Kenwood TS-820 manual Block D I a G R a M, General, Transmitter Section, Receiver Section

Page 25

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5.1BLOCK D I A G R A M

GENERAL

The block diagrafl Of TS - 820 is shown on page 24.

The transceiver is composed of the single superheterodyne receiver and the single conversion type transmitter with a fil-

. ter type SSB generator. It uses 8.830 kHz IF and its local oscillator is equipped with a PLL (phase locked loop) circuit controlled by VFO. Both the receiver and transmitter use balanced type mixer circuits with dual gate MOS FET's.thus minimfzing spurious during transmission and preventing the effects of strong signals and suprious signals during recep~ tton.

Taking full advantage of PLL system. the transceiver offers IF SHIFT functlon (electronic system pass band tuning1 and permit one SSB filter t o provide the same effect obtained by US8 and LSB filters. The transcetver also includes a number of latest accessory circuits such as the RF speech processor. the digital display circuit (option), transmit monitor circuit. etc.

This signal 1s fed to the IF unit, passes through the nolse blanker circudt and the crystal filter. and is finally amplified by the 3-stage IF amplifier. so that it is converted Into AF slgnal by the ring detector.

The AF signal 1s applted lo the AF-AVR unit where it is am- pl~fiedto the level to drive the speaker The frequency c h a ~ iacteiistic of the AF amplifier is automatically changed t o suit CW or SSB operation by means of the MODE switch.

TRANSMITTER SECTION

The microphone signal is fed to the IF unit, amplified by the microphone amplifier and is then fed to the ring modulator composed of 4 diodes. The DSB output from the modulator passes through buffer amplifier and the crystal filter. The SSB signal thus obtained is further amplified and fed to the transmit mixer of the RF unit.

The transmit mixer is a double balanced type mixer with 2 MOS FETs The local oscillator is VCO type (voltage control- led oscillator) whose output is controlled by the PLL circuit t o minimize spurious during transmission. The SSB signal converted into the wanted transmit frequency is amplified by the transmit driver tube 112BY7A) before being fed t o the two S2001A power amplifier tubes of the final stage.

They operate in class AB 1 because of low distortion amplifi- cation fo SSB signal.

The output signal is transm~ttedthrough a pi-network t o the antenna.

RF NFB is applied from the output of final stage to the driver stage to further reduce the cross modulation distortion.

RECEIVER SECTION

The antenna signal passes through the RF A l l switch. where it is attenuated by about 2 0 dB as necessary, and is then amplified by the RF unit.

The amplified signal is fed to the buffer amplif~erand mixed with VCO output in the balanced mixer with 2 MOS FETs to produce 8.830 kHz IF signal.

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Contents Operating Manual Contents Mode WWVAudio Input Impedance Audio Output ImpedanceSection FeaturesPower Connections InstallationUnpacking Operation LocationKEY HeadphonesExternal Speaker a N D Rtty FS KAC Operation ANTSuitable PTT Microphone Front View Panel Operating Controls@ VFO Indicator @ Meter Switch@ Stand by Switch @ ATT Indicator@ N B Switch VOX SwitchC Switch C Connector@ Function Switch @ B a N D Switch@! H. S W Heater Switch @ Power SwitchRear Panel View Display Hold Switch@ Drive Knob @ Plate KnobRear PAN EL Controls @ Remote Connector External VFO Connector@ DC-DC Converter Connecting Hole PIN FunctionOperating Instructions Preliminary ProcedureReceiver T U N I N G Reading the Operating FrequencyRF G a l N Calibrating T H E FrequenciesCalibrating the Fixed Channel a N D VFO Freciuencies Calibrating the T S 8 2 0 W I T H VFO-8209NOISE Blanker If ShiftAGC a U T O M a T I C Gain Control 1 Transmitter T U N I N GFront Panel Controls ALCUP on 3 C W O P E R a T I O N 2 SSB O P E R a T I O N5 Fixed Frequency Operation 4 Operation W l T H a Linear AmplifierMobile Operation 6 Internal Cross Channel Operation9 Rtty Operation Function TransmitSstv Slow Scan TV Operation USE of Monitor SwitchOperation with a Phone Patch Novice OperationTS-820 Block Diagram General Block D I a G R a MTransmitter Section Receiver SectionBoard a N D Unit Coil Pack Board PLL Unit Counter Assy Unit Display Unit Display Unit OptionAF AVR Board I N a L Stage Power Amplifier General Information Maintenance and AlignmentInstalling the D C D C Converter IDS AccessoriesI b l Transverter TV-5021 Remote Connections Extension Feet Fixed Channel Crystal InstallationAdjustment of Receiver Section Adjustment of T R a N S M I T if Coil if a N D RF Units Adjustment of Transmitter SectionCarrier Balance Adjustment if UNIT1 Neutralizing the Final StageGeneral Information TrolibleshootingTransmitter a N D Receiver Circuits Receiver SectionTransmitter Section SymptomsFAN TOP & Bottom View of the TS-820Page IO--KENWOOD Corporation

TS-820 specifications

The Kenwood TS-820 is a high-performance amateur radio transceiver known for its exceptional features and technologies that cater to both novice and experienced operators. This rig, part of Kenwood's renowned TS series, has become a popular choice for those seeking reliability and versatility in their communication equipment.

One of the defining characteristics of the TS-820 is its dual-conversion superheterodyne receiver architecture. This design minimizes interference and provides improved performance across various amateur radio bands. With coverage from 160 meters to 10 meters, the TS-820 is capable of operating on all major HF amateur bands, making it an excellent choice for diverse communication purposes.

In terms of power, the TS-820 delivers a solid output of 100 watts, ensuring that operators can make their presence known across the airwaves. The rig features a built-in automatic antenna tuner, which simplifies the setup process by matching the transmitter to various antenna types. This feature not only enhances signal clarity but also maximizes the station's efficiency.

Another standout feature of the TS-820 is its extensive digital signal processing (DSP) capabilities. The advanced filtering options help to eliminate noise and interference, allowing users to hear weaker signals more clearly and effectively. The IF filter selections can be adjusted to optimize reception under varying conditions, showcasing the rig's adaptability.

The user interface of the TS-820 is designed for both ease of use and functionality. The large, backlit display provides critical information at a glance, while the rotary controls offer tactile feedback, allowing operators to make precise adjustments quickly. Additionally, the rig supports various modes of operation, including SSB, CW, and RTTY, accommodating a wide range of communication preferences.

Built with durability in mind, the TS-820 utilizes high-quality components and construction techniques that ensure long-term reliability. Its rugged design can withstand the rigors of everyday use, making it a trustworthy companion for any amateur radio enthusiast.

In summary, the Kenwood TS-820 is a versatile and reliable amateur radio transceiver that stands out due to its superior performance, advanced technologies, and user-friendly features. With its robust design and comprehensive capabilities, the TS-820 continues to earn its place as a respected choice among ham radio operators around the world. Whether engaged in casual conversation or competitive contesting, enthusiasts can rely on the TS-820 for a satisfying and immersive amateur radio experience.
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