Kenwood TS-990SHF manual Main Receiver, Newly developed mixer contributes to achieving +40 dBm IP3

The TS-990S has the overwhelmingly highest quality receiver among the TS series.

We have achieved a down-conversion format for all amateur bands

The dual receivers facilitate reception on different bands.

The main receiver is the highest quality receiver among the TS-900 series, thanks to its down-conversion configuration, newly developed mixer,

and five types of roofing filters. The highest quality transceiver shows its true metal in contests, fierce pile-ups and high-intensity signals.

The TS-990S will surely satisfy any real DX’er.

A key point in tapping maximum performance from the 1st mixer in actual operation (say, CW operation) is to prevent the outflow of unnecessary signals, other than the target signal, from the mixer to the subsequent stage. This is because it can tap the maximum per- formance of the digital IF filter using the DSP in the final IF stage. The TS-990S main receiver employs a 1st IF frequency 8.248 MHz down-conversion format. It achieves superior close-in dynamic range unattainable through conventional up-conversion formats. Even if the interference is a close-in frequency, the receiver maintains a relatively flat dynamic range, which you can tune without losing your target signal.

Comparison

3rd order Intercept Point characteristics

	50.00
	40.00
[dBm]	30.00
	20.00
Point
	10.00
Intercept	0.00
	-10.00		TS-990S
	-20.00		Our old model
	1	10	100

Interfering wave separation [kHz]

frx=14.2MHz,PRE AMP OFF,BW 500Hz,MODE CW,

The horizontal axis shows separation of the target signal by interfering signal frequencies (two waves). At a frequency of 10 kHz, interference 1 refers to reception frequency + 10 kHz, and interference 2 refers to reception frequency + 20 kHz.

The newly developed mixer contributes to achieving +40 dBm IP3

In place of the Double Balanced Mixer, which uses the J-FET, we have installed the newly developed Double Balanced Grounded Switch Type in the 1st mixer circuit, which is the heart of the main receiver.

The transceiver is also equipped with a pre selector function (works on HF amateur band) that varies its tuning frequency in tandem with the receiver frequency. It effectively dampens interference from strong signals that cannot be minimized through bandpass filters on dedicated amateur bands. Furthermore, we have achieved a +40dBm class of third-order intercept point for the signal path of the 1st mixer, based on select circuits and components, employing large core toroidal coils for protecting against distortion from large input signals, as well as using relays for the signal switching.

RF BPF

through

ATT

0/6/12/18dB

Pre Selector

Main Receiver

			Pre Selector 160m BAND
	(dB)	0
		-20
	Amplitude
		-40
		-80
		-60
		-100
		0.0	1.0	2.0	3.0	4.0	5.0
				Frequency(Hz)
Amateur band RF BPF	Pre Selector feature							Transformer feedback RF Amp

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