Attenuator: 0 dB, –10 dB, –20 dB and –30 dB.The processing power in the IC-7851 allows for dual mini band scopes as well as the audio scope. On receive, you can see the power of your filtering by watching filtering adjustments take out interfering signals including filter width and notch filter placement. Adjust your transmit audio by watching your compressor level, equalization and mic gain settings to give you the audio you want for SSB. The audio scope simultaneously shows an oscilloscope and FFT for receive and transmit audio. *4 SPAN=5kHz, SPEED=Slow Audio scope function *1 Number of dots shown at 60dB level, when receiving a signal The 2250 MFLOPS DSP processor enables a new dual scope function and significantly faster sweep speeds and better accuracy than in the IC-7800. Improved spectrum scopeįollowing the design linage of the IC-7800, the IC-7851 uses a dedicated DSP unit for the Fast Fourier Transform (FFT) spectrum. An impressive 20dB improvement is seen with the IC-7851's 10 kHz measurement and more than 30dB improvement at a 1 kHz measurement in comparison to the IC-7800. Phase noise is coherent in radio circuit design and the new LO design introduced in the IC-7851 makes some major breakthroughs while utilizing the 64MHz, up-conversion receiver design introduced in the IC-7800. LO C/N Characteristics Comparisons 1st LO 14.1MHz This design significantly reduces noise components in both receive and transmit signals. The C/N ratio excels beyond the IC-7800 and other similar class HF transceivers. This newly developed filter overcomes the gap of a narrower roofing filter in an up-conversion receiver.Ĭrystal clear LO (local oscillator) designīreaking the boundaries of traditional designs, the IC-7851 employs a Direct Digital Synthesizer (DDS) along with a Phase Locked Oscillator for the LO. The IC-7851 introduces a new 1.2kHz Optimum Roofing Filter, greatly improving the in-band adjacent signal performance. A flat consistent performance is delivered over a wider frequency range. In an up-conversion receiver, suppression of image interference and reduce distortion from electric components is easily overcome. Roofing Filter IC-7800 = 3 kHz, IC-7851 = 1.2 kHz 1.2 kHz Optimum roofing filterĭespite the trend to switch to a down conversion or a hybrid conversion receive design, Icom believes in the solid per performance of the up-conversion design. Receiving frequency: 14.2 MHz Mode: CW, IF BW: 500 Hz Below is a comparison of the improvement over the IC-7800. The goal was to dramatically reduce the phase noise that degrades the target signal due to the sum of the entire signal present. RMDR: 110dB raising the barĭesign advances developed by the Icom HF engineers for the Local Oscillator (LO) enable the IC-7851 to set a new benchmark for amateur radio receivers. Adding this performance and functionality for both receivers give you a dual scope portal. In addition to the incredibly clean LO allowing you to hear the weak signals, the new spectrum scope design enables you to see the weak ones! Faster processors higher input gain, higher display resolution and a cleaner signal from the receiver's LO will give you a new window into the RF world. As a result of this design, the purity of the LO achieves a Reciprocal Mixing Dynamic Range (RMDR) of 110dB. With the design of the IC-7851, Icom's engineers focused on a new Local Oscillator (LO) that drastically reduces the phase noise. However, what happens inside the radio with all those signals coming down your feedline can defeat all your efforts. Larger antennas, higher gain pre-amps and other devices in line are great. HF/50MHz Transceiver - The Pinnacle of HF Perfection Solid design basics and HF expertise raising the barĬontesters and DXers are always looking for that competitive edge to magically pull out the weak signal that is either the rare country or multiplier they need to climb up the list.
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