The Orion II has the highest close-in dynamic range at 1 kHz spacing
I have ever tested. At 50 kHz and 20 kHz, the dynamic range is
synthesizer noise limited at 95 dB. At 5 kHz the synthesizer loop is
quieter, and it measures 97 dB on 3rd order products. At 2 kHz it was
95 dB with the 600 Hz roofing filter and at 1 kHz it was 95 dB with
the 300 Hz roofing filter, both on IMD, not phase noise. All tests
were on 20 meters. There are things I don't like about the Orion II,
as with the Orion I, but that is true of any radio. There is no
perfect transceiver. If a near by station is bothering you, and you
are using an Orion II, it is likely the other guys fault: key clicks,
transmitted phase noise, SSB splatter, etc. At this point we are at
the limit due to IMD produced in the roofing filters, at least for
commercial, affordable products. In general, there is room for
improvement in the overall product, but not in dynamic range. The
close-in dynamic range is 10 dB better than most people need most of
the time. Full test data to be posted soon at www.nc0b.com.
http://www.eham.net/reviews/detail/5564
73, Bill W4ZV
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