A signal of less than 1 µV is visible, whilst the 756 requires at least 20 µVto produce a spike. The vertical sensitivity of the 756Pro Spectrum Scope is significantly higher than thatof the 756.
#Icom 756 pro ii cable manual
The fact that all the DSP IF filters, including the Manual Notch(but excluding the Auto-Notch) are inside the AGC loop sets the Pro (and the late,lamented Kachina 505) apart from all other amateur HF transceivers on the market. Also, the DSP IFfilters are inside the AGC loop, so strong signals outside the DSP filter bandwidth willnot swamp the receiver. With the Pro, you can optimise the IF bandwidth by tailoring it to the occupiedbandwidth of the received signal, thus yielding optimum S/N ratio. The manual notch is alsohelpful in improving the SNR of the received signal. The ability to tailor thefilter passband to the received signal (using the Twin PBT or the filter tables) also provides a superb tool for pulling out the "weak ones". I am able to copy easily SSB signals which do not move the S-meter.Those signals would have been barely intelligible on the 756. The measured sensitivityon 20m with Pre-amp 1 on, and 500 Hz bandwidth, is 0.1 µV for 10 dB S+N/N (using an HP8640B generator). Overall, the Pro pulls the "weak ones" out of the noise noticeably betterthan the 756 (or any of its other predecessors in my shack) did. These are clearly due to the NB gatingon signal peaks, and are eliminated by switching the NB out. I observe significant artifacts under strong-signalconditions only when the noise blanker is enabled. The combination of the DSP-NR and noise blanker renders night-time 40m listeningmuch more pleasant and less fatiguing.
The DSP-IFfiltering, including a tuneable notch filter, is all inside the AGC loop (unlike theIC-756). It makes an S9+20 undesired tone disappear off the S-meter. The manual pre-AGC IF notch filter (70 dB deep) isdynamite. Also, read George's "Notes on roofing filters" (below). George, W5YR's IF Filter Page dramatically illustrates this point. The DSP IF filters have much steeper skirts than the analogue crystalfilters in the older rig, and are much more effective against adjacent-channel QRM than analogue filters. I find the Pro a big improvement over its predecessor, the 756.The Pro receiver seems much quieter than that of the 756 - probably due to a cleaner DDSLO implementation. In July 2000, I sold my IC-756, and bought a 756Pro from a local dealer. In the IC-756Pro III, it is possible to program each of the three settings individually with the following preset cutoff frequencies: Lower -6dB point: 100, 300 and 500 Hz., Upper -6dB point: 2.5, 2.7 and 2.9 kHz.Adam, VA7OJ/AB4OJ's IC-756Pro User ReviewĪdam, VA7OJ/AB4OJ's IC-756Pro/Pro II User Review The lower and upper -6dB points of the transmitted audio-frequency response are fixed for each setting.
The IC-756 Pro II provided three selectable TOBW settings: WIDE/MID/NAR. Soft and sharp filter shapes can be selected in both SSB and CW modes independently, Programmable SSB transmit bandwidth, microphone equalizer, manual notch function, digital twin pass band tuning (PBT), all mode, including PSK31. 32-bit floating point DSP Digital IF filter with 51 selectable bandwidths. Real-time spectrum scope with mini-scope.
#Icom 756 pro ii cable plus
121 position microphone equalizer.Ĭovers the nine HF bands and 60-meter plus 6 meters. Soft and sharp filter shapes can be selected in both SSB and CW modes independently, microphone equalizer, manual notch function, digital twin pass band tuning (PBT), all mode, including PSK31. 32-bit floating point DSP Digital IF filter with 41 selectable bandwidths, microphone equalizer, manual notch function, digital twin pass band tuning (PBT), all mode, including PSK31.Ĭovers the nine HF bands plus 6 meters. All successors required no additional filters.Ĭovers the nine HF bands plus 6 meters. 4.9 inch monochromatic TFT dot matrix LCD display.
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