> Bob, indeed the IC-7800's close-in phase noise is so bad that > measurements > of IMD and BDR are "noise limited". As is detailed in the August QST article > about Product Testing, ARRL chooses to measure the composite result including > phase noise issues (see 3rd paragraph under both BDR and IMD sections on page > 34 of August 2004 QST). G3SJX simply lists "noise limited" but ARRL's Expanded > Test Reports shows the composite result. Indeed the K2 beats the IC-7800 for > BDR but is equal for IMD at 1 kHz spacings. As has been discussed here > previously, the K2's close-in performance also degrades quite a > bit for signal spacings under 5 kHz. I'm not sure whether this is > due to filter blow-by or phase noise. Here are the comparative > measurements from ARRL's ETR's for the K2, IC-7800 and Orion at > 5 and 1 kHz spacings respectively: > > Rig IMD BDR (at 5/1 kHz spacings) > K2 91/67 134/116 > IC-7800 89/67 115/96 > Orion 92/84 130/118 > Bill; I have extensive measurements of the K2 phase noise on all bands. On 20 meters at a 20 kHz spacing, both the oscillator phase noise and the mixer IP3 contribute to the overall dynamic range. At less than 10 kHz, the phase noise is dominate and limits the DR3. I know that filter blow-by is not an issue at 5 kHz with the CW filter. Greater than 20 kHz, the K2 DR3 is primarily limited by the mixer IP3 and the DR3 gets up to about 100 dB. -John KI6WX
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