Kenwood TS-990S manual Transmit, Built-in automatic antenna tuner capable of high-speed operation

HF/50MHz TRANSCEIVER TS-990S Transmission unit /cooling

Transmitter performance,

Built-in automatic antenna tuner capable of high-speed operation

featuring high-scale specifications,

can withstand long periods of operation at full power.

Operating stably even when continually working over long periods of time, such as in competitions.

Transmit

The built-in automatic antenna tuner is a preset type that covers amateur band frequencies rang- ing from 160m~6m, and is completely operable during receive. The tuner is capable of rapid QSY based on instantaneous band change, using

arelay system known for high-speed operations. The relays, capacitors, and inductors use large- sized components that are able to bear the 200 W output.

It is outfitted with four antenna terminals, which can be set independently on amateur bands, whether main band or sub band. The reception input and output terminals can be used for reception dedicated antennas, antenna output for external reception devices, and external BPF connections. It is usable with either the main band or the sub band.

	ANT				RX OUT		RX IN
1	2	3	4
			MAIN BAND				MAIN
			ANT Selector			MAIN RX ANT	BAND
					RX	OFF	RECEIVER
				AT		ON
					TX	SUB RX ANT	SUB
			SUB BAND			OFF	BAND
							RECEIVER
			ANT Selector
						ON
							Transmission Unit

High reliability design promises stable operation at 200 W

Cooling system to send a sufficient volume of air to each unit

Cooling is very important to obtain a stable output of 200 W. Heat dissipation efficiency is increased

The POWER MOS FET VRF150MP runs at 50 V in push-pull. You can obtain a stable output of 200 W on all bands. You achieve superior IMD properties by pursuing bias and matching conditions in order

3rd order TX IMD 14.2 MHz / 200 W
-10
-30
-50
-70
-90
10 dB / div	SPAN 10 kHz

to fully exploit the FET attributes. Further, you can realize Kenwood’s distinctive tone by amplifying the clean modulated signal produced by DSP with an amplifier that exhibits excellent linearity.

in the TS-990S through a large fin-type aluminum heat sink. An independent variable-speed fan is provided for the switching power supply, final unit, and antenna tuner, cooling each unit with a sufficient air supply. The switching power supply and the final unit have twin cooling fans. Noise is reduced by controlling the fan speed according to the temperature.

Thermal Simulation Example

To dissipate the heat of the 200 W final, we used swage fins instead of the conventional extruded aluminum fins. Using CAE analysis, we designed the optimal fin shape and size for heat dissipation.

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