Kenwood TS-140S (1987)

A compact HF transceiver that ARRL's lab pushed well past its published receiver limits - and that still sells for reasonable money on the used market.

Overview

The TS-140S is a 160-10 meter amateur HF transceiver from Kenwood, sold under the Trio-Kenwood name out of Komagane, Japan. Radiomuseum's collection index lists the model year as 1987. QST Magazine ran a full product review in June 1988 on a unit with serial number 8101427. Some sources list the radio as plain "Kenwood TS-140," and the available documentation doesn't make clear whether that's shorthand for the "S" or a distinct variant. Treat the two names as the same radio unless a seller can show otherwise.

Functionally it's a general-coverage HF transceiver covering all amateur bands from 160 through 10 meters, with SSB, CW, AM, and FM modes. Kenwood's own materials describe the receiver section as covering 500 kHz to 30 MHz with "superior dynamic range." The ARRL Lab measured something else during the QST review. It found the receiver tuning from roughly 50 kHz to 34.9999 MHz, far beyond the manufacturer's published claim. So the radio will hear signals outside the band edges Kenwood advertised. QST (June 1988) documented both figures in the same review, so both are kept here rather than treated as a contradiction.

The transmitter side is rated at 100 watts on HF. QST's review lists the SSB output at 110 W PEP. That number comes from a bench measurement rather than a marketing sheet, and it suggests the 100-watt rating is a conservative floor rather than a hard ceiling.

Key Features

Dual 10 Hz Step Digital VFOs

Two independent digital VFOs, each stepping in 10 Hz increments, give the operator split-frequency capability without a separate external VFO. That's what you want for DX work and split pileups. You can listen on one frequency and transmit on another without juggling.

Adjustable Scanning Speed

The scan rate is operator-adjustable. A fixed scan speed is often either too slow to be useful or too fast to catch anything, so letting the operator set it is the right call.

Built-In Antenna Tuner and DSP Filtering

The TS-140S carries a built-in antenna tuner and DSP filtering. On a compact HF rig, the tuner removes one box from the operating position and one cable from the back of the desk. The DSP section is late-1980s DSP, not the brick-wall filtering of a modern SDR, but it's there and it does something.

RF Amp, Attenuator, and Processor

The front end includes an RF amplifier, an attenuator, and a speech processor. The attenuator matters on a general-coverage receiver this sensitive, since strong local signals will overload a receiver without one. The processor is for the transmit side, and the RF amp is for weak-signal work when band conditions are poor.

Slide Controls for RF Output, Mic Gain, and NB Level

Three slide controls handle RF output, microphone gain, and noise blanker level. Slide pots on a front panel are a period signature, and by the 1990s most manufacturers had moved to rotary controls or menus. Whether you prefer slides is a matter of taste, but they're fast to grab and easy to read at a glance.

50-Ohm Antenna Input with PL-259

The antenna input is 50 ohms, and Kenwood's documentation specifies a 50-ohm coaxial cable terminated with a PL-259 connector. That's the standard HF amateur interface, nothing exotic and nothing proprietary.

Compact, Lightweight Chassis

Kenwood and several used-gear listings describe the TS-140S as compact and lightweight, with front-panel controls laid out strategically for easy operation. The digital frequency display and the light chassis make it a reasonable candidate for mobile or field operation as well as a fixed station. The rear panel carries several I/O jacks, which is more connectivity than the size suggests.

Collectibility & Value

The TS-140S hasn't crossed into collector territory the way some Kenwood HF rigs have, but it's not forgotten either. Universal Radio's used page shows one sold at $299.95, and the radio has a small following among operators who've run one. Brenton Meadows of Aussie Radio Pickers called it "one very underestimated radio that packs enormous punch, & a superb receiver to boot."

Used parts do surface. Original internal speakers and knob encoders have both appeared on the used market. No common failure modes or maintenance procedures are documented in the available sources, so buyers should evaluate a specific unit on its own merits rather than expecting a known-issue checklist. Prices in the $300 range for a working example seem reasonable, though the market for 1980s HF transceivers moves slowly and condition matters more than the model number.