TS-120S_Technical_information_1979.pdf

itstrair io.1106 MitwoOkmwatmoi INCORPORATING KENWOODS HIGHLY SOPHISTICATED TECHNOLOGY A NEW LINE WITH A VARIETY OF OPERATIONAL ENJOYMENT HF SSB TRANSCEIVER MODEL TS-120S The new model TS-120S transceiver is an exciting addition to Kenwoods HF SSB line. It is expected to be very popular with novices and advanced Amateurs for a variety of reasons. In developing the TS-120S, the following goals were achieved: 1. Compactness and light weight, and yet incor- porating up-to-date technology for best per- formance, functions, and mobility in any fixed, mobile, or portable (such as Field Day) appli- cations. 2. High cost-performance ratio with more enjoyable HF operation, introducing up-to-date technology in the smallest possible package. 3. Easier operation so that all Amateurs, including newcomers, can enjoy HF communications without complex tune-up and operating procedures. As a result, a compact size (only 241 mm (91/2 W) X 94 mm (3-3/4 H) X 235 mm (11-9/16 D) and light weight (only 5.6 kg or 12.32 lbs. approx.) was achieved with- out sacrificing basic performance and pratical fea- tures required in an HF SSB transceiver. The following basic features were retained without com- promise: 1. Frequency coverage of 80m, 40m, 20m, 15m, and 10m bands for both transmitting and receiving. 2. Single-conversion system with advanced PLL cir- cuit. 3. Built-in digital display with 100-Hz readability. 4. Analog dial readable to 1 kHz. 5. Same effective built-in IF shift circuit as in the TS-820, to eliminate interference. FEATURES of the TS-120S 1. Easy operation The TS-120S has been designed so that even Amateurs who have no HF SSB operating experience can enjoy such communications with ease. Also, the TS-120S is a suitable HF SSB transceiver for exclusively mobile operation. Cumbersome tuning procedures such as peaking the drive, dipping the final plate current, antenna loading, and preselector tuning, as required on conventional HF SSB transceivers, are completely eliminated from the TS-120S. All the Amateur has to do is set the band switch to his de- sired frequency, and operate! 2. Extremely Compact The extremely compact TS-120S HF SSB transceiver offers performance that would be expected only in larger, more expensive transceivers. Newcomers and advanced operators will be fully satisfied with the performance of the TS-120S. Whether used as a fixed or mobile station, the TS-120S does not require much space, and many Amateurs will consider it to be the ultimate HF transceiver for their requirements. 3. Built-in Digital Display The digital frequency display, which until now was found only on large, expensive transceivers, is built into the TS-120S as a standard feature. The display uses a blue fluorescent tube for fatigue-free viewing over long operating sessions. The operating frequency can be read without error. Furthermore, the analog subdial helps the operator determine at a glance the operating frequency. 0 RIT INDICATOR ANTI VOX CONTROL DELAY CONTROL 0 CARRIER LEVEL CONTROL MIC CONTROL 0 AF GAIN CONTROL OD VOX GAIN CONTROL 0 SUBDIAL 0 METER tb-t CA* ?AP ?af 0 DIGITAL DISPLAY 0 RF GAIN CONTROL %Mk 0 STANDBY SWITCH 0 MODE SWITCH 0 MIC CONNECTOR 0 PHONES JACK 0 VOX SWITCH 0 METER SWITCH 0 FIX SWITCH 11 MAIN TUNING KNOB CI BAND SWITCH IF SHIFT CONTROL POWER SWITCH 011) NOISE BLANKER SWITCH CALIBRATOR SWITCH 01) RIT SWITCH 0 RIT CONTROL 0 GND TERMINAL 0 DC POWER CONNECTOR 0 CW KEY JACK 0 ANT CONNECTOR 0 COOLING FAN 0 EXT VFO CONNECTOR 0 SPEAKER JACK REFERENCE FREQUENCY ADJUSTMENT ACCESS REMOTE CONNECTOR 4. IF Shift System The same advanced IF shift (passband tuning) system as used in the TS-820 series transceivers is also provided in the TS-120S. This system removes ad- jacent frequency interference and sideband splatter. Kenwoods advanced PLL engineering efforts have made it possible to build the IF shift system in such a compact rig as the TS-120S. Besides removing adjacent frequency interference, the IF shift system makes it possible to adjust the pitch of CW signals being re- ceived. 5. Built-in VOX Circuit A built-in VOX system is provided in the compact TS-120S. Also, the built-in CW sidetone oscillator circuit and VOX system makes semi-break-in operation available in the CW mode. 6. Innovative M.C.F. The monolithic crystal filter has the same outstanding char- ? ?CC) acteristics as the normal eight ? 9 pole crystal filter but occupies ? 8 a much smaller space. ?Fig. 1 shows the Characteristics of the SSB filter and CW filter. In addition to the built-in SSB filter, a sharp CW filter (YK-88CW) is also available as an option. FREQUENCY IN kHz Fig.1 7. All Solid-State Construction The TS-120S is a high-performance transceiver with all solid-state design, including the transmit final power amplifier stage. The transmit final amplifier stage includes a protection circuit that detects VSWR and temperature, automatically reducing output to 1/10 of normal output when either parameter is too high. Extra consideration is given to the ra- diation of final-transistor heat. A specially de- signed die-cast aluminum heatsink and a quiet fan with a temperature-detection device allow high, yet stable power output, while retaining compactness. 8. Built-in Noise Blanker The same effective noise-blanker circuit as used in the TS-520 and TS-820 series is also a standard feature in the TS-120S. This eliminates pulse- type interference generated by car ignition systems, particularly on the higher HF bands. A new type of filter in the input circuit of the noise blanker minimizes the effect of adjacent-frequency signals on the operation of the blanker. 9. Built-in Fixed Channels Four fixed channels are available, with one channel on each of the 7, 14, 21 and 28 MHz bands. Fixed channel operation on the 3.5 MHz band is possible by changing an inside connector, which changes the position of the crystal from 28 MHz to 3.5 MHz. Operation can be changed from VFO to fixed channels by selecting the VFO-FIX switch on the pannel. 10. Built in 25-kHz Marker The 25-kHz marker signals are derived from the 10-MHz master oscillator and provide an accurate frequency reference for the TS-120S or other rig. Circuit Configuration Shown in the block diagram (Fig. 2), the TS-120S uses a single-conversion system with a new PLL circuit which does not require a crystal element for each band. 1. Receiver Station The incoming signals from the antenna are, after passing through the IF trap circuit, boosted by about 10dB by the wideband transformer and supplied to the bandpass filter (B.P.F.) for each band. The B.P.F. is composed of three coils and Fig. 3 shows its circuit configuration, of which typical charac- terisitics are shown in Fig. 4. A preselector is unnecessary with the B.P.F. and therefore the RF BLOCK DIAGRAM Fig.2 Fig.4 Typical B.P.F. characteristic NB GATE -0i- XF 1st IF AMP 2nd IF AMP 3rd IF AMP 0 100 80 BPF ?RF AMP Buff AMP MIXER E CERAMIC FILTER f 14.175MHz INPUT 0dB AF OUTPUT 0.63V AT8S2 a, 60 -0 z 40 w 20 0 20 ANT C7 A Fig.5 ? FREQUENCY N MHz RF Amp stage frequency response Fig.6 Receiver level diagram section including the coil pack is very compact. This B.P.F. circuit is used in common both for transmission and reception. The signals through the B.P.F. go into the wideband RF amplifier, composed of 3SK74 and 2SK1815 dual-gate MOSFETs. This amplifier boosts the signals by about 20d6 between 2 MHz and 35 MHz. Fig. 5 shows the frequency characteristics of the wideband RF amplifier. The RF amplifier-output is fed to the balanced mixer (made up of two 3SK74 dual-gate MOSFETs) through a wideband transformer and is then converted to the 8.83 MHz after being mixed with the VCO output from the PLL circuit. The converted signals proceed, into the 10.0 100 - IMAGE RATIO ? IF RESPONSE 5.0 90 80 70 0.5 FW- 1(8 60 O 5W 40 0.1 20 1 ?3.5 ?4 ?7 ?7!5014 14.5 15021 ?21.5428 28.5 29 29.5 10 14 14.5 A 1 ? 21.5 28 28.5 29 29.5 30 30 0.0 Fig .7 ? CARRIER FREQUENCY IN MHz Receive sensitivity Fig.8 ? CARRIER FREQUENCY IN MHz Receiver spurious response IF unit and are applied to the crystal filter through the gate circuits of the ceramic filter and noise blanker. The gate of the noise blanker is turned on or off by blanking pulses that are am- plified, detected, and ordered, with noise separated by changing AGC threshhold levels. ?In actuality, the noise blanker works effectively to eliminate the pulse-type interference generated by car ignition systems. As a result, even weak signals can be re- ceived clearly with no noise. The noise blanker is operated by the NB switch on the front panel. The signals coming through the crystal filter are amplified by about 90dB by the three-stage IF amplifier (3SK74 MOSFETs), and are demodulated into audio signals by the four-diode ring detector. ?The AGC circuit de- tects and amplifies the signal from the last IF stage through the buffer amplifier, with the time constant determined by a 2.2 Mohm resistor and a 1 AJF capacitor, and controls gain by applying that signal as the AGC voltage to the second gate of the RF amplifier stage and three-stage IF amplifier. The level of gain controlled is indicated on the S meter, as the Smeter circuit measures AGC voltage directly. The S-meter circuit also functions as the ALC meter circuit when in transmit mode. The antenna input levels of approximately 2 dB (0.6)uV) and 34 dB (25JaV) are set at S1 and S9 respectively. The level diagram of each receive stage is shown in Fig. 6. ?The signal received, now transformed into an audio signal, is amplified by one stage and again voltage-amplified by the MA1366W IC after coming through the AF volume control, and then drives the speaker. A portion of the AF output is used as a signal for ANTI VOX, which prevents the VOX from being activated by the output from the speaker. Fig. 7 shows receiver sensitivity. ?Receiver IF spurious response and image rejection are shown in Fig. 8. Fig. 9 and Fig. 10 show two-signal response characteristics in the receiver. Fig.9 TS-120V Receiver two signal response charaeteristic 120- DESIRED SIGNAL INPUT LEVEL 20dB 100 r- Nu ea. W- W- 14.175MHz SSG2 ? LOAD 80 ? V.T.V.M UNDESIRED SIGNAL n- 0 ? 6100 400 200 0 ?200 400 600 FREQUENCY DIFFERENCE IN kHz UNDESIRED SIGNAL INPUT IN dE SSGI 40 - DESIRED SIGNAL a) 14.2294H, rci 14.250.111 SSGI ri 100 SSG2 Fig.10 modilation U) U) 0_20 ANT input level 100 (in db) SSG-1 100 tl 50 3 0 Q4 10 O =1.1.MMINIMME.41. Photos 2 through 6 show harmonic spurious data for each band. The fundamental signal from the filters passes through a CM-type SWR detection circuit. In this cir- cuit, detection sensitivity is relatively flat between 3.5 MHz and 29.7 MHz because the current transformer utilizes a toroidal core, with very little insertion loss. Forward power is detected at one end of this toroidal coil and reflected power at the other. If standing waves are present, the reflected-wave voltage detected at one end of the coil is amplified and ap- plied to the ALC circuit as a protective voltage to control power output. The second gate of the common FET in the IF is controlled by the ALC voltage produced by amplifying the voltage detected at the forward- power end of the toroidal coil. The cooling fan begins to operate when the final-unit heatsink temperature rises because of operating conditions and/or ambient temperature, etc., whether in transmit or receive mode. Heatsink temperature may rise abnormally high during long transmissions if cooling efficiency de- teriorates because of air-flow blockage by surrounding objects. In this case, the TM 1, 2 thermostat ac- tivates, disabling the transmitter and placing the transceiver in receive mode. Normal operation resumes when the heatsink temperature is lowered to the ambient level. Fig. 14 shows power output characteristics for each band. Fig. 15 shows output power and ALC voltage characteristics for mic input level. ? Issi ?lot ?Cs! ?lot as ?.7 ?.3 1t ? 14.35 2 1 ?21.45 VI V? ?30 Frequency (MHz) Fig-14 0.5 1 ?10 Mic input level(mV) Fig-15 100 50 a) 3 0 O 10 4) O 5 0 Physical Design of the TS-120S The TS-120S has been made as compact as possible while re- taining all functions formerly found only in much larger transceivers. As a result, HF mobile activity and port- able operations, including DX-peditions, are expected to increase in popularity. In designing the TS-120S, the following goals were achieved: Ruggedness, compactness, and light weight High cost/performance ratio Easy-to-operate .panel layout and construction Attractive appearance Compactness was achieved with absolutely no sacrifice in high performance. For convenient mobile installation as well as desk-top operation in a limited space, the trans- ceivers depth was kept as short as possible. Dimensions are only 91/2 inches wide by 3-3/4 inches high by 11-9/16 inches deep. Weight is only 12.32 pounds. Such compact- ness was achieved by: Advanced circuit design, using the latest solid- state technology External power source (transceiver operates on 13.8 VDC) Compact VFO design and improved installation New panel layout and smaller parts Internal Construction A single (monolithic) chassis is used, because there are no heavy parts such as transformers. The low-pass filter and the final stage are installed lengthwise on the rear. Single-chassis construction is achieved by a new tech- nique that provides both transmission and reception simply by switching the bandswitch, using a bandpass filter for each band. Variable tuning capacitors for dipping and loading are unnecessary, thus simplifying the RF stage configuration. Switching low-pass filters is necessary with the transis- torized final stage. The filters and switch are located on the printed-circuit board. Differential gears on the subpanel mechanically connect this switch to the shaft of the rotary band switch. This configuration allowed greater flexibility in the design of the panel layout and internal construction, resulting in a high cost/per- formance monolithic chassis. VOX controls are located on top of the cabinet, in the center. The AF GEN unit is floated by the heatsink mounting hardware and, there- fore, VOX controls come direct from the unit. A 3-inch speaker is installed on top of the cabinet, front right. The cabinet is finished in an attractive dark gray color with a metallic tone. A metal stand that mounts flush with the cabinet bottom pivots down to tilt the TS-120S when used as a base station. Panel An aluminum die-cast panel provides additional ruggedness and light weight. The VFO, operating controls, and in- dicators (digital frequency display and meter) are laid out at the center, right, and left, respectively. The microphone connector, send/receive switch, and mode switch are located at