My IC-781, and its Successors An IC-781 graced my shack from mid-1993 until late 1998. I found that it was lacking in adjacent-channel selectivity on SSB, so I installed the 'NATO' filter mod - FL-44A in lieu of FL-96. I also replaced the stock FL-102 with an FL-223 for narrow SSB.
Then, I bought an 'original' IC-756. Glance Feat Mandinga Cinema Zippy. The 756, with its DSP NR, outgunned the 781 + outboard NIR-12 on weak/noisy signals, and offered superior adjacent-channel selectivity with the FL-222/223 SSB filter pair installed.
ICOM IC-718, serial number 001069 Manufacturer’s Claimed Specifications Measured in the ARRL Lab Frequency coverage: Receive, 0. Livro Medidas Caseiras here. 03-30 MHz; Receive, as specified1; transmit, 1.8-2, 3.4-4, transmit, 1.8-2, 3.5-4, 7-7.3, 10.1-10.15, 7.0-7.5, 9.9-10.5, 13.9-14.5. 17.9-18.5, 14-14.35,18.068-18.168, 21-21.45, 20.9-21.5, 24.4-25.1, 28-30 MHz. Policy Change: Icom America and its Icom Service Centers will now support and validate warranty repairs based on the serial number. What this means for you: The. Icom 775dsp serial number Post by n4rrh » Wed Jan 02, 2008 9:53 pm I have been told to look for a Icom 775 with the 2 or higher serial. The new Icom IC-7700. The previous serial number ranges begin with '0' e.g. Connecting an Icom Radio to a PC *. Install Ipa Font Windows 7 here.
So I reluctantly let the 'old girl' go. Whilst living in Florida, I was an NCS on the Icom Users' Net (formerly 14317 kHz, Sundays, 1700Z) for several years. At times, adjacent-channel interference became a severe issue, what with our frequency sandwiched between the 'hot-spots' which used to occupy 14313 and 14322 kHz. The Icom Net has since moved to 14.316 kHz, to get away from the fourth harmonic of the TV colour-burst. Even with the 'NATO' filter upgrade and the FL-223, the ACI and splatter would sometimes overwhelm the 781. I found that the IC-756's cascaded 1.9/1.8 kHz narrow SSB filters (FL-223/222), together with Twin PBT, did a better job of 'pulling out' the desired signal than the IC-781. Another situation which frequently arose was trying to copy a check-in station running barefoot to an indifferent antenna; often, his signal was in the noise.
I found that the DSP noise-reduction feature of the IC-756 often resolved these weak signals well enough for Q4 to Q5 copy, when they eluded the 781 - even with an outboard JPS NIR-12 audio DSP box. It should be noted that reciprocal mixing noise (a function of DDS spectral purity) is a very strong attribute of the IC-781. On 20m, with 10 kHz offset, the measured reciprocal mixing noise 'numbers' for the IC-781 are 1 dB better (RF preamp off) than those of its competitor, the Yaesu FT-1000D, and 11 dB better with RF preamp on. The IC-781 uses the same DDS synthesiser chipset as the IC-275 family of VHF/UHF all-mode radios. In 2000, an replaced the 756, and I found it even better all around.
It even has a tuneable pre-AGC notch filter, unfortunately omitted from the 756. I then brought back an from Dayton 2002. The Pro II had significantly improved as compared to the Pro. An replaced the Pro II in mid-2005.
The Pro III is superior to the Pro II in many ways. Here is a of the Pro II vs. In mid-2008, an replaced the Pro III; it is the receiver/exciter in my current.
There is no gainsaying DSP-based HF radio architecture. Defence suppliers such as, and have been using DSP for years in their HF equipment. It is only in recent years that DSP chipsets have reached a price/performance level accessible to the amateur community. Radio architecture is now at the point where classical analogue designs are no longer cost-effective to manufacture, and DSP will only get faster and better. However, analogue radios (such as the IC-781) will still be available in the second-hand market for years to come. From the ham radio standpoint, the IC-781 was an accident of history which turned out very well indeed. Icom developed this radio under a defence contract; soon thereafter, the ham community 'discovered' its incredible performance - way ahead of the pack at the time - and its unique features such as the Spectrum Scope, Dual Watch and Twin PBT.