[VHFcontesting] FT-817/897/847 overlaod
wa3tts at verizon.net
Tue Dec 15 13:44:09 PST 2009
Hi Everyone: Try good filters in the FT817/897/847. It costs $125 or more a filter, but the performance change is dramatic. I put the Collins 300Hz filter (Inrad #712) in my '847 and one in an 817. The improvement was so dramatic I went out and got the Collins 2.0KHz SSB filters (Inrad #720) a few weeks later for the 817 and for tx in the FT-847. There was room in my 847 for the Inrad 1.8KHz crystal filter, for receive, which has even better performance at the -60 to -80 range on their charts. You will also notice a 2db improvement on transmit with a narrow SSB filter versus a stock ceramic resonator. I have a second FT-817 I use the stock ceramic resonator for SSB and a 500 Hz filter for CW. I use that radio as an i.f. radio for the microwave bands, as the wider filter helps when tuning/searching for weak signals and I still can go narrow to improve the S/N when needed. I would put the 300Hz cwfilter in that radio as well, but eventually you drain the budget. My FT-847 is actually usable now for a 160m cw contest effort with the filter upgrades. One other comment. I notice the dynamic range goes to pot on the FT-847 with the noise blanker on. I'm not sure how true that is on the 817 or 897, but try turning the NB off the next time your front end gets hammered on. Don't forget that RF gain control knob does work. Find a weak VHF or UHF beacon and see how far you can turn down the RF gain without giving up that much hearing performance.
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