Improved noise figure & dynamic range on bands > 21 MHz.! New Quad-JFET 1 st Mixer " Doubly-balanced design with higher LO drive offers much-improved dynamic range & strong-signal handling. Pro2 4ĥ IC-756Pro III Front End Redesign! New RF BPF board " larger inductors and better diodes, to reduce strong-signal IMD.! New RF Preamp 1 based on IC-7800 design " Low-noise, push-pull BJT circuit with larger coupling transformers and negative feedback has better linearity and lower power gain without degrading noise figure.! New RF Preamp 2 with hot transistor " f t = 3.5 GHz. IC-756Pro II! Technological & Performance Improvements: " Much stronger receiver front end employing IC-7800 technology " Improved DSP algorithms: better Noise Reduction (NR), CW filters and QSK! New Mini-Scope screen presentation: " Spectrum scope normally occupies lower half of screen, but can be switched to halfheight to allow display of 3 fields instead of 2 (frequencies, scope and menu or bargraph meter scales.)! Programmable SSB TX occupied-bandwidth settings " Upper & lower cutoff frequencies of WIDE, MID, NAR TX audio response selections can be set independently:! Lower: 100, 300, 500 Hz.! Upper 2.5, 2.7, 2.9 khz.! Miscellaneous new features: " Improved EMC filtering in DC power feed " Improved RX-ANT input excess-power protection " Stock 60m band SSB TX coverage (5 US channels, 1 UK channel) " Storage for 8 canned RTTY messages (up to 62 characters each) " Dual clock display with programmable time offset " New ITU symbol " Screen-saver (black field with programmable owner callsign) NSARC HF Operators 756Pro3 vs. Pro2 3Ĥ Summary of IC-756Pro III Improvements vs. More details follow NSARC HF Operators 756Pro3 vs. Complete front-end redesign for +30 dbm IP3 (50 khz). Adjustable Noise Blanker threshold.! IC-756Pro III (2004): Further improvements over IC-756Pro II. RX tasks: all above + improved front end, selectable DSP IF filter shape factors, CW filters available in data modes, dedicated RTTY filters. Voice record/playback.! IC-756Pro II (2001): Many improvements over IC-756Pro.
TX tasks: all above + FM modulation, compression, IF-level Monitor, selectable SSB occupied bandwidth & CW rise-time. RX tasks: All above + AM/FM demodulation, variable IF filters & tunable notch (no crystal filters), RTTY decode. Also: 4.9 LCD display screen, Spectrum Scope, Dual Watch, ATU, DDS synthesizer.! IC-756Pro (1999): First 100% IF-DSP Icom transceiver. TX tasks: Modulation (except FM), Mic Equalization.
RX tasks: Demodulation (except AM/FM), Noise Reduction, Auto Notch, CW APF. Pro2 2ģ Brief History of the Icom IC-756 Series! IC-756 (1997): Hybrid design analogue IF, crystal filters, 15 khz IF-DSP.
Pro2 1Ģ Pro III and Pro II compared IC-756Pro III IC-756Pro II NSARC HF Operators 756Pro3 vs. the Pro II Adam Farson VA7OJ IC-756Pro3 Information & Links Copyright 2006 North Shore Amateur Radio Club NSARC HF Operators 756Pro3 vs.