ICOM IC-7851 – ALL THE DETAILS

Take the DXer to follow a weak signal, biggest enemy is the interference caused by strong signal of proximity frequency. This is an index is RMDR (Reciprocal Mixing Dynamic Range) characteristics of strength against interference, in amateur radio of the world, it can be said that never can be ignored important factor.

Icom is, in order to the pinnacle of amateur HF transceiver, in IC-7851, worked as the biggest challenge the RMDR gains from phase noise improvement of local oscillator.As a result, of different dimension over the prior machine much RMDR: 110dB ^※ I have reached a tremendous area of (typical).

In addition, a narrow-band filter of 1.2kHz with excellent IMD characteristics: OPTIMUM ROOFING addition FILTER has been adopted, dual scope to exert power in the contest and DX hunting, for example, equipped with a waterfall of unprecedented high-speed & high-resolution, IC-7851 is equipped with a future of overwhelming performance worthy to lead a new era of flagship machine and function.

DX front of an increasingly intense. If you seek the best outcome in the forefront, your choices just one. Icom is the IC-7851 to release long-awaited.

Phase noise characteristics is the largest factor of proximity interference in IC-7851, pursued to the limit. The performance priority than the cost, and has adopted the direct output method from DDS to all of LO. In addition, we have adopted the root become reference oscillator (10MHz) and Phase Locked Oscillator optimal component and the circuit was selected carefully to clock generation circuit, such as the DDS of the master clock. These, still achieves the LO of unprecedented high Purity. RMDR: 110dB ^※ (typical) that you can not reach the area you could not talk in a conventional machine. ※ 1kHz detuning (reception frequency: 14.2MHz, MODE: CW, IF BW: 500Hz, IC-7800: roofing 3kHz, IC-7851: roofing 1.2kHz)

The RMDR

RMDR (Reciprocal Mixing Dynamic Range) and an index of the “the effect of blocking the strong input signal closer to the phase noise associated with the LO of the receiving circuit, or the receiving sensitivity is how much worse.” The larger the number I indicates that the effect of blocking is less. The more general LO phase noise is small, this property is excelente.Upconversion is like [the image interference can be easily suppressed] [uniformity of performance can be obtained in a wide band] [easy to reduce the distortion that occurs in coils, capacitors, etc.], there is a large benefit HF transceiver. While taking advantage of the benefits, as proximity anti-jamming, Icom is top priority to the performance than the cost, excellent 1.2kHz narrow band filter of IMD characteristics in 1st IF stage of the 64MHz band: OPTIMUM ROOFING FILTER carefully adopted. Thus, to suppress the generation of distortion (IMD) caused by a plurality of signals to be close. I have realized the proximity dynamic range that surpass even the downconversion adopt machine.

OPTIMUM ROOFING FILTER characteristic diagram

In IC-7851 LO I was also working to further improve the purity of the (local oscillator). By using the Phase Locked Oscillator and DDS of high-precision, high-Purity, was greatly improved the Purity of local oscillation output. The result is obvious if you look at the following. Even compared with the IC-7800 came a high reputation in the world and boasts a different dimension of C / N characteristics. This excellent C / N characteristics has led to better quality of the transmitted radio waves not only receive.

Of local oscillator C / N characteristics comparison

Measurement conditions / radio display frequency: 14.2MHz MODE: CW 1st LO frequency: 78.655MHz 
SPAN: 20 kHz RBW: 30 Hz VBW: 10 Hz

 

Coordination process of the latest DSP and CPU software, and by the FFT processing by the DSP, and has realized the overwhelming sweep speed and resolution. Its performance has reached the level that can be read the sign of the CW from the display screen. Weak signal also, more quickly, and displays in more detail.

• Scope dedicated DSP 
  TI made ​​TMS320C6745 
  32-bit floating-point 
  maximum processing speed = 2250MFLOPS 
  internal clock operation at about 370MHz

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• Scope performance comparison

 

Main specifications of the FFT scope / waterfall

· ATT / 0dB, -10dB, -20dB, -30dB 
and only · FFT scope, waterfall simultaneous display of selectable 
choice of display type of · FFT scope (outline / fill), can display color setting

Main specifications of the oscilloscope

-LEVEL / 0 dB, -10 dB, -20 dB, -30 dB 
-1DIV / 1 ms, 3 ms, 10 ms, 30 ms, 100 ms, 300 ms 
-display color setting Allowed

Our amateur radio and has realized the dual scope display during the first two waves simultaneous reception. Because you can monitor two bands different at the same time, it demonstrates the tremendous power at the time condition of understanding and contests. In addition, the display of the dual scope, you can choose the up and down or left and right to suit your situation and needs.

By connecting the mouse to the USB port on the back, by linking the band scope and mouse operation, you can quickly access to the desired signal. In addition, such as changing the mode switching and sweep speed of FIX and CENTER, it is possible to operate reliably in the mouse a variety of scope function.

• <Scope operation example with the mouse> 
  ■ Frequency movement by left-clicking. 
  ■ click (left and right either possible) tuning with the mouse movement while the. 
  ■ Temporary frequency movement by the right-click 
  (to just kill click back to the original frequency).

Icom ic-7851 Manual

 * Google Translate   – Japanese to English

 

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