by automatically reducing power output when an impedance mismatch high SWR is present With an SWR of 3 1 for example only about 75 of full power output is available Despite this protection the FT 757GXII should never be switched to transmit when no antenna or dummy load is connected to the ANT ja
65. trol only after the other con trols have been set The FT 757GXII FM cir cuitry is designed for 5 kHz deviation as is most common in 2 way FM communications RTTY and Packet Reception An external TU terminal unit or TNC termi nal node controller is required for RTTY or packet operation respectively Receiver audio is best obtained from the AF OUT jack on the rear panel as the level of the signal at this jack is not affected by the AF gain control However your TU or TNC must be capable of high impedance input 200mVp p 50 kilohms to use this signal Otherwise low impedance out put is available from the EXT SP jack but this is affected by the AF gain control and using this jack disables the internal speaker The SHIFT control is especially convenient for RTTY and hf packet operation using the SSB modes generally LSB is used for amateur digi tal modes below 29 MHz Set the SHIFT control so that fsk tones are centered in the pass band the center position is 1500 Hz As for SSB the NOTCH filter may be adjusted to suppress an unwanted carrier or to narrow the passband after the SHIFT control has been set The agc should be fast AGC F depressed and the noise blanker may be left on at a moderate setting about 10 or 11 o clock Ee TRANSMITTER OPERATION The solid state transmitter in the FT 757GXIT requires no adjustment other than setting the desired output level The maximum power output is determined
66. tune for zero beat on the received carrier To hear the carrier set the SHIFT control all the way in the direction that gives emphasis to bass and very slowly tune for the point where the signal sounds most natural and undistorted with no accom panying whistle or dissonance When you have tuned to zero beat return the SHIFT control to center or adjust for minimum interference and the desired tone and push D LOCK so you don t loose the frequency Hint Zero beating an AM signal in ECSS recep tion requires a very careful touch on the tuning knob Some practice with stronger sig nals first will make tuning the weak ones easier Coarse tuning cannot be used for ECSS When receiving AM signals in either AM or ECSS mode the noise blanker should be off unless it is really needed Its effectiveness will vary depending on the signal strength of the received signal and those on adjacent chan nels being most effective when the signals are weak and noise pulses are strong FM Reception The FT 757GXII is equipped for FM operation without additional accessories However FM is generally not used on frequencies below 29 MHz so a VHF or UHF transverter may be used to extend the range of the FT 757GXII to the amateur bands above 30 MHz The SHIFT NOTCH Noise Blanker and AGC con trols are not active in FM reception However the RF AMP RF gain ATT and SQL settings are especially important For weak signal work set the SQL con
67. y monitored After transmitting if the cooling fan is on don t turn the POWER switch off until the set has had a few minutes to cool and the fan to switch off Memory Recall 1 Press MR VFO to recall memories the display and mode indicators will change to the last memory channel accessed 2 While watching the displayed channel number press the DWN and UP keys to select different memory channels The mode of emission of a recalled memory channel may be changed temporarily by the MODE keys When another memory or vfo is selected the tempo rary mode selection is cancelled Changing the frequency or the stored mode of the memory requires restoring from a vfo Changing Memory Mode amp Frequency To change the data stored in a memory channel it is necessary to shift the data to a vfo where it can be manipulated 1 Press MR VFO and the DWN UP keys to select the memory to be changed 2 Press MR VFO again to return to the vfo either A or B data will not be lost 3 Press 4 to exchange the vfo and memory contents 4 Now retune or change mode as desired 5 Press to exchange the vfo and memory again restoring the new data from the vfo to memory and original vfo data back from the memory to the vfo If operating on a memory and you don t care to preserve the vfo data you can just press M VFO to copy the memory channel data to the last selected vfo This leaves the memory data i
68. your local Yaesu dealer for Yaesu part no 01000010 0041 22803A or substitute any 8V 100mA pilot lamp Do not jumper across the lamp fuse terminals however as this will defeat the protection and could result in serious damage See picture below for the location of the lamp fuse LAMP FUSE INvVLLWVOIWV6e wys NVZ wyo wys Wve WvolWve wys Wvz wyo wys Nvv wye wyi ur INv9 Wyp Wye ws es vo wys wyr SN Wai 0002 wyo vs Wve Wve MEN Wat NYE Wat vs WdollNde Wd W Wve wyi Puen War Wvz SN 49 Wds WdS Wde Waz wys 0020 ueoNwvirWvOLWY6 wys wvz 0090 wye 0050 Wvorwve lwys o0vo wvolwve wys vo vv jooco ve Wve wys wve 0020 wys wv 9
69. ys the remaining controls for the receiver are provided to reduce or eliminate the various types of noise interference and distortion that can obstruct comfortable reception Oper ation is first described for SSB USB or LSB reception on an amateur band with variations for other modes described later Press the MODE button to select USB and tune to the 14 21 or 28 MHz phone band if your antenna is for a band below 10 MHz select that band and the LSB mode Also set the AGC F button for fast agc action depressed RF AMP amp Attenuator Careful adjustment of the receiver front end is necessary for optimum reception and should be treated as first priority at the start of an operating session or when changing modes bands or antennas To set up the receiver for optimum sensitivity first make sure the RF gain control is fully clockwise and the rf amplifier and attenuator are off RF AMP and ATT undepressed On a clear frequency check for any S meter reading on the background noise level hiss or crackle the S meter deflects above 3 turn on the attenuator press ATT Otherwise if the background noise gives no deflection turn on the RF AMP and again note the S meter reading on background noise if it is above 3 S units turn the RF AMP back off leaving it on would increase the S meter readings of received signals but would not improve the signal to noise ratio real sensitivity and would increase the likeliho

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