> Interesting I worked there for 11 years 1989 until 2001 doing product > support and never heard of any recall. The 756 PRO is the first version of this ground breaking radio and the brochure describe.Adam, VA7OJ/AB4OJ's IC-756Pro III User Reviewsipasmer.web.fc2.com Icom 756 Pro 3 Serial Numbers Adam, VA7OJ/AB4OJ's IC-756Pro III User Review Adam, VA7OJ/AB4OJ's IC-756Pro III User Review Initial observations (July 2005) On June 30, I picked up my new IC-756Pro3 (S/N 32025XX) at a local dealer.Icom Ic 7000 Serial Numbers Icom 775dsp Manual I rest my case. If you own an ICOM IC-756 PRO transceiver, you may want a mint condition original sales brochure to go with it. Icom Radio News Number 5 1 of 2. FTdx1200 HF rig and go back to the Icom radios I loved, the 756 Pro. Bushmaster serial number manufacture date.Icom 756 Pro Iii Serial Numbers - heregload. ICOM IC-756PROIII SERVICE MANUAL Pdf Download ManualsLib. There were a few with encoder troubles that were some not being Icom Ic 7000 Serial Numbers Adam, VA7OJ/AB4OJ's IC-756Pro III User Review Initial observations (July 2005)Used, a ProIII is around 1500.Features.On June 30, I picked up my new IC-756Pro3 (S/N 32025XX) at a local dealer. See the May 2002 issue of QST for a great review of this radio. The IC-746 Pro came with HM-36 hand mic, spare fuses, OPC-025 DC power cable and key plug. The 746 Pro requires 12 VDC at 23 Amps.Overall, I would judge that the S/N ratio is better than on the Pro2, even in the presence of power-line noise. The NR and NB appear to have been significantly improved. I was able to work a number of SSB stations on 40m which I would not have heard on the Pro2. Preliminary findings are that it pulls weak, noisy signals out of the noise somewhat better than the Pro2.
Icom 756 Pro 3 S Serial Number Manufacture DateIn the Pro3, the preamps have been designed for highly linear large-signal handling, consistent with a low noise figure. S9 + 60 dB signals 1 to 2 kHz above and below our channel edges did not produce any perceptible artefacts in the received audio.When switched in, Preamps 1 and 2 do not raise the audible noise level in the receiver as much as they did in the Pro2. In addition, the Pro3's strong-signal behaviour appeared to be excellent. I am able (by using a combination of NR, NB, Twin PBT and Manual Notch) to squeeze intelligible copy out of the assorted "garbage" on the band more effectively than on the Pro2. The next day, I was able to sustain the sked with my friend Matt KK5DR somewhat longer, as the Pro3 "hears" signals buried in the noise somewhat better than the Pro2 did. Display qualityI have the impression that the Pro3's TFT display is superior to that of the Pro2. By being able to leave the bar-graph meter on-screen along with the scope, I learned that compression peaks at 6 to 7 dB when it only shows 2 to 3 dB on the much slower moving-coil meter. There are two clock displays - UTC and local - and a simple screen-saver which displays the owner's callsign moving about on a black background. In this test, MDS is defined as the RF input power which yields 3 dB unweighted S/N at the output. SSB and CW "Sharp" filter shapes selected.1: MDS (Minimum Discernible Signal). Offset tone pitch = 1 kHz (SSB), 600 Hz (CW). NB off, NR off, ATT = 0 dB, AGC MID. The test setup was as follows:HP8640B signal generator, calibrated against R&S URV4-03 RF power meter with 0 dB probe Sinadder 3 configured as true RMS audio voltmeter connected to jack. A few measurementsAs the ARRL, RSGB and others have already subjected the Pro3 to exhaustive test suites, I felt that any such effort on my part would be redundant (apart from the fact that my second signal generator is much too "dirty" for meaningful RF 2-tone measurements!)To satisfy my own curiosity, though, I ran a few quick receiver tests: MDS, reciprocal mixing noise and filter shape factors. Folder lock version 773 serial keyThus far, I have been using default settings, but plan to do more experimentation. This capability, along with the bass and treble equalisation menu, offers many intriguing possibilities. Programmable SSB transmitted occupied bandwidth (TBW)As in the IC-7800, the upper and lower -6 dB points of the transmitter audio-frequency response are independently programmable. This is an approximate measurement, as the amount of noise reduction is dependent on the original signal-to-noise ratio. This, added to the improvements in the receiver's RF chain, may explain the improvement in weak-signal handling with NR on (as noted above.)Ref.1, Section 5-2-1, describes NR in greater detail.More on NR: Normally, I leave the NR control at 50 to 60% in SSB mode, with AGC = MID.It knocks down the band noise by about 20 dB, but does cut the treble response somewhat as is to be expected. George W5YR has contributed an article on this topic to my IC-756Pro/Pro2 User Review.I have a sneaking suspicion that the NR process in the Pro3 reinitialises itself automatically every 15 sec. Keying the transmitter reinitialises the NR process, creating a perception of improved NR efficacy. Non-correlated noise) becomes "acclimatised" to the prevailing SNR and becomes less effective over time. Noise Reduction (NR)It has been reported that the Pro2 NR's heuristic correlation-discrimination process (correlated signals vs. A quick check has confirmed this. The low-frequency rumble reported in the 756Pro has been completely eliminated in the 756Pro3.Q: Is the information in the IC-756Pro/Pro II User Review on the BPF Indicator and CW filter settings also applicable to the IC-756Pro III?A: Yes, it certainly is. I listened to an S0 to S1 CW signal with BW = 50 Hz (SHARP shape factor, BPF on) and obtained very pleasant single-signal copy, even at that narrow bandwidth setting. This is particularly noticeable when using the narrow IF filters (500 Hz and less).The "background" is much quieter, and the "ringing" effect previously reported in the 756Pro and 756Pro2 (especially with CW Pitch < 600 Hz) is almost inaudible in the Pro3. Improved CW receptionThe received audio in CW mode is much more pleasant to listen to, and less fatiguing, than on the 756Pro2 or 756Pro. The noise reduction obtained with BW = 500 Hz and above is still useful. (At the time, I was listening to CW signals varying in level between S0 and S5.) When I operate CW, the NR control stays at 50%. These products "muddy" the transmitted audio. In addition, the practice of "force-feeding" - deliberately boosting the low-frequency portion of the baseband - can drive the speech amplifier into non-linearity, generating harmonics which mix with the mid-band speech components to yield a rich harvest of intermodulation products. 250 Hz robs transmitter power (remembering that an SSB transmitter is peak-power-limited) without contributing to the articulation at the receiving station *. This objective should be achieved in a manner that conserves transmitter power, and ensures that the available power is concentrated in that portion of the human speech spectrum which most influences articulation - typically about 350 ~ 2700 Hz at the -6 dB points.Excessive transmitted energy below approx. Only by "slicing away" the low end with 2.4 kHz IF BW and Twin PBT was I able to recover intelligible audio - and the S-meter reading dropped from S7 to S2!It should also be noted that the 15 to 18 kHz high-end response of some "broadcast-type" mics is wasted on a system which is 6 dB down at 2900 Hz and 13 dB down at 2950 Hz. Just a low-frequency rumble was audible in the headset. Especially when using compression, the lower -6 dB point should be no lower than 250 to 300 Hz (corresponding to the default MID TBW setting).* In one extreme case recently encountered on 20m SSB, the low-end "power-grab" was so severe that the distant station's lows swamped the AGC, rendering the signal unintelligible.
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