Raj
As requested. I have included a peak table to help in identifying the spurs.
970.jpg conditions: Yellow trace: 1 KHz audio drive = 15 mVRMS, RV1 set to 2 watts out, R27 attenuator set to -1 dB. Purple trace is the same but with R27 attenuator at -11 dB.
971.jpg conditions: Yellow trace: 1 KHz audio drive = 100 mVRMS, RV1 set to 2 watts out, R27 attenuator set to -1 dB. Purple trace is the same but with R27 attenuator at -11 dB.
I included 971 because I noted your tests were made with 100 mV audio input and my tests have shown that level is much too high. As you can see, the spurs are far worse at that input level due to very high IMD. Unless, of course, your 100 mV was Pk-Pk and not RMS.
Clearly, in both cases, we have spurs that are products of the 45 MHz mixing and those can be indentified by differing levels at the different attenuator settings. The ones that most concern me at this point are those that do now change in level when the R27 attenuation is increased.
WA8TOD
