IC-756PROIII

IC-756PROIII HF/50MHz All Mode Transceiver (Discontinued)

The IC-756PROIII incorporates many of the features that made its predecessors so successful. However, the integration of the latest technology employed in the IC-7800 such as receiver technology, +30dBm class IP3, miniscope makes this new rig the very pinnacle of the IC-756PRO series.

SSB transmit bandwidth adjustable
The built-in audio equaliser has separate bass and treble adjustment for a total of 121 combinations, so you can tone your voice up or down when you want. In addition, the SSB transmit bandwidth is selectable from 100, 300, 500Hz at the high-pass edge, and 2500, 2700, 2900Hz at the low-pass edge respectively. 3 types of high and low combinations can be stored in the memory. With this flexibility of DSP based waveform shaping, transmit audio quality is adjustable depending on the operating situation.

+30dBm class IP3 (in 14MHz band), Excellent distortion resistance characteristics
The IC-756PROIII design focuses on distortion-free receiver performance. Basic analogue and digital technology used in the IC-7800 has been incorporated into the IC-756PROIII receiver. The front-end mixer at the RF stage is designed in a 4-element configuration. At the BPF switching stage, diodes which have superior wide dynamic range frequency characteristics and distortion-free characteristics are used.

Magnetic saturation sometimes occurs in traditional coils when a strong signal is received. To avoid this magnetic saturation, large inductors have been used at the RF stage.

The 15 kHz crystal roofing filter uses the same component as the IC-7800 in the fundamental mode to provide good distortion-free characteristics. Finally, each stage’s level distribution behind the 1st mixer stage and the AGC gain are optimised. The IC-756PROIII realises +30dBm class IP3*. (in 14MHz band)
* Under the following conditions: Receive frequency 14.2MHz, Input frequencies 14.3MHz and 14.4MHz, Pre-amp OFF, mode USB BW: 2.4 kHz

Newly designed pre-amplifiers
The IC-756PROIII has two pre-amplifiers, which offer advantages in bad band conditions. Both pre-amplifiers of the IC-756PROIII have basically the same circuit construction as the IC-7800’s preamplifiers. The preamp-1 is a noiseless feedback type with push-pull amplifiers. It has a high intercept point and covers a wide frequency range. The preamp-2 is a high gain pre-amplifier using bipolar transistors. It offers excellent advantages in using narrow band antennas such as a small loop or short Yagi antenna. This combination will provide the optimum receiver performance under any conditions.

Real time spectrum scope with mini scope function
The real time spectrum scope is now an indispensable tool for high-class HF radios. The IC-756PROIII’s spectrum scope adds the mini scope function answering the many requests from end users to add this feature. The mini scope function allows you to monitor the scope screen while you are using other function menus. For example, you can monitor the scope screen even while you are changing the IF filter shape or other level settings. The scope range can be set in 4 steps 12.5 kHz, 25 kHz, 50 kHz and 100 kHz, centred on the receiving frequency. In addition, the spectrum scope has 3 levels of attenuator (10dB, 20dB and 30dB).

8 channels of RTTY transmit memory
The IC-756PROIII has 8 channels of RTTY transmit memory. You can edit up to 62 character pre-fixed messages for each memory channel without a PC or other external unit. The transmit memory is displayed on the screen so that you will not send the wrong message. The built-in RTTY demodulator and decoder allow you to check the callsign of the station instantly. It is not necessary for you to prepare an external demodulator when you receive an RTTY message. The twin peak audio filter controlled by the DSP Unit reduces the interference, which appears between tones. The tuning indicator visually assists you to zero-in to the RTTY signal, which makes important tuning more easy.
* When transmitting an RTTY message on site, a Terminal Unit, TNC or PC and dedicated software is required.

@ code for memory keyer
The 4 memory keyer messages store often-used CW sentences. Each memory has up to 55 character capability. The “@” code used in e-mail addresses can be sent from the memory keyer. The “@” code, (• – – • – • –) has been added to the International Morse code list recently. In addition, the serial contest number can be counted automatically. 19 cut number function is included.

RETAINED FEATURES
32-bit floating-point DSP and 24-bit AD/DA converter
The 32-bit floating-point DSP and 24-bit AD/DA converter maximises the IC-756PROIII digital capabilities. This makes it possible to work a lot of digital features. In practice, the AD/DA converter realises surprisingly wide dynamic range. It provides clean and clear transmit, and crystal clear audio reception.

AGC loop operation
The digital IF filter and manual notch are included in the AGC loop controlled by the DSP unit. It basically rejects blocking by extremely strong adjacent signals out of the filter pass bands. Therefore, you will rarely suffer from blocking of the AGC gain. In addition, the AGC constants are easily adjustable for each operating mode.

Sharp and soft IF filter shape are independently selectable for SSB and CW mode
Sharp and soft IF filter shapes for SSB and CW have become part of the DSP unit programming. You can change the filter shape to pick up desired signals, even while listening to the signals.

SSB sharp filter; for selectivity and audio quality
The ideal filter shape factor and flatness in the receive bandwidth, that only DSP can achieve. This setting eliminates adjacent signals that are out of the intended bandwidth, and reproduces the signal in the bandwidth with high fidelity. This is ideal for ragchew and placing importance on the receive audio quality.

SSB soft filter; improves the clarity of weak signals
This filter has a rounded filter shape. It keeps down the band noise in high and low frequencies, and improves the signal-to-noise ratio. This setting makes it easy to distinguish very weak signals, even in low level noise, especially in the 50MHz band. This filter also has sharp skirt characteristics, similar to the SSB sharp filter

CW sharp filter, ultimate sharpness
The ideal ‘sharp’ filter shape factor, only digital technology can bring you. This setting is suitable for picking up weak DX signals in crowded band conditions. The signal quality, not seen with analogue filters, can be clearly recognised.

CW soft filter; broadens the filter skirts This filter improves the audio quality at
the edge of the filter skirt. This setting is useful when you run into pileups in contests or in DX peditions.

Digital Twin PBT
The digital twin PBT, using the DSP unit, narrows the passband width to efficiently reduce interfering signals by in 50Hz steps. IF passband width, IF shift width and IF shift direction are indicated on the LCD display for easy recognition.

RF speech compressor
The 32-bit DSP is used for the RF speech compressor providing the maximum punch without the fuzzy sound. Even when the compression is set at a higher level, the IC-756PROIII increases the readability without distortion. The tone gradation is very similar to the original sound so that the IC-756PROIII provides excellent audio at any compression level.

IC-756PROIII Additional Features
• 2 clocks ... the IC-756PROIII has 2 clocks built-in which show both local and UTC time at once
• Screen saver function ... when the IC-756PROIII has not been operated for a while, a screen saver will be shown on the display