FT-991A

Roofing Filter for enhanced performance

The Yaesu FT-991A includes a 3KHz and 15KHz roofing filters for the triple conversion receiver that effective attenuates interfering signals and enables outstanding performance while still producing high quality audio.

Yaesu FT-991A receiver block diagram

These narrow band roofing filters are especially useful on a very crowded band during contests, because they can dramatically attenuate powerful out-of-band signals in the first IF stage and reduce their impact in the second stage to further optimizing the excellent dynamic range and IP3 characteristics for processing signals ranging from faint to powerful.

Real-time Spectrum Scope with ASC

The real-time spectrum scope gives radio operators the ability to graphically view the location of signals on the band while they listen to the received audio allowing them to quickly move to the desired signal. The strength of signals on the band can readily be seen on the multi-color waterfall display. Chronological order color differentiation allows operators to easily recognize weak signals at a glance; signals that might otherwise be missed on the spectrum scope.

Yaesu FT-991 real-time Spectrum Scope (left) and multi-color Waterfall Display (right)

Also, the advanced spectrum scope with ASC (Automatic Spectrum-Scope Control) located just below the LCD display gives the operator all the information for comfortable QSO on the DXing scene.

Useful function

Versatile array of functions for CW operation: Advanced electronic keying (4-60 wpm) with FULL BK-IN support, electronic Keyer weight control (2.5-4.5), CW side tone pitch frequency adjustable (300-1050 Hz), message Memory function (5 channel x 50 characters), APF function with 3-stage bandwidth selection improves Signal-to-Noise ratio for enhanced intelligibility, auto Zero-in function facilitates subtle tuning operations for CW, automatic Beacon keyer mode, CW SPOT feature, CW mode reversal. Convenient functions for FM mode: 104 types of DCS (Digital Code Squelch), 50-tone CTCSS encoder/decoder, ARS function provides easy repeater access. Other features: Speech processor, 5-channel digital voice Message memory function for repetitive voice messages, MULTI dial design facilitates setting operations, VOX, MOX, 99 channel memory, RTTY/ DATA Jack, USB port allows connection to a PC with a single cable for CAT control / Audio In-Out interface, Carrying Handle, Tilt Stand.

Solid Performance

The RF Amplifier in the Yaesu FT991 provides a clean and solid 100 Watts of Operating Power (50 Watts on 144/430 MHz) and is combined with a large heat-sink and forced air automatic cooling fan to increase operating time and prevent overheating. Internal high-speed Automatic Antenna Tuner (ATU) included in the package. The antenna tuner uses a LC switching network that has a large capacity 100 channel memory. The tuning data is automatically memorized to reduce tuning time when changing frequency.

FT-991A DSP circuit :

The high speed floating point DSP device TMS320-C6746 (3000 MIPS / 2250 MFLOPS) from Texas Instruments (TI), makes possible excellent interference rejection with actual signals under real-world conditions, not only in the HF but also in the VHF and UHF bands.

Yaesu FT-991 32-bit High Speed Floating Point DSP (left), Contour Filter Conceptual Diagram (top-right), Digital Noise Reduction Perfomance (bottom-right)

The IF-Width and IF-Shift functions are the basis for removing interfering signals and are easily implemented for the best effect. The efficacy of interference rejection is further enhanced by sophisticated functions inherited from the FTDX transceiver series, such as the 16-stage digital noise reduction (DNR) and the auto-notch filter (DNF) that rapidly tracks even multiple heterodynes. The Contour function that enhances the desired signal with a natural sound, and the Notch function with selectable bandwidth, along with other functions are provided for comfortable and convenient DX and QSO operation.

FT-991A receiver circuit :

Features the highly acclaimed quad mixer of the FTDX series transceivers, along with a dedicated VHF/UHF mixer. The 1st IF mixer for HF/50 MHz features a quad mixer with 4 x 3SK294 dual-gate MOSFET devices that assure extremely low noise (NF), excellent intermodulation characteristics (IMD), and high dynamic range (DR). A dedicated VHF/UHF mixer, separate from the HF bands, permits design optimization for targeted frequencies, and results in superior performance characteristics.

Yaesu FT-991 Roofing Filter, HF/50 MHz Quad Mixer, VHF/UHF Mixer

RF amplifier design is optimized for each band. The IPO, AMPI and AMP2 selections for the HF/50 MHz bands allow matching the settings to the current band and conditions, to ensure optimal RF amplifier operation. The RF amplifier for the 430 MHz band uses HEMT (high-electron-mobility transistor) NE3509 devices which maintain good performance into the GHz range, and combine high gain with a low NF.

Yaesu FT-991 Dynamic Range and IP3 characteristics,
14 MHz Band / CW mode / BW=500 Hz / Roofing Filter 3 kHz / 20 kHz Spacing

Final stage with ample Power reserves; 100 Watt for HF/6m Band and 50 Watt for VHF/UHF Band. Using a push-pull arrangement of RD100HHF1 MOSFET devices, renowned for excellent performance in the HF/6m range, the amplifier delivers 100 W of low-distortion, high-quality power. High speed 1.8 to 54 MHz antenna tuner included as standard equipment. The high speed ATU employs relay switching and features a large 100 channel tuning data memory. This allows the user to instantly call up optimum matching conditions for previously used frequencies.

Yaesu FT-991 VHF/UHF final MOSFET device

50 Watt amplifier for VHF/UHF assures plenty of power for high frequency bands; the final amplifier for the VHF and UHF bands uses the high-output RD70HUF2 MOSFET which incorporates two devices in a single package, providing ample output power of 50 W.

FT-991A parametric equalizer :

The MIC amplifier equalizer feature is equipped with a three-stage parametric equalizer that can alter the Low, Mid, and High frequencies of the audio separately. This feature permits the bandwidth and gain for each part of the audio spectrum to be precisely adjusted independently. You may utilize one group of settings when the speech processor is Off and use an alternate group of settings when the speech processor is On.

Yaesu FT-991 Parametric Equalizer Menu and Parametric Gain

The configuration aspects that may be adjusted on the Parametric Equalizer are Center Frequency (the center frequency of each of the three bands), Gain (the amount of enhancement / suppression), Q (the bandwidth over which the equalization is applied).

FT-991A advanced C4FM functions :

This transceiver C4FM mode provides good error correction perfonnance, and supports the V/D mode (voice/data simultaneous transmission mode) which makes the transceiver suitable for mobile communication, and the Voice FR (full rate) mode which allows the radio to transmit high quality digital audio. The AMS function recognizes the contacting stations transmission method and automatically switches the transceiver to the same C4FM digital or analog (FM) communications mode as the received signal.

DG-ID (Digital Group ID) / Group Monitor (GM) feature enables automatically locating, and communicating with other stations that have the same number within contact range. The two-digit DG-ID numbers (00...99) can be set separately for Transmit and Receive. By setting both transmit and receive to 00, communication with all the other stations in the C4FM mode is possible, regardless of their number setting.

DP-ID (Digital Personal ID) feature may communicate only by the transceivers registered the individual ID information. Every C4FM transmit communication contains the individual ID information (Radio Identification) of each radio set. The function uses this individual ID information. When the DP-IDs of the transceiver are registered with each other, they can communicate even if the Digital Group ID numbers are different. By registering the DP-ID of the transceiver to the DR-ZX System Fusion 11 digital repeater. the digital repeater may be controlled by remote operation.

FT-991A high stability built-in TCXO :

The 30.225 MHz standard oscillator provides exceptional frequency stability. It is temperature compensated and boasts an enhanced +/-0,5 ppm stability from -10°C to +50°C.

FT-991A custom selection button :

This feature lets you select any Menu item for one-touch access via the C.S button.

FT-991A rear panel and connections :

Yaesu FT-991 rear panel and connections

FT-991A price

We have collected for your convenience the Yaesu FT-991 sale price (US Dollar) and its trend over time. Useful to guarantee a cheaper purchase of this radio and to put it for sale in the second-hand market. Of course offers, accessories, warranty terms and conditions can lead to different figures.

Price	Date	Condition
USD 1299.95	2023-mar	Brand-new 3 Year manufacturer warranty
USD 1129.95	2021-feb	Brand-new Store special offer